Name: comprehensive characterization of extended defects in semiconductor materials by a scanning electron microscope
Uploaded: 2016-05-28T14:00:00.000+00:00
Duration: 11 min 14 s
Description: Watch this Scientific Journal Video about Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope at JoVE.com

Support of this work by the German Research Foundation (DFG) within the framework of the Research Training Group 1621 is gratefully acknowledged by Paul Chekhonin. All authors are grateful to Dietmar Temmler (Fraunhofer FEP Dresden) for providing the electron beam processed Si samples showing liquid phase re-crystallisation. Special thanks go to Stefan Saager and Jakob Holfeld for the preparation of the figures for the SEM equipment and the EBSD set-up. We thank Michael Stavola for detailed discussions and help with this work.

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The authors have nothing to disclose.

SEMは、半導体材料に拡張された欠陥の位置を特定するだけでなく、ccEBSD、CLとEBIC調査の適用により、その構造の光学的および電気的特性を特徴づけるために可能性を提供しています。一般的には、同じサンプル上で同時にすべての3つの方法を実行することは不可能です。合理的な順序で実行するときしかし、異なる補完的な調査方法によって得られた結果の組み合わせは、拡張欠陥による影響の物理的性質のより深い理解につながります。 拡張された欠陥の光学特性に関する情報を与えるCL測定では、プロトコルにおける重要なステップが原因財を保証するインジウム箔（の加熱中、試料中の欠陥の望ましくないアニーリングに対する試料位置決め手順（ステップ1.6）であり、試料ホルダーと試料の熱と電気的接触）。提案された手順の代わりRTで導電性銀ペーストにより試料ホルダー上にサンプルをマウントすることです。しかしながら、経験から、ペースト中の有機溶媒は、SEMの走査中、試料表面上の炭素汚染を引き起こすことが知られています。汚染は、EBSD回折パターンならびにCL画像の品質を劣化させます。さらに、ステップ4.21は、シリコンの発光強度の急激な上昇は、サンプルの冷却ダウン中に発生する可能性がある特別な注意が必要です。これは、光電子増倍管の性能に悪影響を与えることができます。予備ミラーアライメントをRTで試験試料で行ったので、逆に、実際のサンプルのために予期しない低い発光強度の場合、1つの集光ミラー（プロトコル番号4.23）の調整を改善することを試みるべきです波長のわずかに異なる範囲。 メソッドのインストゥルメンタルの制限については、1は、その非常に低いtemperatで考慮に入れる必要がありますサンプルとステージが調査中のサンプルの面積を制限x、y方向にのみ±5mmだけ移動することができURES。この制限は、ヘリウム移送管の脆性破壊の危険性に起因します。 1.1と1.2で与えられた低温実験用の試料寸法はまた、実験条件によって制限されています。そのように試料の表面積は、ヒートシンクの最適な熱接触を確実にするために試料ホルダの大きさに調整されるべきです。シリコンサンプルの低推奨厚さは低温実験のために、試料中の温度勾配を制限します。 200μmの試料の厚さについては、表面領域中の一次電子の相互作用体積の中心での温度は、試料ホルダの表面で測定された温度と比較して5未満のKによって増加することが見出されました。高い走査速度とステップ4.5および4.17でのみクールダウン手続きのために提案低倍率、その目を確保関心のE領域は清潔に保たれています。これは、SEMチャンバ内の残留ガスのための凝縮トラップとして作用するサンプル領域の残りの部分の温度より常にわずかに温度を維持し、走査電子ビームによる熱伝達です。一般的に、CL分光法のためのステップ4.24に記載されているすべてのパラメータは、機器のリストに従って設定した実験により、バルクシリコン中のいわゆるD線発光の測定のために最適化されています。発光の研究は他の半導体材料上で実行される場合、パラメータが適合されなければなりません。 観察された発光のエネルギー範囲の独立した、全組換えボリュームに放射再結合プロセスからの光は、このようにミラーによって収集しているので集光ミラーからのCL測定結果のさらなる制限は、対応するグレー値を決定します割り当てであるCLの画像画素試料表面上の電子ビームの位置にED。 （励起体積に匹敵する）組換えボリュームの直径も低倍率の画素サイズよりも大きいので、この効果は、発光シグナルの空間的な汚れを引き起こし、そして、したがって、空間分解能を制限します。