EFFECT OF HYDROGEN RADICALS ON PROPERTIES AND STRUCTURE OF A-SI1-XCX-H FILMS

We investigated the effect of hydrogen radicals on properties and stru cture of hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films by the use of a preparation system possessing both hydrogen plasma chamb er and silane/methane plasma chamber. The deposition rate, the carbon content, the optical band gap and the film structure investigated with IR transmission spectroscopy remained unchanged with changes in rf po wer on the hydrogen plasma side. However, the refractive index increas ed with increasing the rf power on the hydrogen plasma side. The Urbac h energy decreased from 67 to 53 meV. The photoconductivity of the fil ms prepared with the rf power on the hydrogen plasma side of 100 W was improved to be 3 x 10(-5) S cm(-1), which was by about two orders of the magnitude larger than that without hydrogen plasma. For preparing photoconductive a-Si1-xCx:H films, it is important to generate a numbe r of hydrogen radicals and introduce them onto the growing film surfac e efficiently. (C) 1998 Elsevier Science B.V. All rights reserved.