Patent ID: 6015720
Filing Date: 2000-01-18
Classification: G02F,H01L

Abstract:
A method of making a thin film semiconductor device, comprising the steps of:providing an insulating substrate comprising a glass material having a maximum processing temperature of a 600.degree. C. having a surface;growing a precursory polycrystalline semiconductor layer substantially free of hydrogen and comprising clusters of microscopic polycrystalline silicon crystal grains having a grain diameter of greater than 3 nm on the surface by low pressure or atmospheric pressure chemical vapor deposition at a temperature of from about 500 to 600.degree. C. using 100% SiH.sub.4 as a gaseous raw material;implanting impurities into device regions of the precursory polycrystalline semiconductor layer to form source and drain regions in each said device regions;forming an anti-reflective film on the implanted precursory polycrystalline semiconductor layer at a temperature below the maximum processing temperature of the insulating substrate;irradiating the precursory polycrystalline semiconductor layer in a single shot with an excimer pulse laser having a rectangular shaped beam having a cross-sectional intensity distribution such that beam intensity in peripheral regions of the beam is higher than beam intensity in a central region of the beam by about 1 to about 70% and having an energy density of from about 150 to about 500 mJ/cm.sup.2 and a pulse duration time of from about 10 to about 1000 nanoseconds such that a substrate temperature of from about 20 to about 450.degree. C. is maintained to recrystallize the precursory layer to provide a polycrystalline semiconductor thin film having a crystal grain size of great than or equal to about 467 nm and to activate implanted impurities;removing the anti-reflective film;forming a gate insulating film in each device region in a channel region defined between source and drain regions; andthereafter, forming an aluminum gate electrode on the gate insulating film to provide said thin film semiconductor device.