それにもかかわらず、CLの調査は、媒体のスペクトル分解能でモノまたはパンクロマチック発光の局所分布のイメージングを可能にし、高いスペクトル分解能を与えるためにフォトルミネッセンスの調査と組み合わせることができます。最近では、測定値をCLに代替実験方法として、転位の顕微鏡と分光マッピングに関連するフォトルミネッセンスは、田島と同僚26のグループによって提案されました。フォトルミネッセンスマッピングの空間分解能は、CLの画像に比べて明らかに低いですが、フォトルミネセンスの調査は、さらに深いレベルの発光バンドカレの偏光を可能にします転位にされた関連のツイストとチルト構造27,28とLAGBsに決定されます。 拡張欠陥の電気的特性への洞察を与えるEBIC調査の場合には、比較的空間分解能を有する半導体材料で局所的に変化する電荷収集効率のイメージングのための代替の方法が存在しません。しかしながら、EBIC測定のために、重要なステップは、プロトコルに含まれています。だから、ステップ5.13で、温度を下げるとEBIC像の変化は、拡張欠陥の温度依存特性から生じると予想されます。しかし、コンタクトの品質を室温以下の温度で変化し、従ってEBIC画像に影響を与えることができます。温度が原因インシリコからコンタクト層を分離する異なる熱膨張係数を、n型シリコンの場合にはp型の場合とAuとAlとの適切な層で作られたショットキー接触に影響しますN基板。また、ガリウム - インジウム共晶によって作られたオーミック接触が160 K.通常より低い温度で安定していない、接触の質の低下がにつながる強く大きな領域のためEBIC信号を減少させました。この場合、連絡先は更新されなければなりません。 RTでEBIC調査のために、EBSD測定のための接触は、適切なキャリアボードにサンプルを結合することによって作製することができることも考えられます。 EBIC測定の他の楽器の限界は、試料表面上のコンタクトチップホルダの突出によって引き起こされます。コンタクトチップホルダーとSEMのポールピース間の衝突を防ぐために、WDは、少なくとも15ミリメートルでなければなりません。 拡張欠陥の長距離歪み場を推定するために使用することができるccEBSD調査のための実験手順では、以下のステップが重要です。実験の最も困難な部分は、試料調製、特に最後の研磨手順（pは付加的な表面欠陥の発生を回避するために慎重に行われなければならないrotocol番号3.1）。何菊地パターンを得ることができない場合は、多くの場合、試料表面の品質が十分ではありません。しかし、塑性変形後の表面上のすべり線を有するシリコン単結晶から、良好な回折パターンはccEBSD評価手順に非常に適してあった得ることができました。これらの試料の表面粗さは、最大500ナノメートルの範囲内の高さの変化を生じる原子間力顕微鏡により分析しました。そのため、非常に高い内部歪み又はアモルファス表面層がぼやけ回折パターンではなく、試料表面の不完全な滑らかさの原因であると思われます。さらなる問題は、バックグラウンドと比較してコヒーレントに散乱された電子からの低い信号である可能性があります。次いで、一定の加速電圧でプローブ電流の増加および/またはバックグラウンドシグナル（プロトコルのステップ番号6.12）Aのより正確な決意参考に再度。長期的なccEBSD測定中の試料の動きを最小限に抑えるために、それは機械的にサンプルを固定することをお勧めします（プロトコル番号3.2）。 入射電子ビームの試料表面の傾きが段の傾斜によって実現される場合ccEBSD調査のためのインストゥルメンタルの制限が生じ得ます。ポールピースとチャンバ壁との衝突の危険性に起因するサンプルの移動のための強力な制限は、次にあります。さらに、強くによるサンプルのエラーのために、まず、垂直走査が内部歪みのために多額のエラーを持っているので、（したがって、SEMの画面上に水平に表示されます）傾斜軸に平行なラインだけスキャンを使用することをお勧めしますチルト。第二に、EBSDの間に、横方向の解像度はそれに垂直より傾斜軸に沿って高い（70°傾斜のための約3倍）です。 ccEBSD調査からSiのために計算されたひずみテンソルコンポーネントの値の下限はありますランダム誤差である2×10 -4。さらにはccEBSD技術は大きな格子回転の存在下では適用できないことを強調しなければならない（&gt; 4°）の基準点を参照し、または異なる粒子のEBSDパターンが重なって粒界に非常に近いです。ひずみ決意の空間分解能に関するccEBSD調査の物理的限界は、試料傾斜軸に沿って約50nmであることが判明した電子線回折の範囲によるものです。内部歪みの決意のX線回折実験と比較して、これが原因であってもX線μ回折の場合にX線のかなり大きな相互作用体積の明らかな利点です。半導体材料は、polarscopeによって等方性の屈折率の摂動の研究はまた、内部応力の決意に適用することができるが、この方法の空間分解能はより低いですいくつかの百nmの29。結晶中の空間分解3次元ひずみ状態の決意ための別の方法は、より高次ラウエ帯（HOLZ）線の分割に基づいています。この方法は、電子干渉計30の電子線バイプリズムを用いた透過型電子顕微鏡（TEM）で実行されなければなりません。しかし、SEMでccEBSD調査とは対照的に、TEM調査は、リラクゼーション効果による内部歪みを変更するサンプルからの箔の準備が必要です。 将来の研究では、ccEBSD測定も低い温度で行われます。これは、同じ拡張欠陥でなく、同​​じ温度でだけでなく、調査を、構造上の光学的および電気的特性を可能にします。

