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Please use this identifier to cite or link to this item: http://www.lib.ncsu.edu/resolver/1840.16/4551

Title: GaN-dielectric interface formation for gate dielectrics and passivation layers using remote plasma processing
Authors: Bae, Choelhwyi
Advisors: Gerald Lucovsky, Committee Co-Chair
Keywords: interface
passivation
SiO2
MOS
gate dielectric
GaN
Issue Date: 3-Jul-2003
Degree: PhD
Discipline: Electrical Engineering
Abstract: In previous studies, device quality Si-SiO2 interfaces and dielectric bulk films (SiO2) were prepared using a two-step process; i) remote plasma-assisted oxidation (RPAO) to form a superficially interfacial oxide (~0.6 nm) and ii) remote plasma enhanced chemical vapor deposition (RPECVD) to deposit the oxide film. The same approach has been applied to the GaN-SiO2 system. After a 300 oC remote N2/He plasma treatment of the GaN surface, residual C and Cl were reduced below Auger electron spectroscopy (AES) detection, and the AES peak ratio of O KLL and N KLL was ~0.06 or ~0.1 monolayer of oxygen. RPAO of GaN surfaces using O2, N2O, and N2O in N2 source gases were investigated by on-line AES to determine the oxidation kinetics and chemical composition of the interfacial oxide. Without an RPAO step, subcutaneous oxidation of GaN takes place during RPECVD deposition of SiO2, and on-line AES indicates a ~0.6-0.8 nm subcutaneous oxide. Compared to single step SiO2 deposition, significantly reduced interface state density (Dit) was obtained at the GaN-SiO2 interface by independent control of GaN-Ga2O3 interface formation by thin RPAO oxide (~1 nm) and SiO2 film deposition by RPECVD. High-low frequency method and conductance method indicate that Dit of GaN Metal-Oxide-Semiconductor (MOS) sample without RPAO is ~5 times larger than that of the sample with RPAO. For the GaN MOS structure with remote plasma oxidation and nitridation, Dit determined at DCmax was low-to-mid x 1011 cm-2eV-1. Also, we report on high temperature and photo-assisted capacitance-voltage (C-V) characteristics.
URI: http://www.lib.ncsu.edu/resolver/1840.16/4551
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