Effects of rf-Bias on Properties of Sputtered Silicon Films

Amorphous silicon films were prepared by rf-bias sputtering with a magnetron target and the effects of substrate bias on the electrical and optical properties of sputtered films were studied. Moderate substrate bias was found to improve film quality: photoconductivity increased to ∼2×10-4 \mho/cm and the spin density decreased to ∼4×1017 cm-3 for the biased samples. The results are interpreted in terms of the removal of loosely bound materials from the surface by ion-bombardment. Low voltage sputtering due to the magnetron target in high argon pressure would also play some roles in the improvement of film quality.