Thermal Oxidation of Sputtered Silicon Carbide Thin Films

The physical properties and oxidation behavior of silicon carbide thin films are reported. These films were RF sputtered from a composite target of stoichiometric proportion onto thermally oxidized silicon substrates. The refractive index of the carbide films, after annealing at 1100°C in hydrogen, was very close to the bulk value of 2.65. Structural and compositional properties were studied by Rutherford backscattering spectrometry, secondary ion mass spectrometry, and x‐ray diffraction techniques. Thermal oxidation was carried out in wet and dry oxygen at 900°–1100°C for a period of up to 16h. Depending on the temperature and time period, the oxidation rate of silicon carbide was about 2–11 times slower than that of single‐crystal (100) Si. The oxide layer grown out of the carbide films was determined to be silicon oxide. The average activation energy for wet and dry oxidation was calculated to be 50 and 43.5 kcal/mol, respectively. The patterning of the SiC films was investigated using CF 4 / O 2 and NF 3 plasmas. “Bird's beak” profiles, obtained upon field oxidation of SiC / SiO 2 / Si structures, were studied.