Fabrication of a High-Performance Poly-Si Thin-Film Transistor Using a Poly-Si Film Prepared by Silicide-Enhanced Rapid Thermal Annealing Process

Abstract

A 50-nm thick polycrystalline Si film was fabricated by the crystallization of anamorphous Si film using silicide-enhanced rapid thermal annealing (SERTA). The amorphous Si film was deposited on a 5-nm thick polycrystalline Si seed layer containing nickel silicide precipitates in grain boundary areas. With the help of the silicide precipitates, the RTA temperature decreased from 730 to 680 degrees C and the grain size of the crystallized polycrystalline Si film increased to 1.4 - 2.2 mu m. Few defects were found within the grains and the Ni concentration in the polycrystalline film decreased to 1 x 10(18) cm(-3) due to the very-thin seed layer that contained nickel silicide precipitates. As a result, the field-effect hole mobility in the p-channel poly-Si thin film transistors (TFTs), fabricated employing the polycrystalline Si film, was as high as 169 cm(2)/V.s at a drain voltage of V-D = -0.1 V; the subthreshold swing was as small as 0.24 V/decade. The minimum leakage current at V-D = 5 V was 1.5 x 10(-10) A with very good diode characteristics.