Novel Technical Approach to Produce III-N Sample Libraries

TDI proposes to produce combinatorial GaN and AlGaN samples library having a wide range of doping and fabricated using a variety of surface treatment conditions. These samples will be grown using novel technological approach based on advanced hydride vapor phase epitaxy (HVPE). This method is known to produce bulk GaN materials with low defect density. Recently, TDI has demonstrated high throughput HVPE growth for both (1) doped GaN and AlGaN layers and (2) undoped layers with record low background impurity concentrations. These results opened an opportunity to develop GaN and AlGaN samples library to optimize material sheet resistivity and minimize ohmic contact resistivity using a multi-parameter space experiments. Phase I project is focused on HVPE growth of n-type and p-type samples having wide doping range and investigation of several metallization schemes for ohmic contact fabrication. Unique ability of HVPE to control defect formation in grown layers will allow us to investigate defect influence on sheet resistivity and contact resistance. The main goal of the Phase I is to prove the concept and demonstrate p- and n-type GaN and AlGaN materials with continues and discrete variation in sheet resistivity. Novel sample preparation schemes allowing combinatorial experiments on samples produced under the same conditions are proposed. Doping in grown layers will be varied from 5x1015 to 1x1020 cm-3. Fabricated samples will be delivered to NIST for testing and evaluation. COMMERCIAL APPLICATIONS: Optimization of ohmic contacts for GaN and AlGaN materials is very important for design, development and commercialization of a variety of GaN-based devices for both electronic and optoelectronic applications. Thermally stable low-resistance ohmic contacts to n- and p-type GaN and AlGaN materials will find a host of applications for GaN-based devices and will leverage commercialization of advanced devices such as blue and ultra-violet laser diodes and high power high frequency transistors. Tremendous commercial potential is projected for solid-state lighting devices, which also require low-resistivity ohmic contact to GaN and AlGaN materials.