Deposition of sputtered NiO as a p-type layer for heterojunction diodes with Ga2O3
Abstract
The characteristics of sputtered NiO for use in pn heterojunctions with Ga2O3 were investigated as a function of sputtering parameters and postdeposition annealing temperature. The oxygen/ nickel and Ni2O3/NiO ratios, as well as the bandgap and resistivity, increased as a function of O2/Ar gas flow ratio. For example, the bandgap increased from 3.7 to 3.9 eV and the resistivity increased from 0.1 to 2.9 Ω cm for the O2/Ar ratio increasing from 1/30 to 1/3. By sharp contrast, the bandgap and Ni2O3/NiO ratio decreased monotonically with postdeposition annealing temperatures up to 600 °C, but the density of films increased due to a higher fraction of NiO being present. Hydrogen is readily incorporated into NiO during exposure to plasmas, as delineated by secondary ion mass spectrometry measurements on deuterated films. The band alignments of NiO films were type II-staggered gaps with both α- and β-Ga2O3. The breakdown voltage of NiO/β-Ga2O3 heterojunction rectifiers was also a strong function of the O2/Ar flow ratio during deposition, with values of 1350 V for 1/3 and 830 V for 1/30.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 27, 2022
- Source ID
- 10.1116/6.0002250
Entities
People
- Brent P. Gila
- Chao-Ching Chiang
- David C. Hays
- Fan Ren
- Jian-Sian Li
- Stephen Pearton
- Valentin Crăciun
- Xinyi Xia
Organizations
- Defense Threat Reduction Agency
- Extreme Light Infrastructure
- Ministry of Education of Romania
- National Science Foundation
- University of Florida