Title :
Electrical characteristics of low temperature polysilicon TFT with a novel TEOS/oxynitride stack gate dielectric
Author :
Chang, Kow-Ming ; Yang, Wen-Chih ; Tsai, Chiu-Pao
Author_Institution :
Dept. of Electron. Eng., Nat. Chiao-Tung Univ., Hsinchu, Taiwan
Abstract :
This investigation is the first to demonstrate a novel tetraethylorthosilicate (TEOS)/oxynitride stack gate dielectric for low-temperature poly-Si (LTPS) thin film transistors (TFTs), composed of a plasma-enhanced chemical vapor deposition (PECVD) thick TEOS oxide/ultrathin oxynitride grown by PECVD N/sub 2/O-plasma. The stack oxide shows a very high electrical breakdown field of 8.4 MV/cm, which is approximately 3 MV/cm larger than traditional PECVD TEOS oxide. The field effective mobility of stack oxide LTPS TFTs is over 4 times than that of traditional TEOS oxide LTPS TFTs. These improvements are attributed to the high quality N/sub 2/O-plasma grown ultrathin oxynitride forming strong Si/spl equiv/N bonds, as well as to reduce the trap density in the oxynitride/poly-Si interface.
Keywords :
carrier mobility; dielectric thin films; elemental semiconductors; plasma CVD; semiconductor device breakdown; silicon; thin film transistors; Si; TEOS/oxynitride stack gate dielectric; electrical breakdown field; field effective mobility; low temperature polysilicon TFT; plasma-enhanced chemical vapor deposition; tetraethylorthosilicate; thin film transistors; trap density; ultrathin oxynitride; Active matrix liquid crystal displays; Circuits; Dielectric thin films; Electric breakdown; Electric variables; Oxidation; Plasma applications; Plasma temperature; Substrates; Thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2003.815155
