Chemical Vapour Deposition of Amorphous Silicon with Silanes for Thin Film Transistors –The Influence of the Amorphous Silicon Deposition Temperature–

Abstract

Amorphous silicon films have been prepared by low pressure chemical vapour deposition of monosilane, disilane and trisilane. The deposition temperatures ranged from 385°C to 555°C. The hydrogen content in the films was approximately 3 atomic percent and the optical band-gap was 1.6∼1.7 eV. Simple inverted staggered thin-film transistors were made with thermal silicon dioxide as the gate insulator. After annealing in a hydrogen radical rich ambient the field-effect mobilities for electrons were as high as 2.0 cm 2 /V·s and almost independent of temperature from 385°C to 500°C. At higher temperatures the mobility decreased rapidly and was less than 0.1 cm 2 /V·s at 555°C. These results appeared to be independent of the source gas.