Positive bias temperature stress induced degradation in p-channel poly-Si thin-film transistors

Positive bias temperature stress induced degradation in p-channel poly-Si thin-film transistors (TFTs) was systematically investigated. Two-stage degradation behavior is observed. The first-stage degradation is related to electron trapping via Fowler-Nordheim (F-N) tunnelling and de-trapping through Poole-Frenkel (P-F) emission. While the second-stage degradation is attributed to hydrogen related positive charge creation in the gate oxide.