Hostname: page-component-7c8c6479df-995ml Total loading time: 0 Render date: 2024-03-29T07:06:42.282Z Has data issue: false hasContentIssue false

Characterization of Low Temperature Polysilicon TFTs with Self-Aligned Graded LDD Structure

Published online by Cambridge University Press:  17 March 2011

Ching-Wei Lin
Affiliation:
Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan, R.O.C.
Li-Jing Cheng
Affiliation:
Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan, R.O.C.
Yin-Lung Lu
Affiliation:
Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan, R.O.C.
Huang-Chung Cheng
Affiliation:
Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan, R.O.C.
Get access

Abstract

A simple process sequence for fabrication of low temperature polysilicon (LTPS) TFTs with self-aligned graded LDD structure was demonstrated. The graded LDD structure was self-aligned by side-etch of Al under the photo-resist followed by excimer laser irradiation for dopant activation and laterally diffusion. The graded LDD polysilicon TFTs were suitable for high-speed operation and active matrix switches applications because they possessed low-leakage-current characteristic without sacrificing driving capability significantly and increasing overlap capacitance. The leakage current of graded LDD polysilicon TFTs at Vd = 5V and Vg = −10V could attain to below 1pA/μm without any hygrogenation process, when proper LDD length and laser activation process were applied. The on/off current ratios of these devices were also above 108. Furthermore, due to graded dopant distribution in LDD regions, the drain electric field could be reduced further, and as a result, graded LDD polysilicon TFTs provided high reliability for high voltage operation.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Sameshima, T., Hara, M. and Usui, S. Jpn. J. Appl. Phys., 28 (1989) L2132 Google Scholar
2. Matsueda, Y., the proceeding of IDW '00 pp.171 Google Scholar
3. Park, C. M. et al. , IEEE Electron Device Lett., 18 (1997) pp.16 Google Scholar
4. Tanaka, K., Arai, H., and Kohda, S., IEEE Electron Device Lett., 9 (1988) pp.23 Google Scholar
5. Weiner, K. H., Carey, P. G., and McCarthy, A. M., Microelectronic Engineering, 20 (1993) pp.107 Google Scholar