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Title: Deposition of sputtered NiO as a p-type layer for heterojunction diodes with Ga 2 O 3
The characteristics of sputtered NiO for use in pn heterojunctions with Ga 2 O 3 were investigated as a function of sputtering parameters and postdeposition annealing temperature. The oxygen/ nickel and Ni 2 O 3 /NiO ratios, as well as the bandgap and resistivity, increased as a function of O 2 /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 O 2 /Ar ratio increasing from 1/30 to 1/3. By sharp contrast, the bandgap and Ni 2 O 3 /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-Ga 2 O 3 . The breakdown voltage of NiO/β-Ga 2 O 3 heterojunction rectifiers was also a strong function of the O 2 /Ar flow ratio during deposition, with values of 1350 V for 1/3 and 830 V for 1/30.  more » « less
Award ID(s):
1856662
PAR ID:
10387878
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Vacuum Science & Technology A
Volume:
41
Issue:
1
ISSN:
0734-2101
Page Range / eLocation ID:
013405
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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