The current status and future prospects of poly-Si devices

Over the past twenty years the use of thin-film transistors (TFTs) deposited onto glass substrates has developed into a new discipline, large-area microelectronics. This is now the subject of intensive industrial activity because of its applications, particularly the application to active-matrix addressing of LCDs. The transistors used in large-area microelectronics are insulated-gate FETs. Three thin-film semiconductors have received significant attention for use as the channel material, namely cadmium selenide, amorphous silicon, and polycrystalline silicon. It is becoming increasingly clear that polysilicon offers the best overall combination of properties. Salient points in this respect are: superior stability and lifetime; good performance at high ambient temperatures; no photo effect; CMOS compatibility; mobilities sufficient for useful circuitry; small, self-aligned, transistors; low parasitic capacitance; and use of intrastructure of silicon science and technology