これは、欠陥が半導体材料1-3の電子構造に影響を与える拡張何十年も知られています。電子機器やセンサや太陽電池材料などの他のアプリケーションのパフォーマンスに拡張欠陥の影響が広範囲に及ぶ実験的および理論的な調査中です。それにもかかわらず、拡張欠陥の存在下での半導体の電子状態の計算には一般的に受け入れられている理論はありません。これは、理想的な結晶格子から逸脱した場合の電子構造計算の複雑さにも拡張された欠陥の種類や設定に関する大規模な多様性だけでなく、それらの間でと0次元の固有で可能な組み合わせにとあります外因性の欠陥。 拡張欠陥の主なタイプは、転位（1次元欠陥）と結晶粒界（2次元欠陥）です。以下では、我々は共同しました走査型電子顕微鏡（SEM）で行うことができる実験条件における拡張欠陥のこれらのタイプの両方にncentrate。ここで紹介する実験方法は、したがって、拡張欠陥を含む半導体材料における電子状態の間接的な知識を拡張欠陥の構造光学的および電気的特性についての情報を提供します。欠陥に関連する電子状態の制御は、半導体の用途および半導体デバイスの動作のための中心的な課題です。 拡張欠陥の構造の調査のために、電子後方散乱回折（EBSD）法を適用することができます。通常、EBSD測定を各点で静止電子ビームをポイントマッピングすることによって行われます。 EBSDは、次いで、単結晶材料の場合には多結晶材料における結晶粒の試料の結晶格子の結晶方位についての情報を与えます。フォーR菊池バンドによって形成された実験的に決定された回折パターンを有し、その目的は、材料の結晶の空間群の決定、シミュレートパターンと比較することによって分析されます。方位データの評価のためのソフトウェアは、隣接するマッピング点の結晶座標系との間の方位差角を計算することができる場合は、それらの間の粒界のタイプを決定することができます。方位差角が15°よりも小さい場合、低角粒界（LAGB）が存在します。それ以外の場合は、高角度粒界（HAGB）です。 HAGBの種類は、Σ-1は一致格子の上に横たわって格子点の割合であり、そのΣ値によって特徴付けられます。対称性の高い双晶境界4だから、Σ= 3スタンド。試料表面の二つの面にEBSDマッピングは、マッピングの位置の正確な知識を有する粒界面Wの種類を測定することができる場合i番目のミラーはHKLもランドル5によって提案された方法によって評価することができる指標。 最近、電子回折パターンの評価のための新しい手順は、ウィルキンソンらによって得られた。6完全な局所ひずみテンソルのすべての構成要素、 すなわち、の計算を可能にする3つの垂直ひずみ三剪断歪の絶対値コンポーネント。この計算は、同じ結晶方位を有する歪みのない結晶領域に沿った基準パターンに対して、対応する回折パターンのマ​​ッピングの各測定点について行われます。この評価手順は、名前ccEBSDを与える相互相関技術を用いてEBSDパターンの特徴の小さなシフトの決意に基づいています。選択された基準点に対する、歪成分と格子回転が10 -4と0.006＆＃の精度で測定することができます176 ;,それぞれ7。結晶粒界を横切るラインスキャン中、または転位の取り決めに沿ってccEBSD測定を適用すると、1は、ローカル金額並びにこれらの拡張欠陥の歪場の範囲を決定することができます。 転位や結晶粒界の光学特性は、分光及びイメージングカソードルミネッセンス（CL）法により調べることができます。発光シグナルは、SEMの一次電子ビームによって半導体材料内に生成される電子 - 正孔対の放射再結合によって引き起こされます。発光の強度は、放射再結合時間に合計少数キャリアライフタイムの比率である発光再結合効率に比例します。この比は、欠陥によって局所的に影響を受けた場合、発光分布のコントラストがCL像で観察することができます。通常、拡張された欠陥は、したがって、Lは、非発光再結合中心として作用しバンドバンドの再結合からuminescenceは邪魔されず、半導体に比べて拡張欠陥の近傍に低下します。しかし、転位にならびに粒界上にSi、Geおよびいくつかの化合物半導体材料の場合には、特徴的な発光バンドは、（直接または非直接）バンド間再結合のより低い光子エネルギーを示す観察されますバルク材料8〜10インチ例として、結合したシリコンウェーハのと関口や同僚11-13により多結晶シリコンの豊富なCL調査は、転位やLAGBsは、バンドギャップが浅いと深いレベルの発生に関与していることを明らかにしました。対応する放射遷移はCLスペクトルのD線として示されています。それにもかかわらず、酸素析出と遷移金属不純物によって転位の転位汚染の配置に伴う歪み場の役割はinterpretatため依然として議論がありますD線発光のイオン。異なる拡張欠陥の発光線のエネルギー位置の割り当てが正常に行うことができる場合には、その後、発光スペクトルにおけるこの特定の行の発生は、この欠陥の存在のための信号とすることができます。発光強度を増加させるために、すなわち 、非放射いずれかに関連して放射再結合は、CLの調査は、間接バンド構造を有する半導体材料の低温（冷凍CL）で実行されなければなりません。 ここで考慮拡張欠陥の電気的特性は、SEMの電流（EBIC）が誘導され、電子ビームを撮像することによって特徴付けられます。一次電子ビームによって発生した電子 - 正孔対が内蔵電界によって分離されている場合、この電流を観察することができます。このフィールドは、拡張欠陥自体の電位によって、または試料表面にショットキー電極によって生成することができます。 EBIC像電気的に活性な欠陥で様々な再結合の挙動に起因する電荷収集効率の局所的な変動の結果を対比。彼らは欠陥のない領域よりEBIC像で暗く表示されるように拡張欠陥は、通常は増加し、キャリアの再結合を示しています。欠陥14の物理ベースモデルの枠組みの中で、コントラストプロファイルと呼ばれるEBIC信号の空間依存性の定量的評価は、少数キャリア拡散長と寿命の決意だけでなく、表面再結合速度を可能にします。これらのパラメータは、温度に依存するので、EBIC調査はまた雑音比に強調信号を得るために、低い温度（低温EBIC）で実施されるべきです。また、温度依存EBIC測定はキトラーと同僚15,16によって提案されたモデルに従って、転位で深いレベルの不純物の濃度の決意を有効にします。 17によって著しく影響され得ることに留意すべきです。しかし、実験方法、ccEBSD、CLとEBICの組み合わせは、拡張欠陥を視覚化するとSEMでの基本的な性質を定量化する機会を提供しています。将来のアプリケーションだけでなく、障害の解析だけでなく、制御および欠陥エンジニアリングが意図される欠陥を、この強力なツールは、半導体デバイスの性能の向上に重要な役割を果たします。

