Properties of Patterned and CW Laser-Crystallized Silicon Films on Amorphous Substrates

Abstract

Semiconducting films on insulating substrates are of technological interest for electronic devices. In particular, a thin-film transistor technology which is compatible with bulk glass substrates would have immediate application in large-area arrays. It has recently been demonstrated that laser-crystallized silicon films can provide the semiconducting material for such a technology [1,2]. As deposited, a polycrystalline silicon film is composed of fine grains (nominally 50 nm in diameter) and is unsuitable as a semiconducting material for active devices due to the dominating effects of grain boundaries on the electrical properties. Laser crystallization is used to increase the grain size to dimensions that are comparable to or greater than those of the device structure, thereby minimizing the detrimental effects of grain boundaries on device operation. It has been shown that heat flow and crystallization during laser irradiation can be controlled to obtain large grains on amorphous substrates [3]. A key advantage of using silicon thin films is the application of conventional silicon microelectronic processing technologies for the fabrication of thin-film devices and circuits.