Mobility improvement of HfO2 LTPS-TFTs with nitrogen implanataion

Abstract

In this paper, we demonstrate the low-temperature polycrystalline silicon thin-film transistors (LTPS-TFrs) with high-k HfO2 gate dielectric and nitrogen implantation to achieve high-performance characteristics for the first time. Various nitrogen does 5 X 10(13) and 5 X 10(14) cm(-2) were implanted after gate dielectric deposition. Significant improvement 94.4% and 74.4% on transconductance G(m) and field effect mobility, respectively, are observed due to the nitrogen implantation. In addition, a substantial gate leakage current reduction over four orders is also obtained to decrease undesirable power dissipation. Finally, a high performance LTPS-TFT with low subthreshold swing 0.177 V/decade and threshold voltage about 1 V can be achieved without any other hydrogen plasma passivation treatments.