Plasma Nitride Hydrogen Source Encapsulation Method to Hydrogenate Polysilicon Thin Film Transistors

摘要

A novel, commercially attractive process has beendeveloped to hydrogenate polysilicon thin film transistors (poly-Si TFTs). Active device regions TFTs are encapsulated by twonitride layers; one underneath the poly-Si channel but separatedby a thin oxide, and the other capping the device. During thedopant activation anneal, hydrogen is driven from nitride layers,through intermediate oxide layers, and into the channelpassivating trap sites. On test samples, secondary ion massspectroscopy suggests this treatment introduced up to 1020 cm-3hydrogen into poly-Si. After hydrogenation, the threshold wasreduced by 43 V and the saturation on-current improved by twomagnitudes, approaching the performance of electron cyclotronresonance hydrogenated TFTs.