Hexagonal a-Si:H TFTs, a New Advanced Technology for Flat Panel Displays
Hojin Lee, Juhn S. Yoo, and Jerzy Kanicki
In this project, inverted stagger Hexagonal hydrogenated amorphous silicon thin-film transistors (HEX a-Si:H TFTs) were invented and fabricated with a 5-photomask process used in the processing of the active-matrix liquid crystal displays. We show that the output current of Hexagonal a-Si:H TFT connected in parallel increases linearly with their number within a given pixel circuit. Current-voltage measurements indicate that a high ON-OFF current ratio and a low sub-threshold slope can be maintained for multiple Hexagonal TFTs connected in parallel while the field-effect mobility and threshold voltage remain identical to a single HEX a-Si:H TFT. Due to a unique device geometry, an enhanced electrical stability and a larger pixel aperture ratio can be achieved in the multiple a-Si:H HEX-TFT in comparison to standard single a-Si:H TFT having same channel width. These HEX-TFT electrical characteristics are very desirable for future active-matrix organic light-emitting displays. This project is supported by RND Center of LG Philips LCD, Korea.
H. Lee, J.S. Yoo, C.-D. Kim, I.B. Kang and J. Kanicki, IEEE Trans. Electron Devices, 329-336, 2008.
enhanced electrical stability and a larger pixel aperture ratio can be achieved in the multiple a-Si:H HEX-TFT in comparison to standard single a-Si:H TFT having same channel width. These HEX-TFT electrical characteristics are very desirable for future active-matrix organic light-emitting displays. This project is supported by RND Center of LG Philips LCD, Korea.