Title :
The charge-pumping technique for grain boundary trap evaluation in polysilicon TFTs
Author :
Koyanagi, Mitsumasa ; Baba, Yoshihiro ; Hata, Kiyomi ; Wu, I-Wei ; Lewis, Alan G. ; Fuse, Mario ; Bruce, Richard
Author_Institution :
Hiroshima Univ., Kagamiyama, Higashi-Hiroshima, Japan
fDate :
3/1/1992 12:00:00 AM
Abstract :
Polysilicon thin-film transistor (poly-Si TFT) characteristics were evaluated by using the charge-pumping technique. The recombination current at the grain boundary traps is measured as the charge-pumping current in this technique. Therefore, the influence of the grain boundary traps is directly evaluated. It was confirmed that a large number of acceptorlike and donorlike traps exist at the grain boundaries in poly-Si TFTs. The trap density is derived from the pulse falltime dependence of the charge-pumping current. The influence of process temperature on trap properties is examined using the charge-pumping technique.<>
Keywords :
defect electron energy states; elemental semiconductors; grain boundaries; semiconductor device testing; silicon; thin film transistors; Si-SiO/sub 2/; acceptorlike traps; charge-pumping current; charge-pumping technique; donorlike traps; grain boundary trap evaluation; polysilicon TFTs; pulse falltime dependence; recombination current; Annealing; Charge pumps; Current measurement; Electron traps; Fuses; Grain boundaries; Implants; Plasma temperature; Thin film transistors; Threshold voltage;
Journal_Title :
Electron Device Letters, IEEE
