<title>Polycrystalline silicon thin film transistor technology for flexible large-area electronics</title>

Abstract

The burgeoning number of mobile consumer electronics has created a demand for lightweight, low-cost, portable displays. The development of a polycrystalline-silicon thin film transistor (TFT) technology compatible with plastic substrates will enable displays and large-area electronics that are low power, rugged and flexible. Significant challenges exist in the development of a polysilicon TFT fabrication process that is compatible with plastic substrates, since plastic has a much lower thermal budget than glass substrates. In general, superior polysilicon TFT performance is achieved with higher temperature fabrication processes because the quality of the polysilicon and gate- dielectric films are very sensitive to process temperature. In this work, an ultra-low-temperature process for fabricating high-quality self-aligned polysilicon TFTs on flexible plastic substrates is described. All fabrication steps are performed at or below 100 degrees C. Polysilicon is formed by crystallizing sputtered amorphous Si films using a XeCl excimer laser with a pulse duration of approximately 35 ns. Gate oxide deposition is formed using high-density plasma CVD, and metal films are deposited by sputtering.