Location-control of large grains by μ-Czochralski (grain filter) process and its application to single-crystalline silicon thin-film transistors

This paper reviews an advanced excimer-laser crystallization technique, developed by our group, enabling location-control of the individual Si grains with a great precision. Combined microstructure and time-resolved optical reflectivity investigations during conventional excimer-laser crystallization will precede this to summarize phase transformation phenomena during the crystallization process. The location-control method uses photolithographically made local structural modification in the underlying materials (substrate). With the developed mu-Czochralski (grain-filter) process, large grains having a diameter of 6 mum can be set precisely at predetermined positions. We will also discuss the performance of the single-crystalline Si TFTs that are formed within the location-controlled Si grains. The field-effect mobility for electrons is 430 cm(2)/Vs on average, which is well comparable to that of TFTs made with silicon-on-insulator (SOI) wafers.