| 摘要 |
An epitaxial film is formed on a substrate by a sputtering method. Sputtering is carried out by applying a bias voltage and a high frequency electric current for plasma generation to a target, and a bias voltage, and opt. a high frequency electric current to the substrate. During formation of the epitaxial film the ambient partial pressures of H2O, CO and CO2 are 1.0 x 10 power-8 Torr or less and the temp. of the substrate lies between 400 and 700 (pref. 500-600, esp. 500-550) deg.C. The growth of the epitaxial film is carried out in an atmos. supplied from an ultra-clean gas supply system or in a low-pressure atmos. generated using an oil-free ultra vacuum exhausting system. The frequency of the high frequency electric current applied to the substrate is higher than that applied to the target. The ultra clean gas comprises as major component Ar and/or He which contains 1 ppm or less of the impurity gases, H2O, CO and CO2. |
