Performance of a-Si:H thin film transistors fabricated by very high frequency discharge silane plasma chemical vapor deposition

This paper discusses the dependence of a-Si:H thin film transistor (TFT) performance on the plasma excitation frequency for a-Si:H film deposition. We studied the effects of the plasma excitation frequency over the range of 13.56-50 MHz, altering the deposition rate under various conditions. At the conventional 13.56 MHz frequency, the field effect mobility value decreases to 0.19 cm(2)V(-1)s(-1) at a deposition rate of 76 nm/min. As the excitation frequency increases, the rate of mobility drop to the deposition rate decreases in the high rate deposition region. A mobility value as high as 0.30 cm(2)V(-1)s(-1) can be obtained at a high deposition rate of 130 nm/min using a 50 MHz frequency.