<table><tbody><tr><td>Cryogenic liquids:&amp;nbsp;&amp;nbsp;&amp;nbsp;</td><td>Linde http://www.linde-gas.de, Air Liquide http://www.airliquide.de/</td><td></td><td></td></tr><tr><td>Liquid helium ( LHe )</td><td></td><td></td><td>for cooling of the cryostat</td></tr><tr><td>Liquid nitrogen ( LN2 )</td><td></td><td></td><td>for cooling of the PMT R5509-73</td></tr><tr><td>Indium wire</td><td>chemPUR http://chempur.de/&amp;nbsp;</td><td>900898</td><td>CL sample preparation: for good electrical and thermal coupling between cryostat and sample</td></tr><tr><td>Mica</td><td>plano GmbH http://www.plano-em.de/&amp;nbsp;</td><td>V3</td><td>isolation of EBIC sample holder and good thermal coupling to the cryostat</td></tr><tr><td>Aluminium wire, gold wire</td><td>chemPUR http://chempur.de/&amp;nbsp;</td><td>009013, 900891</td><td>purity 99.99%, material for formation of Schottky contact for EBIC measurements</td></tr><tr><td>Indium-Gallium eutectic solution</td><td>Alfa Aesar&amp;nbsp;</td><td>12478</td><td>to form ohmic contact on the backside of the sample for EBIC measurements</td></tr><tr><td>Liquid chemicalsVLSI Selectipur&lt;br/&gt; &amp;nbsp;(de-ionized water, acetone, ethanol)</td><td>VWR</td><td>52182674,&lt;br/&gt; 51152090</td><td>for sample preparation: cleaning and surface treatment</td></tr><tr><td>Hydrofluoric acid</td><td>VWR</td><td>1,003,382,500</td><td>necessary to remove surface oxide layer on Silicon samples immediately before investigation; follow safety precautions!&amp;nbsp;</td></tr><tr><td>MicroCloth</td><td>Buehler http://www.buehler.com/&amp;nbsp;</td><td>40-7222</td><td>polishing cloth</td></tr><tr><td>MasterMet 1 (0.02 &amp;micro;m)</td><td>Buehler http://www.buehler.com/&amp;nbsp;</td><td>40-6380-006</td><td>SiO&lt;sub&gt;2&lt;/sub&gt; polishing suspension</td></tr><tr><td>Scanning electron microscope (SEM)</td><td>Carl Zeiss AG http://www.zeiss.de/microscopy/&amp;nbsp;</td><td>Ultra 55</td><td>field emission gun</td></tr><tr><td>SEM-CL system</td><td>EMSystems</td><td></td><td>customized, following equipment belongs to CL system:</td></tr><tr><td>&amp;nbsp;SEM stage for cryostat</td><td>Kammrath &amp;amp; Weiss http://www.kammrath-weiss.com&amp;nbsp;</td><td></td><td></td></tr><tr><td>KONTI cryostat</td><td>Cryovac http://www.cryovac.de/</td><td>3-06-4609C-7674</td><td>cooling of sample</td></tr><tr><td>Liquid He transfer line for KONTI cryostat</td><td>Cryovac http://www.cryovac.de/</td><td>3-01-3506C-SO</td><td></td></tr><tr><td>Cryogenic Temperature Controller</td><td>Cryovac http://www.cryovac.de/</td><td>TIC-304 MA</td><td>controlling the flow rate of cryogenic</td></tr><tr><td>Photomultiplier Tube (PMT)&amp;nbsp;</td><td>Hamamatsu http://www.hamamatsu.com</td><td>R5509-73</td><td>for NIR spectral range&amp;nbsp;</td></tr><tr><td>PMT housing and cooler</td><td>Hamamatsu http://www.hamamatsu.com</td><td>C9940-2</td><td></td></tr><tr><td>HV power supply&amp;nbsp;</td><td>Heinzinger electronic GmbH