Influence of Silicon Nanostructures on the Growth of GaN on Silicon

Abstract

GaN is an important III-V semiconductor with several device applications, such as LEDs, LDs and HEMTs. Silicon, being cost-effective, is becoming a more common substrate for GaN growth. However, intrinsic differences between the two materials create integration problems. As nanostructured substrate is known to induce better crystal quality through nanoheteroepitaxy, an investigation on how silicon nanostructures can influence the subsequently grown GaN was done using MOCVD. One-step metal-assisted chemical etching (MACE) was the chosen nanofabrication technique. In this thesis, a systematic study was done to optimize the fabrication of silicon nanostructures. Thereafter, silicon wafers were processed using the optimized conditions and then used as substrates for GaN growth. Different growth sequences were investigated to determine the most suitable process for film growth. Finally, GaN grown on nanostructured silicon and flat silicon were characterized by several techniques for comparisons.