Location- and orientation- controlled crystallization of amorphous silicon thin films through contact-printing with Ni tape

Abstract

Polycrystalline silicon (poly-Si) TFTs have attracted particular attention due to the fact that the poly Si TFTs have better characteristics than amorphous silicon thin-film transistors, including higher carrier mobility and good operation stability. Among the many different methods for producing poly-Si films, silicide mediated crystallization (SMC) of amorphous silicon have been investigated extensively for the advantage of producing large-grained poly-Si films at low temperatures which are compatible for glass substrates while maintaining a high throughput without the need for expensive machinery. However, for further applications of poly Si, the location and orientation of grains need to be controlled as well as the grain size. These issues become more critical as grains become larger, since there are fewer grains within a channel. Since the nucleation is a stochastic process, control of the grain orientation in poly-Si is difficult. However, if an external template for crystallization is provided, both the orientation and location of crystal grains can be controlled. In this study, we report on the results of location- and orientation- controlled crystallization of a-Si:H thin films through two kinds of contact-printing crystallization methods using single crystalline Ni tapes as nucleation template.