Name: formation of thick dense yttrium iron garnet films using aerosol deposition
Uploaded: 2015-05-15T15:00:00
Description: Watch this Scientific Journal Video about Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition at JoVE.com

SDJ gratefully acknowledges the support of the American Association for Engineering Education/NRL Postdoctoral Fellowship Program, discussions with Konrad Bussmann (NRL) and Mingzhong Wu (Colorado State University) on the magnetic properties of materials, and Ron Holm (NRL) for his part in the design and implementation of the NRL AD system.

1. Powder Preparation
<ol>
	<li>Sieve as-received yttrium iron garnet (YIG) powder to obtain 100&#8211;150 g of agglomerates sized less than 53 &#181;m.</li>
	<li>Place the sieved powder into a furnace to dry for at least 24 hr at a temperature greater than 300 &#176;C.</li>
</ol>
2. Substrate Preparation
<ol>
	<li>Clean a substrate of desired size, e.g., 3 mm x 3 mm using acetone then isopropanol. Dry using nitrogen gas.</li>
</ol>
3. Performing Aerosol Depositi...

<ol>
	<li>Akedo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Room+Temperature+Impact+Consolidation+(RTIC)+of+Fine+Ceramic+Powder+by+Aerosol+Deposition+Method+and+Applications+to+Microdevices.">Room Temperature Impact Consolidation (RTIC) of Fine Ceramic Powder by Aerosol Deposition Method and Applications to Microdevices.</a> J. of Therm. Spray tech. 17, 181 (2008).</li><li>Hahn, B. D., Park, D. -. S., Choi, J. -. J., Ryu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoconductive+hydroxyapatite+coated+PEEK+for+spinal+fusion+surgery.">Osteoconductive hydroxyapatite coated PEEK for spinal fusion surgery.</a> Appl. Surf. Sci. 283, 6-11 (2013).</li><li>Johnson, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aerosol+Deposition+of+Yttrium+Iron+Garnet+for+Fabrication+of+Ferrite-Integrated+On-Chip+Inductors.">Aerosol Deposition of Yttrium Iron Garnet for Fabrication of Ferrite-Integrated On-Chip Inductors.</a> IEEE Trans. on Magnetics. 51 (05), (2015).</li><li>Johnson, S. D., Kub, F. J., Eddy, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ZnS/Diamond+Composite+Coatings+for+Infrared+Transmission+Applications+Formed+by+the+Aerosol+Deposition+Method.">ZnS/Diamond Composite Coatings for Infrared Transmission Applications Formed by the Aerosol Deposition Method.</a> Proceedings of SPIE. 8708, 87080T-87081T (2013).</li><li>Han, G., Ryu, J., Yoon, W. -. H., Choi, J. -. 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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+Thermoelectric+Properties+of+Textured+Ca3Co4O9+Thick+Film+by+Aerosol+Deposition.">Enhanced Thermoelectric Properties of Textured Ca3Co4O9 Thick Film by Aerosol Deposition.</a> J. Am. Ceram. Soc. 93 (8), 2125-2127 (2010).</li><li>Ryu, J., Kim, K. -. Y., Choi, J. -. J., Hahn, B. -. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+Dielectric+Bi1.5Zn1.0Nb1.5O7+Thin+Films+on+a+Cu-Polyimide+Foil.">Flexible Dielectric Bi1.5Zn1.0Nb1.5O7 Thin Films on a Cu-Polyimide Foil.</a> J. Am. Ceram. Soc. 92 (2), 524-527 (2009).</li><li>Hahn, B. -. D., Lee, J. -. M., Park, D. -. S., Choi, J. -. 