Effect of Activation Annealing and Reactive Ion Etching on MOS Channel Properties of (11-20) Oriented 4H-SiC

Sauvik Chowdhury; Kensaku Yamamoto; T. Paul Chow

doi:10.4028/www.scientific.net/MSF.858.635

Paper Titles

Microscopic Difference between Dry and Wet Oxidations of C-Face 4H-SiC MOSFFETs Studied by Electrically Detected Magnetic Resonance
p.619

High Temperature Nitridation of 4H-SiC MOSFETs
p.623

Improvement of SiO₂/4H-SiC Interface Quality by Post-Oxidation Annealing in N₂ at High-Temperatures
p.627

Analytical Evaluation of Thermally Oxidized and Deposited Dielectric in NMOS-PMOS devices
p.631

Effect of Activation Annealing and Reactive Ion Etching on MOS Channel Properties of (11-20) Oriented 4H-SiC
p.635

Systematic Investigation of 4H-SiC Trench Properties Dependence on Channel Concentration, Crystallographic Plane, and MOS Interface Treatment
p.639

Influence of Oxide Processing on the Defects at the SiC-SiO₂ Interface Measured by Electrically Detected Magnetic Resonance
p.643

Investigation of the Interface Quality and Reliability of 4H-SiC MOS Structure with NO and Forming Gas Annealing Treatment
p.647

High Channel Mobility 4H-SiC MOSFETs by As and P Implantation Prior to Thermal Oxidation in N₂O Atmosphere
p.651

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Effect of Activation Annealing and Reactive Ion Etching on MOS Channel Properties of (11-20) Oriented 4H-SiC

Abstract:

In this paper we have investigated the effect of two key processing steps for the fabrication of 4H-SiC trench gate power MOSFETs, namely activation annealing and reactive ion etching on the MOS interface properties of a-face (11-20) 4H-SiC. By optimizing activation annealing conditions, high channel mobility (µ_fe) of 111 cm²/V.s, threshold voltage (V_T) of 3.5V and subthreshold slope (S) of 194 mV/dec was obtained. However, after reactive ion etching (RIE) of the surface, µ_fe reduced to 81 cm²/V.s with increase in V_T to 5V and S to 331 mV/dec. This is possibly due to increase in interface trap density from 1.8×10¹² cm^-2 to 3.3×10¹² cm^-2after RIE treatment estimated from by MOS gated diode characteristics. Increased trap density contributes to higher coulombic scattering as indicated by the weaker temperature dependence of high field mobility in RIE etched sample.