High current stress effects in amorphous-InGaZnO_4 thin-film transistors

摘要

Amorphous-InGaZnO_4 (a-IGZO) thin-film transistors (TFTs) on glass undergo large positive threshold voltage shifts (△V_(TH)) under high current stress (HCS)-a consequence of Joule heating of the active-layer. Here, we show that when the active layer is split into smaller parts, HCS induces negligible △V_(TH). When the active layer heats up during HCS, conducting electrons in the channel gain enough energy to surmount the energy barrier at the active-layer/gate-insulator interface and become trapped into deep states inside the gate-insulator. Splitting the active-layer into smaller parts increases the surface area for heat dissipation, resulting in the elimination of these self-heating effects.