Anomalous Off-Current Mechanisms in Poly-SI Thin Film Transistors

The anomalous off current (I
off
) in poly-Si thin film transistors (TFTs) is one of the major problems preventing the use of these devices in active matrix liquid crystal displays. While previous investigations have focused on the temperature range above 300K, in this study we analyse the behaviour of I
off
over a wider range of temperatures, namely 180 to 400 K. Our results provide for the first time evidence of a direct tunnelling mechanism for I
off
and allow the determination of the constant in the exponential term