O-2-plasma passivation effects on polysilicon thin film transistors using ion plating method

Abstract

A novel method has been developed for efficiently reducing defect density in polysilicon thin film transistors using ion plated oxides as capping layers. The characteristics of these novel thin film transistors are superior to those of thin film transistors with plasma-enhanced chemical vapor deposited tetraethylorthosilicate capping oxides due to an in situ O-2-plasma passivation effect during ion plating oxide deposition. The passivation effect of a NH3 plasma on the novel devices was also studied. The in situ ion plating O-2 plasma shows a better passivation efficiency on trap states than the NH3 plasma. Polysilicon thin film transistors with ion plating capping oxides are hardly degraded even when stressed with a bias of 20 V at 100 degrees C.