Theoretical prediction of a self-forming gallium oxide layer at an n-type GaN/SiO₂interface

Abstract

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.

The Influence of Ga–OH Bond at Initial GaN Surface on the Electrical Characteristics of SiO2/GaN Interface

“…The formation of a Ga oxide layer at the SiO 2 /GaN interface layer has also been observed . After depositing the SiO 2 layer by PECVD with tetraethyl orthosilicate (TEOS) gas and O 2 plasma, a 1.5 nm‐thick Ga 2 O 3 phase formed at the SiO 2 /GaN interface .…”

Generating robust two-dimensional hole gas at the interface between boron nitride and diamond

“…All the density-functional-theory calculations are carried out by using the Vienna ab initio Simulation Package. [26][27][28] The electronic properties of these c-BN/diamond(001) heterostructure systems are calculated by Heyd, Scuseria, and Ernzerhof hybrid function with a screening parameter of 0.25 Å −1 and a nonlocal Fock-exchange parameter of 0.40, 29) which produces the band gap values of 5.48 eV and 5.95 eV for bulk diamond and c-BN, respectively. The values are close to the experimental values of 5.47 eV for diamond 30) and 6.20 eV for c-BN.…”

Self-forming and self-decomposing gallium oxide layers at the GaN/Al2O3 interfaces

“…31) In previous work, we proposed a mechanism for the formation of the Ga 2 O 3 interlayer at an n-type GaN (n-GaN)/SiO 2 interface. 32) In this mechanism, electron transfer from n-GaN to SiO 2 and the formation of oxygen vacancy (V O ) defects in the SiO 2 induced an energy gain, causing interfacial oxidation and resulting in the spontaneous formation of Ga 2 O 3 . As in the case of GaN/SiO 2 interfaces, we guess that there are some mechanisms by which a Ga 2 O 3 interlayer spontaneously can be formed at a GaN/Al 2 O 3 interfaces.…”

“…In our previous work, we proposed interfacial reaction mechanism induced by the V O defect formation at the n-GaN/SiO 2 interfaces. 32) However, since formation energy of the V O defects in Al 2 O 3 is very large, such the interfacial reaction do not occur at the n-GaN/Al 2 O 3 interfaces. Thus, although the V O defects are very important, they do not cause different interfacial reactions for both p-GaN and n-GaN.…”