Oxygen Pressure Controlled Oxidation for Gate Insulator Process of SiC MOSFETs
For the improvement of a SiC/SiO2 interface of SiC-MOSFET, we examined O2 partial pressure (PO2) controlled (OPC) oxidation process for the gate oxide formation. The OPC oxidation process has a potential to reduce interface state density (Dit) at SiC/SiO2 interface by using appropriate PO2 and oxidation temperature. However the process requires rapid thermal annealing which is not suitable for mass production. Thus we investigated the process using furnace. First, we optimized the OPC oxidation process for the furnace to realize low interface defect density. Secondly, we confirmed that reduction of Dit was determined by desorption of excess carbon in OPC process by the C–ψs measurement and X-ray photoelectron spectroscopy. Finally, a DMOSFET was fabricated using optimized OPC process. We measured the transfer characteristics, and found that the drain current with OPC was larger than without OPC process.
Robert Stahlbush, Philip Neudeck, Anup Bhalla, Robert P. Devaty, Michael Dudley and Aivars Lelis
K. Kobayashi et al., "Oxygen Pressure Controlled Oxidation for Gate Insulator Process of SiC MOSFETs", Materials Science Forum, Vol. 924, pp. 453-456, 2018