MIT Department of Electrical Engineering & Computer Science

Massachusetts Institute of Technology

MTL VLSI SEMINAR

Tuesday
September 20, 1994
3:30 Reception
4:00 Lecture

Room 34-101
50 Vassar Street

High Performance TFTs by Solid Phase Crystallization (SPC) and Excimer Laser Annealing (ELA)

Dr. Takashi Noguchi
Sony Corporation
MIT MTL Visitor

Very active research on Thin Film Transistors (TFTs) is being carried out not only for LCDs, but also for SRAMs. TFTs with large grained polysilicon are required in order to obtain high mobility, while smaller grain sizes are considered to be suitable in uniformity.

The behavior of Solid Phase Crystallization (SPC) on amorphous silicon has been studied, and TFTs have been fabricated on films which exhibit large grain sizes and their characteristics were investigated. Excimer Laser Annealing (ELA) has been introduced in efforts to reduce the temperature for TFT processing, and studies of films with small and large grains which have undergone ELA have improved performance.

The variation of device parameters with channel dimensions has been investigated. Short channel TFTs indicate some problems with uniformity of the device characteristics, however these characteristics approach those of high performance devices such as SOI. This talk will focus on the problems associated with the manufacture TFTs and the effect of various annealing approaches for improving their characteristics.