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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+Photocatalytic+TiO2+Thin+Films+by+Aerosol+Deposition.">Porous Photocatalytic TiO2 Thin Films by Aerosol Deposition.</a> J. Am. Ceram. Soc. 93 (1), 55-58 (2010).</li><li>Harris, V. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+processing+and+applications+of+microwave+ferrites.">Recent advances in processing and applications of microwave ferrites.</a> J. of Magn. and Magn. Mat. 321, 2035 (2009).</li><li>Kang, Y. -. M., Ulyanov, A. N., Yoo, S. -. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FMR+linewidths+of+YIG+films+fabricated+by+ex+situ+post-annealing+of+amorphous+films+deposited+by+rf+magnetron+sputtering.">FMR linewidths of YIG films fabricated by ex situ post-annealing of amorphous films deposited by rf magnetron sputtering.</a> Phys. Stat. Sol. (a). 204 (3), 763-767 (2007).</li><li>Popova, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perpendicular+magnetic+anisotropy+in+ultrathin+yttrium+iron+garnet+films+prepared+by+pulsed+laser+deposition+technique).">Perpendicular magnetic anisotropy in ultrathin yttrium iron garnet films prepared by pulsed laser deposition technique).</a> J. of Vac. Sci. Techn. A. 19 (5), 2567-2570 (2001).</li><li>Sun, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+ferromagnetic+resonance+properties+of+nanometer-thick+yttrium.">Growth and ferromagnetic resonance properties of nanometer-thick yttrium.</a> Appl. Phys. Lett. 101 (15), 082405 (2012).</li><li>Kalarickal, S. S., Krivosik, P., Das, J., Kim, K. S., Patton, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwave+damping+in+polycrystalline+Fe-Ti-N+films:+Physical+mechanisms+and+correlations+with+composition+and+structure.">Microwave damping in polycrystalline Fe-Ti-N films: Physical mechanisms and correlations with composition and structure.</a> Phys. Rev. B. 77, 054427 (2008).</li><li>Johnson, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+Ferrite-Integrated+On-Chip+Inductors+Using+Aerosol+Deposition.">Advances in Ferrite-Integrated On-Chip Inductors Using Aerosol Deposition.</a> Magnetics Business &amp; Technology Magazine. 10, (2014).</li><li>Johnson, S. D., Glaser, E. R., Cheng, S. -. F., Kub, F., Eddy Jr, ., R, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+As-Deposited+and+Sintered+Yttrium+Iron+Garnet+Thick+Films+Formed+by+Aerosol.">Characterization of As-Deposited and Sintered Yttrium Iron Garnet Thick Films Formed by Aerosol.</a> Appl. Phys. Express. 7, 035501 (2014).</li><li>Lee, D. -. W., Nam, S. -. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+Affecting+Surface+Roughness+of+Al2O3+Films+Deposited+on+Cu+Substrates+by+an+Aerosol+Deposition+Method.">Factors Affecting Surface Roughness of Al2O3 Films Deposited on Cu Substrates by an Aerosol Deposition Method.</a> J. of Ceramic Proc. Research. 11, 100 (2010).</li><li>Glass, H. L., Elliott, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attainment+of+the+Intrinsic+FMR+Linewidth+in+Yttrium+Iron+Garnet+Films+Grown+by+Liquid+Phase+Epitaxy.J.">Attainment of the Intrinsic FMR Linewidth in Yttrium Iron Garnet Films Grown by Liquid Phase Epitaxy.J.</a> Cryst. Growth. 34, 285 (1976).</li></ol>

