Mechanisms of Nitrogen Incorporation at 4H-SiC/SiO2 Interface during Nitric Oxide Passivation – A First Principles Study

Devanarayanan Ettisserry; Neil Goldsman; Akin Akturk; Aivars J. Lelis

doi:10.4028/www.scientific.net/MSF.858.465

Paper Titles

Characterization of Thermally Oxidized SiO₂/SiC Interfaces by Leakage Current under High Electric Field, Cathode Luminescence (CL), X-Ray Photoelectron Spectroscopy (XPS) and High-Resolution Rutherford Backscattering Spectroscopy (HR-RBS)
p.449

Dipole Type Behavior of NO Grown Oxides on 4H–SiC
p.453

Importance of SiC Stacking to Interlayer States at the SiC/SiO₂ Interface
p.457

Measurement Issues Affecting Threshold-Voltage Instability Characterization of SiC MOSFETs
p.461

Mechanisms of Nitrogen Incorporation at 4H-SiC/SiO₂ Interface during Nitric Oxide Passivation – A First Principles Study
p.465

Nondestructive and Local Evaluation of SiO₂/SiC Interface Using Super-Higher-Order Scanning Nonlinear Dielectric Microscopy
p.469

On the Origin of Threshold Voltage Instability under Operating Conditions of 4H-SiC n-Channel MOSFETs
p.473

Pragmatic Approach to the Characterization of SiC/SiO₂ Interface Traps near the Conduction Band with Split C-V and Hall Measurements
p.477

Threshold Voltage Instabilities of Present SiC-Power MOSFETs under Positive Bias Temperature Stress
p.481

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Mechanisms of Nitrogen Incorporation at 4H-SiC/SiO₂ Interface during Nitric Oxide Passivation – A First Principles Study

Abstract:

In this work, we investigate the behavior of Nitrogen atoms at 4H-Silicon Carbide (4H-SiC)/Silicon dioxide (SiO₂) interface during nitric oxide passivation using ab-initio Density Functional Theory. Our calculations suggest different possible energetically favorable and competing mechanisms by which nitrogen atoms could a) incorporate themselves into the oxide, just above the 4H-SiC substrate, and b) substitute for carbon atoms at the 4H-SiC surface. We attribute the former process to cause increased threshold voltage instability (hole traps), and the latter to result in improved effective mobility through channel counter-doping, apart from removing interface traps in 4H-SiC power MOSFETs. These results support recent electrical and XPS measurements. Additionally, Nitric Oxide passivation is shown to energetically favor re-oxidation of the 4H-SiC surface accompanied by the generation of oxygen vacancies under the conditions considered in this work.