Reduction of Threading Dislocation by Using Pattern Sapphire Substrate on GaN to Enhance Schottky Diode's Performance

Abstract

AlGaN/GaN heterojunction is a well-known material because of its large critical electric field and high chemical stability. There's a lots of applications such as LED, optical devices, high-frequency transistor, etc. Therefore, we can use this material to fabricate high-power and high-frequency device. Nowadays, more groups are interesting on GaN and claim it may become a good candidate of replacing Silicon. In this study, we used pattern sapphire substrate (PSS) technol-ogy to growth high-quality GaN thin film by MOCVD and manu-facturing AlGaN/GaN Schottky diode. We believed that PSS technology can magnificently improve the quality of GaN thin film and it has been proved by Raman spectrum and etch pit density (EPD). We also design different dimension to gain the lower defect density and better electrical performance Schottky diode. We successfully reduce etching pits density from 3.87x106 (cm-2) to 1.37x106 (cm-2) and FWHM of Raman spectrum from 2.46 (cm-1) to 2.33 (cm-1) by using our PSS technology. Meanwhile, we reduced Schottky contact resistivity from 0.0657(Ωcm2) to 0.00266(Ωcm2).