Study on geometry-dependent n⁺-InGaN regrowth via MOCVD for AlN/GaN ohmic contact application

This work investigates the impact of various geometries, suitable for ohmic regrowth applications, on the growth rate of n⁺-InGaN for AlN/GaN heterojunctions. In the various regrowth regions, we modelled the n⁺-InGaN growth rate by taking into account the diffusion effect of the growth source on the surrounding mask, using a surface migration-induced model. Additionally, we find that the peaks of n⁺-InGaN at the edge of the regrowth region, when higher than the surface of the SiO₂ mask, will significantly affect the diffusion of the growth source on the mask. The findings provide theoretical support for designing the growth thickness of n⁺-InGaN on different device structures with nonalloyed ohmic contacts via metal-organic chemical vapor deposition. Therefore, it can assist in determining the appropriate size of test structures, such as transmission line model and enhance the precision of n⁺ materials assessment on devices.