Current-induced instability in Cr-p(+) a-Si : H-V thin film devices

Experimental results on the constant current stressing in hydrogenated amor phous silicon (a-Si:H) Cr-p(+)-V thin film devices are presented. With incr easing injection of charge via either increasing bias or time. the current- voltage characteristics of devices exhibit instability, as shown by a decre ase in the reverse current. This is interpreted in terms of the creation of defects in the a-Si:H. The defect generation rate, as measured by the volt age shift Delta V at a constant reverse current in the J-V curve, is found to follow a square-root time dependent law. In addition, a decrease in devi ce conductance after stressing is also observed, which is described by a me chanism of dopant equilibrium during and after stressing.