The SEM image in Figure 4 indicates that significant fracture and densification is occurring during the deposition process. The image is taken of the top surface of the film, which shows a small number of voids and grains. The observable region is the last of the material to be deposited and therefore does not benefit from the further impact and densification process of subsequent particles as illustrated by impact from particle 2 and 3 in Figure 1. The film density within the volume of ...

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk1. The deposition process is believed to occur through a continual process of impact, fracture or deformation, adhesion, and densification of particles. Figure 1 depicts this process as a series of steps showing particle impact and densification over several steps. As shown, the particles move toward the substrate with a typical velocity of 100&#8211;500 m/sec. As the initial particles impact with the substrate they fracture and adhere to the substrate. This anchoring layer provides the mechanical adhesion between the substrate and the bulk film. As subsequent impacts occur the underlying particles are increasingly fractured, adhered, and further densified. This process of continual impact, fracture, and densification works to compact the underlying film and bond the crystallites and produce a film with a density reaching greater than 95% of the bulk material.
<img alt="Figure 1" src="/files/ftp_upload/52843/52843fig1.jpg" /> 
Figure 1. Illustration of the deposition process. Panel A shows three particles moving toward the substrate with a typical velocity of 100&#8211;500&#160;m/sec. Panel B shows the result of impact, fracture, and adhesion of the first particle. Panels C and D show the subsequent impact of the second and third particles, which further compact the underlying film and bond the crystallites. The result is a film with density greater than 95% of the bulk material (reproduced with permission from Reference 19). <a href="https://www.jove.com/files/ftp_upload/52843/52843fig1highres.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The primary advantage of AD is that the deposition takes place entirely at ambient RT; thereby enabling film growth, for instance, of a high-melting-temperature material (starting powder) onto a low-melting-temperature substrate. The deposition rate can be up to several micrometers per minute and is performed at moderate vacuum conditions of 1&#8211;20 Torr in the deposition chamber. The process shows the ability to scale up to very large deposition areas and finally, it can deposit conformally.2
There are many material systems studied by AD for a wide variety of uses, such as inductors3, abrasion-resistant coatings4, piezoelectrics5, multiferroics6, magnetoelectrics7 thermistors8, thermoelectric films9, flexible dielectrics10, hard tissue implants and bioceramics11, solid electrolytes12, and photocatalysts13. For applications to microwave devices, magnetic films of several hundreds of micrometers in thickness are required that would ideally be integrated directly into the circuit board elements. One challenge to realizing this integration is the high-temperature regime needed for fabricating ferrite films (see review by Harris et al.14), such as yttrium iron garnet (YIG). For this reason AD appears to be a natural choice for realizing potential new advancements in magnetic integrated circuit technology. The low-cost operation, high deposition rate, and simplicity of AD has spurred interest by researchers in Germany, France, Japan, Korea, and now in the United States.
Figure 2 is a drawing outlining the basic setup to perform aerosol deposition. Pressure is monitored at the locations marked PAC, PDC, and PH for the aerosol chamber, deposition chamber, and pump head, respectively. The gas flow, controlled by the mass flow controller (MFC), enters the aerosol chamber and aerosolizes the powder. The deposition chamber is pumped to create the pressure difference between the two chambers, causing the flow of particles through the rectangular (0.4 mm x 4.8 mm) nozzle opening.
<img alt="Figure 2" src="/files/ftp_upload/52843/52843fig2.jpg" /> 
Figure 2. Main components in the NRL ADM system. Pressure is monitored at the locations marked PAC, PDC, and PH for the aerosol chamber, deposition chamber, and pump head, respectively. See text for details. (copyright (2014) The Japan Society of Applied Physics, reproduced from Reference 20). <a href="https://www.jove.com/files/ftp_upload/52843/52843fig2highres.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The average size of an individual YIG particle in this work is 0.5 &#181;m. The effect of agglomeration causes these small particles to form much larger agglomerates that range in size from about 10 &#181;m to about 400 &#181;m. Control of the agglomerate size and delivery rate is essential to achieving a dense well-formed film. This necessitates configuration of an aerosol chamber that allows size selection and uniform particle flux into the deposition chamber. The powder is pre-sieved to remove any agglomerates larger than 53 &#181;m prior to being loaded into the aerosol chamber. The aerosol chamber configuration used in this work is illustrated in Figure 3. Nitrogen gas enters through four inlet nozzles (two are shown in Figure 3) located at the bottom sides of the chamber. The gas interacts with the YIG powder (shown in green) to produce an aerosol comprised of a distribution of agglomerated particle sizes less than 53 &#181;m. An agitator at the base of the aerosol chamber made of a stainless steel plate is vibrated continuously to keep the powder moving into the gas flow. The agglomerates impact a 45 &#181;m filter, allowing only agglomerates sized less than 45 &#181;m to enter the nozzle inlet. Upon entering the nozzle inlet the agglomerates are accelerated to a large velocity and ejected into the deposition chamber (not shown) to perform the deposition. A stainless steel rod connects the bottom of the filter to the base of the agitator (not shown) to aid in de-clogging the filter.
