Fabrication of a Single Crystal Silicon Substrate for AM-LCD Using Vertical Etching of (110) Silicon

Abstract

In this paper, feasibility of crystalline silicon (c-Si) substrate for transmissive active matrix liquid crystal displays (AM-LCDs) has been investigated. The transparent pixel areas of AM-LCD were formed by vertical etching of (110) silicon substrate using anisotropie etching property of aqueous KOH. Combining this vertical etching process with the conventional MOSFET fabrication process, the pixel switching devices, peripheral circuits and transparent apertures were successfully integrated on the same c-Si substrate. The pixel NMOS devices exhibit an electron mobility of about 600cm²/V-s, a subthreshold slope of 65mV/decade and ON/OFF current ratio of 9 decades at 5V drain voltage. And the gate delay time is 3.3ns at 10V power voltage, measured from a ring oscillator which has enhancement-load type NMOS inverters having the (W/L) i_load- (W/L) _driverer of 25μm/15μm - 50μm/10μm.