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Title: Band alignment of sputtered and atomic layer deposited SiO 2 and Al 2 O 3 on ScAlN
The band alignments of two candidate dielectrics for ScAlN, namely, SiO 2 and Al 2 O 2 , were obtained by x-ray photoelectron spectroscopy. We compared the effect of deposition method on the valence band offsets of both sputtered and atomic layer deposition films of SiO 2 and Al 2 O 3 on Sc 0.27 Al 0.73 N (bandgap 5.1 eV) films. The band alignments are type I (straddled gap) for SiO 2 and type II (staggered gap) for Al 2 O 3 . The deposition methods make a large difference in relative valence band offsets, in the range 0.4–0.5 eV for both SiO 2 and Al 2 O 3 . The absolute valence band offsets were 2.1 or 2.6 eV for SiO 2 and 1.5 or 1.9 eV for Al 2 O 3 on ScAlN. Conduction band offsets derived from these valence band offsets, and the measured bandgaps were then in the range 1.0–1.1 eV for SiO 2 and 0.30–0.70 eV for Al 2 O 3 . These latter differences can be partially ascribed to changes in bandgap for the case of SiO 2 deposited by the two different methods, but not for Al 2 O 3 , where the bandgap as independent of deposition method. Since both dielectrics can be selectively removed from ScAlN, they are promising as gate dielectrics for transistor structures.  more » « less
Award ID(s):
1856662
PAR ID:
10385645
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Applied Physics
Volume:
132
Issue:
23
ISSN:
0021-8979
Page Range / eLocation ID:
235701
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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