Study on electrical degradation of p-type low-temperature polycrystalline silicon thin film transistors with C-V measurement analysis

Shih Che Huang*, Yu Han Kao, Ya-Hsiang Tai

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Laser recrystallized low-temperature poly-silicon (LTPS) films have attracted attention for their application in thin-film transistors (TFTs), which are widely used in active matrix display. However, the degradation behavior of p-type LTPS TFTs is not quite clarified yet. In this paper, the instability mechanisms of p-channel LTPS TFTs under DC bias stress have been investigated. From the IV transfer curves, it was observed that LTPS TFT's mobility increases after stress at some bias conditions. This degradation is most likely caused by interface traps between the poly-Si thin film and the gate insulator, as well as the damaged junction of the drain from stress. In this work, the assumption is examined via C-V measurement. It is found that the CGD curves of the stressed TFT slightly increase for the gate voltage smaller than the flat band voltage VFB. However, the CGS curves of the stressed device are almost the same as those before stress. By employing simulation, it is found that the degradation of p-type TFTs under this stress condition is mainly caused by the trapped charges at the interface between the gate and the drain region, which is generated by the high voltage difference applied during DC bias stress.

Original languageEnglish
Pages (from-to)1206-1209
Number of pages4
JournalThin Solid Films
Volume515
Issue number3
DOIs
StatePublished - 23 Nov 2006

Keywords

  • C-V (capacitance-voltage) measurement
  • LTPS
  • p-type
  • Poly-Si
  • Thin film transistor

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