Aligned Polycrystalline Silicon Array Thin Film by XeCl Excimer Laser Annealing for AMOLED Displays

Abstract:

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Low temperature polycrystalline silicon (LTPS) thin film transistors (TFTs) are demanded to fabricate high performance liquid crystal displays (LCD) and organic light-emitting diode displays (OLED). The mobility of poly-Si TFT can be two orders of magnitude higher than that of amorphous Si (a-Si) TFT. Excimer laser annealing has been studied to be the most promising technology to meet the stringent requirement in high speed operation. The process parameters were identified as a-Si thickness, laser energy density, overlap ratio, annealing atmosphere and pre-clean condition. The a-Si layer of 40-50 nm was deposited by plasma enhanced chemical vapor deposition (PECVD). The XeCl excimer laser was irradiated on the a-Si film at room temperature under N2 or N2/O2 environment. The energy density ranged 250-400 mJ/cm2, and the overlap ratio was 95-99%. The highly aligned poly-Si array thin film could be obtained. The grain size has been about 0.31x0.33 μm2, and the regular arrangement in poly-Si grains was discussed. In addition, the PMOS TFT has been fabricated from the aligned poly-Si array. The mobility was as high as 100 cm2/Vs and the sub-threshold swing was around 0.24 V/dec. The threshold voltage was -1.25 V and the on/off current ratio was about 106.

Info:

Periodical:

Solid State Phenomena (Volumes 124-126)

Edited by:

Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park

Pages:

371-374

DOI:

10.4028/www.scientific.net/SSP.124-126.371

Citation:

C.N. Chen et al., "Aligned Polycrystalline Silicon Array Thin Film by XeCl Excimer Laser Annealing for AMOLED Displays", Solid State Phenomena, Vols. 124-126, pp. 371-374, 2007

Online since:

June 2007

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Price:

$35.00

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