http://www.heinzinger.de/</td><td>LNC 3000-10 neg</td><td>for operating of the PMT</td></tr><tr><td>Monochromator&amp;nbsp;</td><td>Sol Instruments Ltd. http://www.solinstruments.com</td><td>MS2004i</td><td></td></tr><tr><td>PMT&amp;nbsp;</td><td>Hamamatsu http://www.hamamatsu.com</td><td>R3896</td><td>for visible spectral range</td></tr><tr><td>CCD digital camera&amp;nbsp;</td><td>Proscan GmbH, Proscan Special Instruments Ltd. http://www.proscan.de</td><td>HS 101 H</td><td>for visible spectral range</td></tr><tr><td>Control program</td><td>Proscan GmbH, Proscan Special Instruments Ltd. http://www.proscan.de</td><td>PSI line</td><td>for controlling spectral CL measurements with CCD or PMT detectors</td></tr><tr><td>Laptop</td><td>Dell</td><td>Latitude 110L</td><td>hardware for running the control program</td></tr><tr><td>&amp;nbsp;LHe dewar</td><td>cryotherm http://www.cryotherm.de/</td><td>Stratos 100 SL</td><td>container for cryogenic</td></tr><tr><td>LN2 dewar</td><td></td><td></td><td>container for cryogenic</td></tr><tr><td>Protective glasses</td><td>pulsafe</td><td></td><td>protective equipment</td></tr><tr><td>Protective gloves</td><td>tempex</td><td>Protect line&amp;nbsp; Mod. 4081052</td><td>protective equipment</td></tr><tr><td>Heating tape</td><td>Thermocax Isopad GmbH http://www.isopad-solutions.com</td><td>IT-TeMS 6</td><td>to prevent or reduce icing of the flexible hoses during cooling</td></tr><tr><td>Diaphragm pump&amp;nbsp;</td><td>Vacuubrand GmbH &amp;amp; Co KG http://www.vacuubrand.com</td><td>ME4</td><td>to provide the flow rate of the cryogenic</td></tr><tr><td>Vacuum accessoires: flexible hoses, seals, locking rings</td><td></td><td></td><td>connectors for cryogenic CL or EBIC set-up</td></tr><tr><td>Specimen current EBIC amplifier</td><td>KE developments / Deben http://deben.co.uk/</td><td>Type 31</td><td>Measuring the EBIC current</td></tr><tr><td>High vacuum chamber with metal evaporation</td><td>customized</td><td></td><td>formation of Schottky contact for EBIC measurements</td></tr><tr><td>Heating plate</td><td>Retsch GmbH http://www.retsch.de</td><td>SG1</td><td>CL sample preparation</td></tr><tr><td>EBSD detector Nordlys</td><td>HKL</td><td></td><td>no more available; can be replaced by the Oxford EBSD detectors NordlysMax3 or NordlysNano</td></tr><tr><td>EBSD acquisition and evaluation software Channel 5</td><td>HKL</td><td></td><td>no more available; can be replaced by the Oxford EBSD Software AZtecHKL</td></tr><tr><td>ccEBSD program ccEBSD_v1.07.exe</td><td>in house written program</td><td></td><td>for use please contact authors</td></tr><tr><td>EBSD interface with remote control system</td><td>Carl Zeiss AG http://www.zeiss.de/microscopy/&amp;nbsp;</td><td></td><td>necessary for the electron beam control and parameter transfer between EBSD system and SEM&amp;nbsp;&amp;nbsp;</td></tr><tr><td>Vibromet2</td><td>Buehler, http://www.buehler.com/&amp;nbsp;</td><td>671635160</td><td>vibratory polisher</td></tr></tbody></table>

