Prevention of Thin Film Failures for PECVD Amorphous-Si on Plastic Substrate

Amorphous silicon thin films were deposited below 160oC on PES plastic films using PECVD. After thin film deposition using PECVD, thin film failures such as film delamination and cracking often occurred. For successful growth of thin films (about 2000 Å) without their failures, it is necessary to solve the critical problem related to the internal compressive stress (some GPa) leading to delamination at a threshold thickness value of the films. The Griffith’s theory explains the failure process by looking at the excess of elastic energy inside the film, which overcomes the cohesive energy between film and substrate. In this work, reducing a-Si layer film thickness and optimizing a barrier SiNx layer have produced stable a-Si films at 150oC, over PES substrates.