Investigation of Trenched and High Temperature Annealed 4H-SiC

Christian T. Banzhaf; Michael Grieb; Achim Trautmann; Anton J. Bauer; Lothar Frey

doi:10.4028/www.scientific.net/MSF.778-780.742

Paper Titles

Investigation of the Barrier Heights for Dissociative Adsorption of HF on SiC Surfaces in the Catalyst-Referred Etching Process
p.726

Hydrogen Effects in ECR-Etching of 3C-SiC(100) Mesa Structures
p.730

Off-Orientation Influence on C-Face (0001) 4H-SiC Surface Morphology Produced by Etching Using Chlorine Trifluoride Gas
p.734

Development of Silicon Carbide Dry Etcher Using Chlorine Trifluoride Gas
p.738

Investigation of Trenched and High Temperature Annealed 4H-SiC
p.742

Removal of Mechanical-Polishing-Induced Surface Damages on 4H-SiC Wafers by Using Chemical Etching with Molten KCl+KOH
p.746

Thinning of a Two-Inch Silicon Carbide Wafer by Plasma Chemical Vaporization Machining Using a Slit Electrode
p.750

A Novel Grinding Technique for 4H-SiC Single-Crystal Wafers Using Tribo-Catalytic Abrasives
p.754

Dicing of SiC Wafer by Atmospheric-Pressure Plasma Etching Process with Slit Mask for Plasma Confinement
p.759

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Investigation of Trenched and High Temperature Annealed 4H-SiC

Abstract:

This study focuses on the effects of a high temperature anneal after dry etching of trenches (post-trench anneal, PTA) on 4Hsilicon carbide (4H-SiC). We aim at the optimum 4H-SiC post-trench treatment with respect to the fabrication and the operation of a trenched gate metal oxide semiconductor field effect transistor (Trench-MOSFET). PTA significantly reduces micro-trenches, also called sub-trenches [, in the corners of the bottom of the trench. This is highly beneficial in case the etched trench sidewall is used as the channel of a Trench-MOSFET. However, PTA is also shown to cause a slight enlargement of the trench width along with a considerable increase of the substrate surface roughness. In addition, X-ray photoelectron spectroscopy (XPS) depth profiles indicate an increased carbon atom concentration at the 4H-SiC surface after the high temperature PTA. The non-stoichiometric surface composition affects the quasi-static capacitance-voltage (QSCV) behavior of MOS structures using a deposited gate oxide (GOX). We assume that a sacrificial oxidation directly after the PTA could restore a stoichiometric 4H-SiC surface.