comprehensive characterization of extended defects in semiconductor materials by a scanning electron microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

Watch this Scientific Journal Video about Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope at JoVE.com

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

走査型電子顕微鏡による半導体材料における拡張欠陥の総合的な特性評価

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

comprehensive-characterization-extended-defects-semiconductor

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Basics of Semiconductors

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13.6K ビュー.  Technische Universität Dresden. The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons. 

ビデオ: Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Scanning-probe Single-electron Capacitance Spectroscopy

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the electronic quantum structure of small systems - including individual atomic dopants in semiconductors. Here we present a capacitance-based method, known as Subsurface Charge Accumulation (SCA) imaging, which is capable of resolving single-electron charging while achieving sufficient spatial resolution to image individual atomic dopants. The use of a capacitance technique enables observation of subsurface features, such as dopants buried many nanometers beneath the surface of a semiconductor material1,2,3. In principle, this technique can be applied to any system to resolve electron motion below an insulating surface.
As in other electric-field-sensitive scanned-probe techniques4, the lateral spatial resolution of the measurement depends in part on the radius of curvature of the probe tip. Using tips with a small radius of curvature can enable spatial resolution of a few tens of nanometers. This fine spatial resolution allows investigations of small numbers (down to one) of subsurface dopants1,2. The charge resolution depends greatly on the sensitivity of the charge detection circuitry; using high electron mobility transistors (HEMT) in such circuits at cryogenic temperatures enables a sensitivity of approximately 0.01 electrons/Hz&frac12; at 0.3 K 5.

Scanning-probe single-electron capacitance spectroscopy facilitates the study of single-electron motion in localized subsurface regions. A sensitive charge-detection circuit is incorporated into a cryogenic scanning probe microscope to investigate small systems of dopant atoms beneath the surface of semiconductor samples.

走査プローブ単電子容量分光

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the ...

工学

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging (ECCI) in a scanning electron microscope (SEM). ECCI allows for imaging of defects and crystallographic features under specific diffraction conditions, similar to that possible via plan-view transmission electron microscopy (PV-TEM). A particular advantage of the ECCI technique is that it requires little to no sample preparation, and indeed can use large area, as-produced samples, making it a considerably higher throughput characterization method than TEM. Similar to TEM, different diffraction conditions can be obtained with ECCI by tilting and rotating the sample in the SEM. This capability enables the selective imaging of specific defects, such as misfit dislocations at the GaP/Si interface, with high contrast levels, which are determined by the standard invisibility criteria. An example application of this technique is described wherein ECCI imaging is used to determine the critical thickness for dislocation nucleation for GaP-on-Si by imaging a range of samples with various GaP epilayer thicknesses. Examples of ECCI micrographs of additional defect types, including threading dislocations and a stacking fault, are provided as demonstration of its broad, TEM-like applicability. Ultimately, the combination of TEM-like capabilities &#8211; high spatial resolution and richness of microstructural data &#8211; with the convenience and speed of SEM, position ECCI as a powerful tool for the rapid characterization of crystalline materials.

The use of electron channeling contrast imaging in a scanning electron microscope to characterize defects in III-V/Si heteroexpitaxial thin films is described. This method yields similar results to plan-view transmission electron microscopy, but in significantly less time due to lack of required sample preparation.

迅速なIII-Vヘテロ特徴付けのための電子チャネリングコントラストイメージング

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging ...

In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography (CT) and Light Microscopy (LM) Correlated with Scanning Electron Microscopy (SEM)

In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of micro-characterization, plays an important role. Commonly, different techniques like X-ray computed tomography (CT), light microscopy (LM) and scanning electron microscopy (SEM) are used separately. Similarly, the results have to be treated for each technique independently. Here a comprehensive study is shown which demonstrates the potentials leveraged by linking CT, LM and SEM. In depth characterization is performed on a white emitting LED, which can be operated throughout all characterization steps. Major advantages are: planned preparation of defined cross sections, correlation of optical properties to structural and compositional information, as well as reliable identification of different functional regions. This results from the breadth of information available from identical regions of interest (ROIs): polarization contrast, bright and dark-field LM images, as well as optical images of the LED cross section in operation. This is supplemented by SEM imaging techniques and micro-analysis using energy dispersive X-ray spectroscopy.

