ABSTRACT
In the previous chapter we looked at the device physics of thin film transistors (TFTs) and briefly studied the threshold voltage shift (VT shift) in the TFTs. The physics behind the threshold voltage shift involved the mechanisms of defect creation and trapping at the semiconductor insulator interface. The mechanism of defect creation involved the conversion of weak bonds into dangling bonds. This mechanism occurs with different activation energies and therefore the threshold voltage shift in non-crystalline semiconductor based TFTs was shown to have a stretched exponential behavior with time.