<img alt="Figure 3" src="/files/ftp_upload/52843/52843fig3.jpg" /> 
Figure 3. Illustration of the internal aerosol chamber configuration, with filter, inlet nozzles, and YIG powder shown. See text for details.
This report details the experimental procedure to perform AD using the custom-built system described above to produce dense films of YIG. Representative results for an 11 &#181;m thick film produced in this system are presented using scanning electron microscopy (SEM), thickness profiles, and ferromagnetic resonance (FMR). The results presented are not intended to be an in-depth study of the magnetic properties or material structure of the film, but as a demonstration of the films produced by this technique. <a href="https://www.jove.com/files/ftp_upload/52843/52843fig3highres.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Ferromagnetic Resonance Spectrometer</td>
			<td>www.bruker.com/</td>
			<td>9.5 GHz Spectrometer</td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Electron Microscope</td>
			<td>www.zeiss.com</td>
			<td>LEO Supra 55</td>
			<td></td>
		</tr>
		<tr>
			<td>Profilometer</td>
			<td>www.kla-tencor.com/</td>
			<td>D-120</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Microscope</td>
			<td>www.microscopes.com</td>
			<td>Omano Stereo Microscope</td>
			<td>Used for inspection directly after removal from deposition chamber</td>
		</tr>
		<tr>
			<td>Double-sided Copper Tape</td>
			<td>www.2spi.com</td>
			<td>05085A-AB</td>
			<td>hold-down clips or other adhesives may be used</td>
		</tr>
		<tr>
			<td>Nitrile Exam Gloves</td>
			<td>www.fishersci.com</td>
			<td>19-130-1597D</td>
			<td></td>
		</tr>
		<tr>
			<td>2-propanol</td>
			<td>www.fishersci.com</td>
			<td>A451SK-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>www.fishersci.com</td>
			<td>A11-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Yttrium Iron Garnet Powder</td>
			<td>www.trans-techinc.com/</td>
			<td>Call for Product Information</td>
			<td>Powder is custom made to order and ground to specifications</td>
		</tr>
		<tr>
			<td>Stainless Steel Spoon</td>
			<td>www.fishersci.com</td>
			<td>14-429E</td>
			<td>Used for scooping and transferring powder</td>
		</tr>
		<tr>
			<td>Alumina Boats</td>
			<td>www.coorstek.com/</td>
			<td>65580</td>
			<td></td>
		</tr>
		<tr>
			<td>Drying Furnace</td>
			<td>www.paragonweb.com</td>
			<td>KM14 ceramic furnace</td>
			<td>Furnace is connected to air during drying</td>
		</tr>
		<tr>
			<td>Powder Sieves</td>
			<td>www.advantechmfg.com/</td>
			<td>270SS8F</td>
			<td>A selection of mesh openings are needed to sieve from large down to target size</td>
		</tr>
		<tr>
			<td>Ultra High Purity Nitrogen Gas</td>
			<td>www.praxairdirect.com</td>
			<td>NI 5.0UH-3K</td>
			<td>Used as medium for aerosol.</td>
		</tr>
		<tr>
			<td>Air Breathing Quality</td>
			<td>www.praxairdirect.com</td>
			<td>AI BR-4KN</td>
			<td>Used inside furnace during drying</td>
		</tr>
		<tr>
			<td>Lab Balance</td>
			<td>www.balances.com/</td>
			<td>Sartorius ED224S Lab Balance</td>
			<td>Used for weighing powder</td>
		</tr>
		<tr>
			<td>Sapphire Wafers</td>
			<td>www.pmoptics.com/</td>
			<td>PWSP-313211</td>
			<td></td>
		</tr>
	</tbody>
</table>

formation of thick dense yttrium iron garnet films using aerosol deposition

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 &#181;m thick yttrium iron garnet films that are &#160;&#62; 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

After the deposition is complete, the coated substrates are removed from the deposition chamber and inspected using an optical stereo microscope. Samples are typically brushed and washed with isopropanol to remove excess powder that remained during re-pressurization to atmosphere. Film characterization was performed on the representative results presented here using scanning electron microscopy to assess the morphology of the film, profilometry to assess the film thickness, uniformity, and roughness, and ferromagnetic re...

Watch this Scientific Journal Video about Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition at JoVE.com

Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition

This report describes the use of a custom-built system to perform aerosol deposition of thick films of yttrium iron garnet onto sapphire substrates at RT. The deposited films are characterized using scanning electron microscopy, profilometry, and ferromagnetic resonance to give a representative overview of the capabilities of the technique.

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% ...

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