Using dual plasma treatment to improve electrical characteristics and reduce flicker noise of high-kappa HfO2 LTPS-TFTs

作者：Chang Kow Ming; Huang Bo Wen; Wu Chien Hung^*; Deng I Chung; Chang Ting Chia; Lin Sheng Chia

来源：Solid-State Electronics, 2015, 111: 7-11.

DOI：10.1016/j.sse.2015.03.017

• Dual plasma treatment
• LTPS-TFTs
• High-kappa metal gate
• Flicker noise

This study demonstrated the application of a dual plasma treatment to low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) comprising a self-aligned phosphorus implantation source and drain, high-kappa HfO2 gate dielectric, and aluminum metal gate. The dual plasma treatment involves a pre-deposition CF4 plasma treatment at a high-kappa/poly-Si interface and post-deposition N-2 plasma treatment at a high-kappa HfO2 gate dielectric; this treatment enables reducing the interface-trap-state defects at the high-kappa/poly-Si interface, grain boundary traps in the poly-Si channel film, and oxygen vacancy V-o in the high-kappa HfO2 gate dielectric. Thus, LTPS-TFTs with dual plasma treatment demonstrate excellent electrical characteristics such as threshold voltage, subthreshold swing, transconductance, driving current, and on/off current ratio. Flicker noise, also referred to as 1/f noise, caused by fluctuations of carriers transported in the grain boundary and the trapped carriers per unit oxide volume (N-t) can be suppressed. Therefore, high performance LTPS-TFTs subjected to dual plasma treatment can be appropriately applied to active matrix liquid phase-crystal display on system-on-panel technology.

• 出版日期2015-9