Comparative study of 4H-SiC DMOSFETs with N2O thermal oxide and deposited oxide with post oxidation anneal

• Two kinds of gate oxides, direct thermal oxidation in a nitrous oxide ambient at 1250°C (TGO) and a PECVD oxide followed by a post deposition oxidation in nitrous oxide ambient at 1150°C (DGO) were studied. DGO showed a lower interface trap density and was able to provide a higher current as being implemented in MOSFETs through the improved channel mobility. However the 6.45 MV/cm average breakdown field of DGO is lower than the 10.1 MV/cm breakdown field of TGO. The lower breakdown field, more leaky behavior and the existence of multiple breakdown mechanisms suggest that DGO needs further improvements before it can be used in real applications.

Nyckelord

4H-SiC

Deposited oxide

Mobility

MOSFET

Reliability

Carrier mobility

MOSFET devices

Nitrogen oxides

Oxidation

Breakdown mechanism

Comparative studies

Deposited oxides

Interface trap density

MOS-FET

Postdeposition oxidation

Real applications

Silicon carbide

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