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.