Theoretical prediction of a self-forming gallium oxide layer at an n-type GaN/SiO2 interface

• Published in: Applied physics express 2018-03, Vol.11 (3)
• Main Authors: Chokawa, Kenta, Narita, Tetsuo, Kikuta, Daigo, Kachi, Tetsu, Shiozaki, Koji, Shiraishi, Kenji
• Format: Article
• Language: English
• ISSN: 1882-0778; 1882-0786
• DOI: 10.7567/APEX.11.031002

We examine the energy band diagram at the n-type GaN (n-GaN)/SiO2 interface and show that electron transfer from n-GaN to SiO2 leads to the formation of negatively charged oxygen vacancies in the SiO2, resulting in the self-formation of an n-GaN/Ga2O3/SiO2 structure. On the other hand, it is difficult to automatically form Ga2O3 at a p-type GaN (p-GaN)/SiO2 interface. This electron-transfer-induced self-formation of Ga2O3 causes an interface dipole, which leads to band bending, resulting in an increase in the conduction band offset between GaN and SiO2. Accordingly, by using this self-forming phenomenon, GaN MOSFETs with lower leakage current can be realized.