Preparation of High Purity a-Si:H Films and Their Light Soaking Effects

Abstract

The preparation of high purity a-Si:H films is discussed in order to improve material quality and to reduce the Staebler-Wronski (S-W) effect. This letter presents the preparation technique and its relationship to the S-W, or light soaking effect. By using a hot-wall type symmetric-plasma CVD system and high rate deposition method, contaminant impurity levels in a-Si:H films are significantly reduced. Photoconductivity measurements of the films show that light soaking effects are reduced with oxygen content decreases to as low as 4×10¹⁷/cm³.