Title :
Schottky-contact gated-four-probe a-Si:H TFT structure: a new structure to investigate the electrical instability of a-Si:H TFT
Author :
Chiang, Chun-Sung ; Chen, Chun-ying ; Kanicki, Jerzy
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
Abstract :
In this letter, we describe a new device structure, the Schottky-contact (SC) gated-four-probe (GFP) hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) structure, that can be used to study the electrical instability of a-Si:H TFTs induced by bias-temperature-stress (BTS). In this SC-GFP TFT structure, the evolution of both electron and hole conduction characteristics can he studied before and after BTS without the influence of source-drain contacts. We observed that low-bias negative stress induces a reduction in the deep-gap state density, while high-bias negative stress mainly causes trapping of holes in the gate-insulator. On the other hand, positive BTS induces mainly the trapping of electrons in the gate-insulator, which causes positive shifts of both electron and hole conduction characteristics.
Keywords :
Schottky barriers; amorphous semiconductors; elemental semiconductors; hydrogen; silicon; thin film transistors; Schottky-contact gated-four-probe a-Si:H TFT; Si:H; bias temperature stress; deep gap state density; electrical instability; electron conduction; electron trapping; gate insulator; hole conduction; hole trapping; hydrogenated amorphous silicon; thin film transistor; Amorphous silicon; Charge carrier processes; Computer displays; Contacts; Electrodes; Electron traps; Fabrication; Photonic band gap; Stress; Thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
