A study of process conditions for plasma ion implantation hydrogenation experiments

Summary form only given, as follows. Plasma Ion Implantation (PII) hydrogenation has recently been found to be an effective method for defect passivation in thin film transistors (TFTs). PII process conditions can have a profound effect on dose rate and device reliability. Charge accumulation during the time of the pulse can damage the gate oxide and reduce the sheath electric field, decreasing the dose-rate and average implant energy. In order to minimize these effects, the pulse width must be kept short. The resulting decrease in the duty factor must be compensated by increasing the pulse repetition frequency if the dose rate is to remain constant. However, there is an upper limit on pulse repetition frequency imposed by ion depletion around the target. Plasma heating must be regulated to aid diffusion in the device without causing damage. Hydrogen etching can alter device structure and remove hydrogen already implanted. Based upon theory and experimental measurements of these factors, we have identified a window of process parameters to maximize PII hydrogenation process efficiency. We have calculated the minimum required PII process time for device parameter saturation.