Title :
A novel two-step laser crystallization technique for low-temperature poly-Si TFTs
Author :
Zeng, Xiangbin ; Xu, Zhongyang ; Sin, Johnny K O ; Dai, Yongbin ; Wang, Changan
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., China
fDate :
5/1/2001 12:00:00 AM
Abstract :
We present investigations on a novel technique for preparing low-temperature poly-Si thin-film on glass substrates using two-step laser crystallization. In the first step, seeds are created by excimer laser induced crystallization of very thin (26 nm) amorphous silicon (a-Si) thin-films deposited by plasma enhanced chemical vapor deposition (PECVD). A second (a-Si) thin-film of 80-120 nm is used to obtain large crystalline grains grown around the seed crystallites during the second laser crystallization. Using this two-step crystallization (TSC) approach, we fabricated poly-Si thin-film transistors (TFTs) with electron mobility of 103 cm2/V·s and ON/OFF current ratio of 107. They are two times and four times higher than those of the poly-Si TFTs fabricated in the same run using conventional single-step excimer laser crystallization
Keywords :
electron mobility; elemental semiconductors; grain size; laser beam annealing; plasma CVD; recrystallisation annealing; silicon; thin film transistors; 2 to 6 nm; 80 to 120 nm; Si-SiN; electron mobility; excimer laser induced crystallization; glass substrates; large crystalline grains; low-temperature polysilicon TFTs; on/off current ratio; plasma enhanced chemical vapor deposition; second laser crystallization; seed crystallites; two-step laser crystallization technique; very thin amorphous Si thin films; Amorphous silicon; Chemical lasers; Chemical vapor deposition; Crystallization; Glass; Plasma chemistry; Semiconductor thin films; Sputtering; Substrates; Thin film transistors;
Journal_Title :
Electron Devices, IEEE Transactions on
