monolayer-contact-doping-silicon-surfaces-nanowires-using

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

The Hebrew University of Jerusalem

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Contact doping method for the controlled surface doping of silicon wafers and nanometer scale structures is presented. The method, monolayer contact doping (MLCD), utilizes the formation of a dopant-containing monolayer on a donor substrate that is brought to contact and annealed with the interface or structure intended for doping. A unique feature of the MLCD method is that the monolayer used for doping is formed on a separate substrate (termed donor substrate), which is distinct from the interface intended for doping (termed acceptor substrate). The doping process is controlled by anneal conditions, details of the interface, and molecular precursor used for the formation of the dopant-containing monolayer. The MLCD process does not involve formation and removal of SiO(2) capping layer, allowing utilization of surface chemistry details for tuning and simplifying the doping process. Surface contact doping of intrinsic Si wafers (i-Si) and intrinsic silicon nanowires (i-SiNWs) is demonstrated and characterized. Nanowire devices were formed using the i-SiNW channel and contact doped using the MLCD process, yielding highly doped SiNWs. Kelvin probe force microscopy (KPFM) was used to measure the longitudinal dopant distribution of the SiNWs and demonstrated highly uniform distribution in comparison with in situ doped wires. The MLCD process was studied for i-Si substrates with native oxide and H-terminated surface for three types of phosphorus-containing molecules. Sheet resistance measurements reveal the dependency of the doping process on the details of the surface chemistry used and relation to the different chemical environments of the P═O group. Characterization of the thermal decomposition of several monolayer types formed on SiO(2) nanoparticles (NPs) using TGA and XPS provides insight regarding the role of phosphorus surface chemistry at the SiO(2) interface in the overall MLCD process. The new MLCD process presented here for controlled surface doping provides a simple yet highly versatile means for achieving postgrowth doping of nanometer scale structures and interfaces.

Contact doping of silicon wafers and nanostructures with phosphine oxide monolayers.

More than they appear on the surface: The treatment of SiO2 nanoparticles under mild conditions with two organoboron derivatives led to boron-containing monolayers with different types of surface species (see picture) through the direct formation of Si-O-B bonds. The organoboron-modified SiO2 NPs showed selective reactivity towards diols.

Arunava Agarwala

Institute of Chemistry,
Center for Nanoscience and Nanotechnology

The Hebrew University of Jerusalem

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Arunava Agarwala

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute of Chemistry,Center for Nanoscience and Nanotechnology

The Hebrew University of Jerusalem

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Institute of Chemistry,
Center for Nanoscience and Nanotechnology