Performance Improvement of Low-Temperature Polycrystalline Silicon Thin-Film Transistors with Fluorinated Silicate Glass Drive-In Masking Layer

Abstract

This study investigated a low-temperature polycrystalline silicon thin-film transistor (LTPS TFT) with a fluorinated silicate glass (FSG) drive-in masking layer on the channel layer to improve the device's performance. The FSG layer can also be patterned as a masking layer to define the source and drain (S/D) regions, and the activation of S/D regions and fluorine passivation treatment can be accomplished simultaneously. Fluorine atoms can diffuse from the FSG drive-in masking layer into the bulk channel to passivate the trap states, resulting in a considerable improvement of the electrical characteristics of the device. This demonstrated that the field-effect mobility increased from 10.9 to 30.4 cm2 V-1 s-1, and the on/off current ratio increased from 8.9 ×104 to 10.4 ×105. The proposed scheme is simple, economical, and suitable for mass production of large-sized displays.