[18a-E304-1~9] 13.4 Si processing /Si based thin film / MEMS / Equipment technology

△ [18a-E304-3] Surface Flattening of LTPS Thin Films by Laser Annealing and Electrical Properties of the LTPS-TFTs

〇(M1)Fuminobu Hamano¹, Kaname Imokawa^1,2, Daisuke Nakamura¹, Tetsuya Goto³, Hiroshi Ikenoue^1,2 (1.Kyushu Univ., 2.Dept. of Gigaphoton, Kyushu Univ., 3.Tohoku Univ.)

Keywords:Laser Annealing, Poly-Si, TFT

Thin film transistors (TFTs) are used as switching devices in flat panel displays. Low temperature poly-Si (LTPS) thin films are widely used as a channel material of the TFTs. Conventionally, the LTPS thin films are formed by an excimer laser annealing (ELA). It is well known that prominent ridges are formed on the LTPS thin films after ELA due to volume expansion by crystallization, and gate leakage current of the TFTs is induced by formation of the prominent ridges. It is one of the most serious issue of TFT fabrication. We thought that additional irradiation with an excimer laser could reduce and flatten the height of the prominent ridges, and thus improvement of yield of the TFT can be achieved.
In this presentation, we report on the reduction in height of the prominent ridges due to additional laser irradiation and changes of electrical properties of the LTPS-TFTs.