Gate bias stress induced instability of InGaZnO thin film transistor under different sputter power

IGZO film, as the active layer of thin film transistor, is prepared by different sputter power. The film morphology and the electrical characteristics of IGZO film are measured by scanning electron microscopy and Hall effect measurement system. The instability of IGZO TFT prepared by different sputter power under gate bias stress is studied. The result shows that, in a certain range, the film prepared by lower sputter power has rough surface, more defect density and lower carrier concentration. Positive gate bias induces IGZO-TFT positive voltage threshold shift, but negative gate bias stress do not produce voltage threshold shift.