In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography CT and Light Microscopy LM Correlated with Scanning Electron Microscopy SEM

A workflow for comprehensive micro-characterization of active optical devices is outlined. It contains structural as well as functional investigations by means of CT, LM and SEM. The method is demonstrated for a white LED which can be still be operated during characterization.

走査型電子顕微鏡（SEM）と相関X線コンピュータ断層撮影（CT）および光学顕微鏡（LM）の組合せによるLEDの深さ分析で

In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of ...

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The characteristics of the C84-embedded Si surface, such as atomic resolution topography, local electronic density of states, band gap energy, field emission properties, nanomechanical stiffness, and surface magnetism, were examined using a variety of surface analysis techniques under ultra, high vacuum (UHV) conditions as well as in an atmospheric system. Experimental results demonstrate the high uniformity of the C84-embedded Si surface fabricated using a controlled self-assembly nanotechnology mechanism, represents an important development in the application of field emission display (FED), optoelectronic device fabrication, MEMS cutting tools, and in efforts to find a suitable replacement for carbide semiconductors. Molecular dynamics (MD) method with semi-empirical potential can be used to study the nanoindentation of C84-embedded Si substrate. A detailed description for performing MD simulation is presented here. Details for a comprehensive study on mechanical analysis of MD simulation such as indentation force, Young&#39;s modulus, surface stiffness, atomic stress, and atomic strain are included. The atomic stress and von-Mises strain distributions of the indentation model can be calculated to monitor deformation mechanism with time evaluation in atomistic level.

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports the nanomaterial fabrication of a fullerene Si substrate inspected and verified by nanomeasurements and molecular dynamic simulation.

Cプロービング<sub&gt; 84</sub&gt;走査型プローブ顕微鏡および分子動力学を用いたSi基板を-embedded

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The ...

Characterization of Ultra-fine Grained and Nanocrystalline Materials Using Transmission Kikuchi Diffraction

One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and nanocrystalline materials. The traditional techniques associated with scanning electron microscopy (SEM), such as electron backscatter diffraction (EBSD), do not possess the required spatial resolution due to the large interaction volume between the electrons from the beam and the atoms of the material. Transmission electron microscopy (TEM) has the required spatial resolution. However, due to a lack of automation in the analysis system, the rate of data acquisition is slow which limits the area of the specimen that can be characterized. This paper presents a new characterization technique, Transmission Kikuchi Diffraction (TKD), which enables the analysis of the microstructure of UFG and nanocrystalline materials using an SEM equipped with a standard EBSD system. The spatial resolution of this technique can reach 2 nm. This technique can be applied to a large range of materials that would be difficult to analyze using traditional EBSD. After presenting the experimental set up and describing the different steps necessary to realize a TKD analysis, examples of its use on metal alloys and minerals are shown to illustrate the resolution of the technique and its flexibility in term of material to be characterized.

This paper provides a detailed method to characterize the microstructure of ultra-fine grained and nanocrystalline materials using a scanning electron microscope equipped with a standard electron backscatter diffraction system. Metal alloys and minerals presenting refined microstructures are analyzed using this technique, showing the diversity of its possible applications.

トランスミッション菊池回折を用いて超微細粒とナノ結晶材料のキャラクタリゼーション

One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

のための新しい方法<em&gt;現場で</em&gt;ナノスケール試料の電気機械的特性

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new techniques capable of characterizing their dynamics. Investigating single dopants requires sub-nanometer spatial resolution, which motivates the use of scanning tunneling microscopy (STM). However, conventional STM is limited to millisecond temporal resolution. Several methods have been developed to overcome this shortcoming, including all-electronic time-resolved STM, which is used in this study to examine dopant dynamics in silicon with nanosecond resolution. The methods presented here are widely accessible and allow for local measurement of a wide variety of dynamics at the atomic scale. A novel time-resolved scanning tunneling spectroscopy technique is presented and used to efficiently search for dynamics.

We demonstrate an all-electronic method to observe nanosecond-resolved charge dynamics of dopant atoms in silicon with a scanning tunneling microscope.

すべて電子ナノ秒分解走査型トンネル顕微鏡: 単一ドーパントの電荷ダイナミクスの調査を促進します。

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new ...

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

A novel elemental and chemical analysis scheme based on electron-channeling phenomena in crystalline materials is introduced, where the incident high-energy electron beam is rocked with the submicrometric pivot point fixed on a specimen. This method enables us to quantitatively derive the site occupancies and site-dependent chemical information of impurities or intentionally doped functional elements in a specimen, using energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy attached to a scanning transmission electron microscope, which is of significant interest to current materials science, particularly related to nanotechnologies. This scheme is applicable to any combination of elements even when the conventional Rietveld analysis by X-ray or neutron diffraction occasionally fails to provide the desired results because of limited sample sizes and close scattering factors of neighboring elements in the periodic table. In this methodological article, we demonstrate the basic experimental procedure and analysis method of the present beam-rocking microanalysis.

