Characterization of low temperature polysilicon TFTs with self-aligned graded LDD structure

Ching Wei Lin*, Li Jing Cheng, Yin Ng Lu, Huang-Chung Cheng

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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.

Original languageEnglish
Title of host publicationAdvanced Materials and Devices for Large-Area Electronics
Pages329-334
Number of pages6
DOIs
StatePublished - 1 Dec 2001
Event2001 MRS Spring Meeting - San Francisco, CA, United States
Duration: 16 Apr 200120 Apr 2001

Publication series

NameMaterials Research Society Symposium Proceedings
Volume685
ISSN (Print)0272-9172

Conference

Conference2001 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period16/04/0120/04/01

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  • Cite this

    Lin, C. W., Cheng, L. J., Lu, Y. N., & Cheng, H-C. (2001). Characterization of low temperature polysilicon TFTs with self-aligned graded LDD structure. In Advanced Materials and Devices for Large-Area Electronics (pp. 329-334). (Materials Research Society Symposium Proceedings; Vol. 685). https://doi.org/10.1557/PROC-685-D12.7.1