P‐7.1: Effect of S/D Decap Times on Ion attenuation in ADS Pro TFT

Abstract

The thin film transistors (TFTs) based on hydrogenated amorphous silicon (a‐Si:H) often show a significant deterioration of electrical properties after ITO and source/drain (S/D) Decaping, it is necessary and valuable to clarify the cause and to solve the Ion drop problem induced by Decap. In this work, a‐Si:H TFT with Mo/Al/Mo three‐layers S/D electrode structure was fabricated and the device were undergone 0‐3 times Decap. The effect of S/D electrode Decap times on the electrical properties and content depth distribution of O, Si and Mo elements in samples were investigated. It is found the carrier concentration, mobility and Ion/Ioff decrease, but the resistivity increases with the increase of S/D Decap times. The invasion of impurity ions is the key factor causing the device's performance degradation. On the one hand, oxygen intrusion may lead to the formation of SiOX. On the other hand, the intrusion of Mo may bring about n‐type doping to Si, inducing a decrease in the carrier concentration of P‐doped a‐Si. Both will give rise to a larger resistance in the conductive path, resulting in a worse electrical performance.