Comparison of the hydrogenation techniques on polysilicon TFTs

Hydrogenation is a key technique to improve the electrical performances of the polysilicon thin film transistors (TFT). However, the modifications of the electrical properties strongly depend on the techniques of hydrogenation. Usually, hydrogen passivation of polysilicon films is performed using RF plasma of hydrogen (1) or by the use of silicon nitride films deposited by plasma enhanced chemical vapor deposition (PECVD) on the polysilicon TFT (2). However, a new technique of hydrogenation based on the electron-cyclotron resonance plasma (ECR) is under investigation in several laboratories (3). In this paper, early electrical results on the hydrogenation of polysilicon TFTs using a new microwave plasma technique which does not use a magnetic field as the ECR technique is presented and compared with those obtained with the silicon nitride passivation technique