Location-controlled crystallization of Si films for TFT circuitapplications

Large-area microelectronic applications require high-performance thin-film transistors for driver circuits. This is especially true in the case of "system-on-panel" applications where high levels of circuit integration are required to drive displays and sensors that are built onto the panel. While there are many methods that might be employed to crystallize Si films on lost-cost, high-temperature-intolerant substrates, very few offer the high performance characteristics that the applications demand. In this paper, we show that directionally solidified Si films can be readily used to fabricate high performance electronic devices for circuit applications. By only crystallizing those regions of the Si films that are used in the actual fabrication of TFTs, we show that many of the issues concerning low throughput rates can be avoided. Results from a CMOS ring oscillator showcasing the speed capability of such active layers are also presented.