Effect of Atomic Hydrogen in SiNx Films for Gate Dielectric of Silicon-Based TFTs Fabricated at a Low-Temperature(≤150 °) by Cat-CVD

Abstract

We studied the effect of in-situ hydrogen annealing on dielectric SiNx films at a low-temperature (150 oC) by Cat-CVD. The in-situ hydrogen annealing was performed without a vacuum breaking. After in-situ annealing, furnace annealing was performed for 2hours below 150 oC. The C-V, and I-V characteristics were measured by MIS structure. The high hydrogen ratio sample showed better dielectric properties improvement by annealing. SiNx films dielectric properties were extremely improved by in-situ hydrogen annealing and furnace annealing. Breakdown field was 6 MV/cm. C-V hysteresis window was reduced from 15 V to 1 V. The on/off ratio of TFT was 105. The Mobility was 0.23. We successfully fabricated dielectric SiNx films at the low temperature, and also a-Si TFTs at the same temperature by Cat-CVD.