High performance LTPS TFT with very large grains produced by sequential lateral crystallization

Advanced Display Research Center and Department of Physics, Kyung Hee University, Dongdaemoon-ku, Seoul 130-701, Korea

Corresponding authors: sjpark@boehydis.com jjang@khu.ac.kr

Received: 12 May 2004
Revised: 15 June 2005
Accepted: 7 July 2005
Published online: 14 September 2005

Abstract

We report the structural and electrical properties of polycrystalline silicon on glass crystallized by using a CW Nd:YVO₄ laser. Various microstructures appear on amorphous silicon after a scanning of the laser regardless of the crystallization process parameters such as laser power and scan speed. The crystallized region could be characterized by their grain size as 3 distinct regions; RTA-SPC (rapid thermal annealed-solid phase crystallization) region, small-grain region and SLC (sequential lateral crystallization) region with very large grains of ~10 μm. To verify its electrical properties, p-ch TFTs were fabricated on the 3 different regions. The characteristics of TFTs on SLC region were superior to those on other regions and average performances of SLC poly-Si TFTs were  cm²/V s,  V, S.S. = 0.5 V/dec, and  pA/μm at  V, respectively.