OPTOELECTRONIC PROPERTIES OF HYDROGENATED AMORPHOUS-SILICON FILMS GROWN USING A MODIFIED PULSED PLASMA DISCHARGE

Hydrogenated amorphous silicon (a-Si:H) films were deposited by a modi fied pulsed plasma decomposition of silane and disilane in which a non zero low power level was maintained throughout the discharge. Depositi on rate (r(d)), optical band gap (E(g)), dark and photoconductivity (s igma(D) and sigma(ph)), and photosensitivity (sigma(ph)/sigma(D)) were investigated as a function of pulse parameters. By combining dwell ti me (tau) and the high power level (HPL) it has been shown that E(g) ca n be tailored over a fairly wide range. Similarly, sigma(D) and sigma( ph)/sigma(D) have been shown to depend, in addition to HPL, on tau as well, thereby proving the possibility of using tau as an additional pr ocess parameter. High band-gap a-Si:H material of quality (sigma(ph) = 4.4 X 10(-6) Omega(-1) cm(-1), sigma(ph)/sigma(D) approximate to 10(5 )) comparable to that of device quality a-Si:C:H has been deposited by this technique. (C) 1996 American Institute of Physics.