Chemical vapor deposition and characterization of undoped and nitrogen-doped single crystalline 6H-SiC

Abstract

Homoepitaxial growth of single crystalline 6H-SiC layers is performed by chemical vapor deposition (CVD). 6H-SiC substrates are grown by a sublimation technique. They have vicinal surfaces inclined 1.5° to 2° from the (0001) plane towards the [11̄00] direction. We report CVD growth at 1600 °C in the hydrogen-silane-propane gas system with nitrogen as a dopant. High quality films are achieved with growth rates of about 1.8 μm per hour. The layers are examined by optical microscopy, infrared reflection, photoluminescence, and Rutherford backscattering. For electrical characterization capacitance-voltage and Hall measurements are performed. Unintentionally doped layers have donor concentrations in the upper 1015 cm−3 range. Electron mobilities of 370 cm2/V s at room temperature and about 104 cm2/V s at 45 K are observed. To the authors’ knowledge this is the highest mobility so far reported for 6H silicon carbide.