Fabrication and Characterization of 4H-SiC MOSFET with MOCVD-Grown Al2O3 Gate Insulator
We have fabricated and characterized MOS capacitors and lateral MOSFETs using Al2O3 as a gate insulator. Al2O3 films were deposited by metal-organic chemical vapor deposition (MOCVD) at temperatures as low as 190 oC using tri-ethyl-aluminum and H2O as precursors. We first demonstrate from the capacitance – voltage (C-V) measurements that the Al2O3/SiC interface has lower interface state density than the thermally-grown SiO2/SiC interface. No significant difference was observed between X-ray photoelectron spectroscopy (XPS) Si 2p spectrum from the Al2O3/SiC interface and that from the SiC substrate, which means the SiC substrate was not oxidized during the Al2O3 deposition. Next, we show that the fabricated lateral SiC-MOSFETs with Al2O3 gate insulator have good drain current – drain voltage (ID-VD) and drain current – gate voltage (ID-VG) characteristics with normally-off behavior. The obtained peak values of field-effect mobility (μFE) are between 68 and 88 cm2/Vs.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
S. Hino et al., "Fabrication and Characterization of 4H-SiC MOSFET with MOCVD-Grown Al2O3 Gate Insulator ", Materials Science Forum, Vols. 556-557, pp. 787-790, 2007