Improving the Electrical Properties of NILC Poly-Si Films Using a Gettering Substrate

Abstract

Abstract-Ni-metal-induced lateral crystallization (NILC) of amorphous silicon (α-Si) has been employed to fabricate polycrystalline silicon (poly-Si) thin-film transistors. However, current crystallization technology often leads to Ni and NiSi 2 precipitates being trapped, thus degrading the performance of the device. We proposed using α-Si-coated wafers as Ni-gettering substrates. After bonding the gettering substrate with the NILC poly-Si film, both the Ni-metal impurity within the NILC poly-Si film and the leakage current were greatly reduced, thus increasing the ON/OFF current ratio.

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

“…17 This might be because, in this study, only a single 100-nm-thick p-a-Si film was used as the gettering layer, while in the study on gettering substrate, two a-Si films and a Si wafer were used as gettering layers. As a result, the gettering efficiency of gettering substrates was better than that of p-a-Si films.…”

“…16,17 Moreover, Ni residues promote thermionic-emission-dominated leakage current at higher V D . With the reduction of the Ni concentration, the leakage current was reduced and the negative shift of V TH was suppressed at high V D .…”

“…17 To form the GETR-Si film, the NILC-Si film was bonded to the Nigettering substrate and then annealed at 550°C for an additional 12 h. Following the gettering process, the Ni-gettering substrate was separated by using a razor blade. After the Ni-gettering process, it was also found that the number of silicide-etched holes at the NILC/NILC boundaries was greatly reduced, while the V TH of the GETR TFTs was increased.…”

Improved Uniformity and Electrical Performance of Continuous-Wave Laser-Crystallized TFTs Using Metal-Induced Laterally Crystallized Si Film

“…To form the a-Si film, a 100-nm-thick silane-based undoped a-Si layer was deposited using low-pressure chemical vapor deposition (LPCVD). To form the MILC-Si film, Ni lines were deposited on the a-Si film and subsequently annealed at 550°C for 12 h. 9 Both films were then irradiated using a CW laser at various output powers (2.5 W, 3.8 W, and 5 W). When fabricating the MILCLC poly-Si, the scanning direction of the CW laser was parallel to the MILC needle-like poly-Si grains.…”

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

“…They involve using a-Si/silicon-nitride films, a-Si-coated Si wafer, and contact holes covered with a-Si film. [12][13][14] During the gettering process, Ni atoms were diffused from the NILC film to the a-Si layer due to the concentration gradient. However, when the system reached equilibrium, no more Ni diffused into the gettering layer.…”