Hot Carrier Effects in Self-aligned and Offset-Gated Polysilicon Thin-Film Transistors

摘要

The effects of hot carriers on the transfer characteristics of self-aligned and offset-gated polysilicon thin-film transistors (TFTs), with channel length L = 10 μm and offset length ΔL = 2 μm, are investigated. In the self-aligned device, the on-state current is substantially reduced, whereas the subthreshold slope remains almost unaffected. In the offset gated device, the transfer characteristic is shifted first positively and then negatively, the on-state current is still substantially reduced and well-defined kinks are formed in the subthreshold region. The device degradation is found to become more pronounced in the offset gated device. A model explaining the post-stress performance of the offset-gated device is presented.