Behavior of the drain leakage current in metal-induced laterally crystallized thin film transistors

Ni-metal-induced crystallization (MIC) of amorphous Si (a-Si) has been employed to fabricate low-temperature polycrystalline silicon thin-film transistors (TFTs). However, the Ni residues degrade the device performance. In this study, a new method for manufacturing MIC-TFTs using drive-in Ni-induced crystallization with a chemical oxide layer (DICC) is proposed. Compared with that of MIC-TFTs, the on/off current ratio (I on /I off ) of DICCTFTs was increased by a factor of 9.7 from 9.21 9 10 4 to 8.94 9 10 5 . The leakage current (I off ) of DICC-TFTs was 4.06 pA/lm, which was much lower than that of the MIC-TFTs (19.20 pA/lm). DICC-TFTs also possess high immunity against hot-carrier stress and thereby exhibit good reliability.

Section: Introductionmentioning

confidence: 99%

Improved Electrical Performance and Reliability of Poly-Si TFTs Fabricated by Drive-In Nickel-Induced Crystallization with Chemical Oxide Layer

Lai

Chang

2011

“…However, NILC poly-Si grain boundaries trap Ni and NiSi 2 precipitates, which increase the leakage current and shift the threshold voltage. [4][5][6][7][8] To improve device performance, Ni contamination inside the NILC poly-Si film should be reduced. In previous work we used an amorphous silicon (a-Si) layer and an etch-stop layer to reduce Ni residues inside NILC poly-Si.…”

Section: Introductionmentioning

confidence: 99%

Using Phosphorus-Doped α-Si Gettering Layers to Improve NILC Poly-Si TFT Performance

Wang

2009

Ni-metal-induced lateral crystallization (NILC) has been utilized to fabricate polycrystalline silicon (poly-Si) thin-film transistors (TFTs). However, the current crystallization technology often leads to trapped Ni and NiSi 2 precipitates, thus degrading device performance. In this study, phosphorus-doped amorphous silicon (p-a-Si) and chemical oxide (chem-SiO 2 ) films were used as Ni-gettering layers. After a gettering process, the Ni impurity within the NILC poly-Si film and the leakage current were both reduced, while the on/off current ratio was increased. This gettering process is compatible with NILC TFT processes and suitable for large-area NILC poly-Si films.

“…Unfortunately, the NILC poly-Si grain boundaries trap Ni and NiSi 2 precipitates, which increase the leakage current and shift the threshold voltage. [2][3][4][5][6] Therefore, Ni contamination inside the NILC poly-Si film should be reduced. Several metal gettering methods have been employed to reduce the amount of undesired metallic impurities in Si.…”

Section: Introductionmentioning

confidence: 99%

Improved Gettering Efficiency of Ni from Nickel-Mediated Crystallization Silicon Using Phosphorus-Doped Amorphous Silicon

Wang

2009

Ni-metal-induced lateral crystallization (NILC) has been utilized to fabricate polycrystalline silicon thin-film transistors. However, the NILC process often leads to Ni and NiSi 2 precipitates being trapped. In this study, two kinds of films were used as gettering layers: (1) amorphous Si and (2) phosphorusdoped amorphous Si. After annealing at 550°C for 12 h, it was found that phosphorous dopant did improve the gettering efficiency of amorphous Si.