Thermal stability of sputtered TiN as metal gate on 4H-SiC

MOS-structures were made with TiN as metal gate on 4H-SiC. The thermal stability and electrical properties of this gate was determined by CV-measurements. Comparison with Al gates showed that TIN worked well as a gate metal on 4H-SiC. The hysteresis and density of the interface states were comparable for the two gate types. The n-type samples had low leakage and a flatband voltage of a few volts, while the p-type samples I lad high leakage and a flatband voltage of around -20 V. The structure showed poor characteristics after a 700 degrees C anneal for one hour, which is probably caused by the formation of titanium silicode. The TiN films had a lower content of nitrogen than expected, which could influence the stability.