Correlation of the VT drift in a-Si:H TFT to the optically observed flicker increase in AMLCD

The observed development of flicker with time in AMLCD panels has been correlated to the threshold voltage shift of the thin film transistors (TFTs) used in the panels. The effect of threshold voltage shift on panel flicker was calculated using a flicker model developed here. One set of AMLCD panels used for the flicker characterization employed top gate TFTs while a second set employed bottom gate TFTs. Optical measurements to determine the flicker voltage as a function of aging were performed on both types of panels. Electrical characterization of the TFTs extracted the threshold voltage from the C-V measurement. Samples of the TFTs were available on kerf strips for both panel types, and ensured that the optically characterized panels and the TFTs electrically characterized were manufactured in the same batch for each of the two panel types.