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°C and the grain size of the crystallized polycrystalline Si film increased to 1.4 — 2.2 μm. Few defects were found within the grains and the Ni concentration in the polycrystalline film decreased to 1 × 10¹⁸ 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 cm²/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 = 5V was 1.5 × 10⁻¹⁰ A with very good diode characteristics.