We provide a general outline of quantitative microanalysis methods for estimating the site occupancies of impurities and their chemical states by taking advantage of electron-channeling phenomena under incident electron beam-rocking conditions, which reliably extract information from minority species, light elements, oxygen vacancies, and other point/line/planar defects.

電子チャネリング強化マイクロ分析による結晶材料における機能的ドーパント/点欠陥の定量的原子部位解析

A novel elemental and chemical analysis scheme based on electron-channeling phenomena in crystalline materials is introduced, where the incident ...

化学

A Virtual Simulation Experiment of Mechanics: Material Deformation and Failure Based on Scanning Electron Microscopy

This work presents a set of comprehensive virtual experiments to detect material deformation and failure. The most commonly used pieces of equipment in mechanics and material disciplines, such as a metallographic cutting machine and a high-temperature universal creep testing machine, are integrated into a web-based system to provide different experimental services to users in an immersive and interactive learning environment. The protocol in this work is divided into five subsections, namely, the preparation of the materials, molding the specimen, specimen characterization, specimen loading, nanoindenter installation, and SEM in situ experiments, and this protocol aims to provide an opportunity for users regarding the recognition of different equipment and the corresponding operations, as well as the enhancement of laboratory awareness, etc., using a virtual simulation approach. To provide clear guidance for the experiment, the system highlights the equipment/specimen to be used in the next step and marks the pathway that leads to the equipment with a conspicuous arrow. To mimic the hands-on experiment as closely as possible, we designed and developed a three-dimensional laboratory room, equipment, operations, and experimental procedures. Moreover, the virtual system also considers interactive exercises and registration before using chemicals during the experiment. Incorrect operations are also allowed, resulting in a warning message informing the user. The system can provide interactive and visualized experiments to users at different levels.

This work presents a three-dimensional virtual simulation experiment for material deformation and failure that provides visualized experimental processes. Through a set of experiments, users can become familiar with the equipment and learn the operations in an immersive and interactive learning environment.

走査型電子顕微鏡による力学の仮想シミュレーション実験:材料の変形と破壊

This work presents a set of comprehensive virtual experiments to detect material deformation and failure. The most commonly used pieces of equipment in ...

<meta charset="utf8"></head><body>歯内療法における単一および複数回の使用後のNiTiファイルの表面欠陥

Scanning Electron Microscopic Evaluation of Surface Defects of Remover Retreatment File After Single and Multiple Uses

This study aimed to evaluate surface defects of Remover rotary Nickel-Titanium (NiTi) files after single and multiple uses in conventional endodontic retreatment procedures using scanning electron microscopy (SEM). Eighty acrylic blocks, simulating root canals with a 1.5 mm internal diameter, a 5 mm radius of curvature, and a 55&#176; curvature, were utilized. After chemomechanical preparation and obturation, 24 new Remover files (N30, 7%, L23) were randomly assigned to three groups: single use, triple use, and six uses. The files were operated at 600 rpm with a torque of 2.5 Ncm, cleaned, and sterilized after each use.
SEM analysis at magnifications of 100x, 250x, and 500x revealed surface defects, including tip deformation, microcracks, fracture, unwinding, surface pitting, and blade disruption. Deformation was observed in 75% of the files after a single use and in 100% of the files after three and six uses. Microcracks were absent after single use but appeared in 25% and 87.5% of files after three and six uses, respectively, showing a statistically significant increase (p &#60; 0.001). Surface pitting also significantly increased among groups (p = 0.004).
No fractures were observed in any group. The most common defects were tip deformation (91.7%) and surface pitting (70.8%). The findings suggest that repeated use of NiTi files significantly increases surface defects, elevating the risk of fatigue fractures. Thus, the results recommend limiting the reuse of Remover files to a maximum of 3x. Further research is needed to correlate defect types with anatomical factors and to assess file effectiveness in retreatment scenarios.

<meta charset="utf8"></head><body>リムーバー再処理ファイルの表面欠陥の走査型電子顕微鏡評価

Here, we present a protocol for evaluating the surface characteristics of endodontic retreatment files after repeated use in retreatment procedures, utilizing scanning electron microscopy to identify and analyze potential surface defects.

リムーバー再処理ファイルの表面欠陥の走査型電子顕微鏡評価

This study aimed to evaluate surface defects of Remover rotary Nickel-Titanium (NiTi) files after single and multiple uses in conventional endodontic ...

走査型電子顕微鏡による半導体材料における拡張欠陥の総合的な特性評価

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