Prospective crystallization of amorphous Si films for new Si TFTs

Abstract

AbstractProspective crystallization results of amorphous silicon film are reviewed and are discussed. Silicon TFTs are playing an important role for Active‐Matrix Flat Panel Displays (AM‐FPD) based on amorphous or poly‐Si thin‐film transistors (TFTs). Poly‐Si TFTs provide a possibility to develop highly functional system on pane (SoP) applications. In order to get a high performance TFT, large poly‐crystal grains or high cystallinity for the film is required. Two basic crystallization techniques namely solid phase crystallization (SPC) and excimer laser crystallization (ELC) are reviewed and relating issues are described. A grain growth technique has been developed based on the two crystallization techniques, so far. In order to mount a poly‐Si TFT system on a flexible panel such as a plastic, an excimer laser of UV pulse beam has an advantage for the TFT channel as well as for the source and drain contacts as a ultra‐low temperature poly‐Si (U‐LTPS) process. To realize a high performance TFT of uniform and high carrier mobility, location control crystallization had been proposed. Some of the distinctive results for crystal orientation control of (100) and (111) face using the laser crystallization techniques are described. In the future, single‐crystalline Si TFT of a functional 3D structure is expected to realize an advanced SoP for ubiquitous electronics era. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)