Size and etching effects on the reverse current of a-Si:H p-i-n diodes

The magnitude of the reverse dark current density (J(rev)) of p-i-n a-Si: H diodes depends on device geometry and on the etching technique used for device isolation. In the case of square-shaped devices Jrev has three components which originate in area, edge, and corner. These components are of the order of 4.0 x 10(-11) A/cm(2), 5.0 x 10(-12) A/cm, and 1.3 x 10(-13) A/corner, respectively, for devices patterned by reactive ion etching. For devices with areas below 4 x 10(-2) cm(2) the current density is dominated by the edge and corner components, which makes surface passivation important. When the deposition temperature of a-Si:H is raised from 250 to 400degreesC the three components increase by one order of magnitude. Wet etching results in lower leakage currents than dry etching. (C) 2003 The Electrochemical Society.