Enhanced Drain Current of 4H-SiC MOSFETs by Adopting a Three-Dimensional Gate Structure

Abstract

4H-SiC (0001) metal-oxide-semiconductor field-effect transistors (MOSFETs) with a 3-D gate structure, which has a top channel on the (0001) face and side-wall channels on the {112macr0} face, have been fabricated. The 3-D gate structures with a 1-5-mum width and a 0.8- mum height have been formed by reactive ion etching, and the gate oxide has been deposited by plasma-enhanced chemical vapor deposition and then annealed in N2O ambient at 1300degC. The fabricated MOSFETs have exhibited good characteristics: The I ON/I OFF ratio, the subthreshold swing, and V TH are 109, 210 mV/decade, and 3.5 V, respectively. The drain current normalized by the gate width is increasing with decreasing the gate width. The normalized drain current of a 1-mum-wide MOSFET is 16 times higher than that of a conventional planar MOSFET.