Novel Poly-Si/GaN Vertical Heterojunction Diode

Abstract

We previously reported a unipolar mode p+-polycrystalline silicon (poly-Si)/4H-SiC heterojunction diode (SiC-HJD) [1-3]. In this work, we demonstrate a poly-Si/GaN vertical unipolar heterojunction diode (GaN-HJD) based on numerical simulation and experimental results. The GaN-HJD is expected to control the electrical characteristics of both Schottky action with a p-type poly-Si and ohmic action with an n-type poly-Si. We investigated the detailed physics of the GaN-HJD between p+ Si and n+ Si by numerical simulation. The GaN-HJD was also fabricated with p+-type polycrystalline silicon on an n--type epitaxial layer on bulk GaN substrates. The measured barrier height of the GaN-HJD was 0.79 eV and the ideality factor was 1.10.