ELSEVIER Solar Energy Materials and Solar Cells 34 (1994) 379-384 so~ ~ k md Sa~t O¢~ Surface microstructures of ZnO coated SnO 2 • F films Toru Ikeda *, Kazuo Sato, Yasuo Hayashi, Yutaka Wakayama, Kunihiko Adachi, Hiromichi Nishimura Research Center, Asahi Glass Co., Ltd. 1150 Hazawa-cho, Kanagawa-ku, Yokohama 221, Japan Abstract ZnO films of 100 ,~ thick were coated on textured SnO 2 : F films using DC magnetron sputtering to improve hydrogen plasma durability: The surface microstructure and the plasma durability of the films were investigated using a scanning electron microscope (SEM), reflection high energy electron diffraction (RHEED) and optical measurements. It was found that the ZnO coated films exhibited high durability against hydrogen plasma. The well ordered microstructure of ZnO was considered to act as a good barrier against hydrogen diffusion into the SnO2 : F films. 1. Introduction SnO 2 TCO (transparent conductive oxide) films are well known as suitable electrodes for a-Si solar cells, because of favorable surface textures that enhance the conversion efficiency [1]. However, SnO 2 TCO films deteriorated when they were used under highly reducing conditions such as high substrate temperatures or an ECR plasma [2]. To prepare high quality a-Si layers under such conditions, durability improvements of TCO films are required. To overcome the problem, plasma resistant TCO films were developed by coating ZnO thin films of 100 A thick on textured SnO/:F films [3]. In this study, the relationship between a microstructure and hydrogen plasma durability of ZnO coated SnO2 : F film was investigated using SEM, RHEED, and optical measurements. * Corresponding author. 0927-0248/94/$07.00 © 1994 Elsevier Science B.V. All rights reserved SSDI 0927-0248(94)00055-W