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Influence Mechanism of Barium Interface Layer on the Interfacial Properties of n‐Type 4H‐SiC Metal–Oxide–Semiconductor Capacitors
Author(s) -
Bai Zhiqiang,
Tang Xiaoyan,
Zhang Yimeng,
Jia Yifan,
Jie Jiamin,
Song Qingwen,
Zhang Yuming
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000269
Subject(s) - passivation , materials science , x ray photoelectron spectroscopy , annealing (glass) , oxide , capacitor , barium , semiconductor , metal , equivalent oxide thickness , transition metal , layer (electronics) , analytical chemistry (journal) , optoelectronics , chemical engineering , nanotechnology , composite material , metallurgy , voltage , chemistry , gate oxide , electrical engineering , biochemistry , catalysis , transistor , chromatography , engineering
The 4H‐SiC/SiO 2 interface quality can be significantly improved by adding an alkaline earth metal interface layer. To study the passivation mechanism of the alkaline earth metal barium (Ba), a supercell model with a transition layer is established. As shown in the results from first‐principles calculations, the bandgap increases and the density of states decreases when SiBaO or OBaO structures are introduced into the transition layer. 4H‐SiC/Ba interface layer/SiO 2 capacitors with different annealing conditions are fabricated. X‐ray photoelectron spectroscopy results show that Ba mainly exists in the form of BaO 2 (corresponding to the OBaO structure) after annealing in 5% O 2 in Ar atmosphere, and there are fewer types of suboxides in the interface than those annealed in Ar. A small amount of Ba also combines with SiO 2 to form SiBa x O y compounds (corresponding to the SiBaO structure). The correctness of the theoretical analysis is verified by capacitance–voltage measurements. The physical mechanism of Ba passivation is analyzed in this article, which helps to improve the performance of SiC metal–oxide–semiconductor (MOS) structure devices.