Patent ID: 6329270
Filing Date: 2001-12-11
Classification: G02F,H01L,Y02E,Y02P

Abstract:
In forming thin film transistors in polycrystalline film formed from substantially amorphous matter on a transparent liquid crystal display (""LCD"") substrate, a method comprising the steps of:providing a transparent LCD substrate having a surface for receiving the deposition of semiconductor matter thereon, said substrate surface being flat; andforming a film of polycrystalline semiconductor matter on said flat surface of said LCD substrate, said step of forming a film of polycrystalline semiconductor matter including:a) depositing amorphous matter on the transparent LCD substrate with a PECVD process using a SiH.sub.4 and H.sub.2 gas mixture at a power level of approximately 0.16783 W per cm.sup.2, at a temperature of approximately 320.degree. C., a total pressure of approximately 1.2 Torr, and a flow rate of SiH.sub.4 to H.sub.2 of approximately 100:1;b) depositing the amorphous matter in Step a) at a deposition rate of less than 10 .ANG./s and a deposition temperature of approximately 380 degrees C., whereby microcrystallites are produced during the deposition step within the amorphous matter to form a microcrystallite film;c) depositing the microcrystallite film of Step b) to an overall thickness of less than approximately 500 .ANG.;d) heating the film deposited in Step c) with an ELC process using a wavelength of approximately 308 nm, or less, to selectively melt microcrystallites such that at least some microcrystallites remain to provide seed crystals for subsequent crystallization of the post-melt melted area to form crystal grains in the film; ande) forming a polycrystalline film having an electron mobility of greater than 150 cm.sup.2 /Vs.