Mechanical Bending Cycles of Hydrogenated Amorphous Silicon Layer on Plastic Substrate by Plasma-Enhanced Chemical Vapor Deposition for Use in Flexible Displays

Abstract

Atomic force microscopy (AFM) measurements and micro-Raman spectra show that the long-range hydrogenated amorphous silicon (a-Si:H) bond structure on a plastic substrate is deformed and distorted after being subjected to bending cycles, whereas the short-range a-Si:H bond structure remains the same. The disordered bonds may generate a redistribution of trap states, resulting in unstable electrical characteristics such as threshold voltage, subthreshold swing, and mobility of carriers. From AFM and micro-Raman spectroscopy, we are able to understand the morphology of an a-Si:H layer under mechanical strain, which is the fundamental reliability issue for the development of flexible electronics. (C) 2009 The Japan Society of Applied Physics