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

Abstract

4H-SiC (0001) metal-oxide-semiconductor fieldeffect transistors (MOSFETs) with a 3-D gate structure, which has a top channel on the (0001) face and side-wall channels on the {1120} face, have been fabricated. The 3-D gate structures with a 1-5-µm width and a 0.8-µm 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 N 2 O ambient at 1300 • C. The fabricated MOSFETs have exhibited good characteristics: The I ON /I OFF ratio, the subthreshold swing, and V TH are 10 9 , 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-µm-wide MOSFET is 16 times higher than that of a conventional planar MOSFET.

4H-SiC MOS Capacitors and MOSFET Fabrication with Gate Oxidation at 1400°C

“…The high temperature oxidation aims to enhance the oxidation rate of carbon relative to that of silicon in 4H-SiC. The enhanced oxidation rate is expected to reduce the interface states at the 4H-SiC/SiO 2 interface attributed to the carbon clusters at the interface due to incomplete oxidation because of slow thermal oxidation rates for 4H-SiC [7]. Dry oxidation process was used instead of wet oxidation due to lower oxide charges in dry oxidation process.…”

Progress and future challenges of silicon carbide devices for integrated circuits

“…In order to overcome the low channel mobility of SiC MOSFETs, a three-dimensional (3D) gate structure has been investigated [29]. The schematic illustration of the 3D-gate structure is shown in Fig.7 (a).…”

3D structures for silicon carbide transistors utilising Al2O3 as a gate dielectric

“…An enhanced drain current has been demonstrated by the use of a 3-D gate structure power MOSFET owing to the anisotropic mobility properties of 4H-SiC on different planes. This indicates that the development of 3-D structures offers a route to high performance nano -scale devices that are capable of operating in high temperature environments, because 3-D gate MOSFETs have better control of short channel effects [18,19].…”