Embedded void approach effects on intrinsic stresses in laterally grown GaN-on-Si substrate

Abstract

Laterally grown GaN-on-Si substrate is promising for solid state lighting, high power density devices, and wireless communication applications among others. Despite their superior optical and electrical properties, they suffer from high dislocation-densities due to high lattice and thermal expansion coefficients mismatch between both crystalline materials. Different approaches have been suggested to reduce defects in GaN-on-Si technology. One of these approaches is Embedded Void Approach (EVA), which has been employed to control defects mobility in GaN thin-film on Si substrate by inserting micro-voids near the interface.In the current study, a three-dimensional multiple-slip crystal plasticity model and specialized finite-element formulations were used to address GaN growth on Si substrate. Furthermore, EVA has been studied to understand the effectiveness of the experimentally developed approach in reducing defects mobility. Additionally, a parametric study has been conducted to examine the effect of voids size and aspect ratio on the intrinsic stresses. It was found that EVA results in considerable reduction in the stresses in the mid surface of the structure near the voids and consequently the dislocation density at the top surface, enhancing the performance of the proposed system.