Investigation of Degradation Behavior During Illuminated Negative Bias Temperature Stress in P-Channel Low-Temperature Polycrystalline Silicon Thin-Film Transistors

In this letter, a study of physical mechanisms is introduced to describe an abnormal phenomenon in transfer characteristics while p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) were subjected to a negative bias temperature stress (NBTS) in an illuminated environment...

Full description

Saved in:
Bibliographic Details
Published in:IEEE electron device letters 2021-05, Vol.42 (5), p.712-715
Main Authors: Wang, Yu-Xuan, Chang, Ting-Chang, Tai, Mao-Chou, Wu, Chia-Chuan, Tu, Yu-Fa, Chen, Jian-Jie, Huang, Wei-Chen, Shih, Yu-Shan, Chen, Yu-An, Huang, Jen-Wei, Sze, Simon
Format: Article
Language:English
Subjects:
Bias
Degradation
Edge effect
Electrical measurement
Electron recombination
illumination
Lighting
Low temperature
LTPS
negative bias temperature stress
Polycrystals
Polysilicon
Semiconductor devices
Silicon
Silicon films
Stress
Temperature measurement
TFT
Thin film transistors
Threshold voltage
Transistors
Ultraviolet radiation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this letter, a study of physical mechanisms is introduced to describe an abnormal phenomenon in transfer characteristics while p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) were subjected to a negative bias temperature stress (NBTS) in an illuminated environment. In general, under NBTS, the transfer characteristics exhibits a negative shift of threshold voltage and a degradation of subthreshold swing. Here, however, experimental results reveal that the degree of degradation is different after NBTS is applied to poly-silicon TFTs in a darkened and in an ultraviolet condition. This variation is mainly a result of the light-generated electrons recombining with the inversed holes, and leading to a lower degree of degradation. Moreover, we found that the influence of the UV light is an edge effect at different channel lengths. This letter investigates the illumination effect in LTPS TFTs during NBTS, and the phenomenon is clarified by electrical measurements and by trap state extraction.
ISSN:0741-3106
1558-0563
DOI:10.1109/LED.2021.3068423