Tensile Stress Effect on Performance of a-IGZO TFTs With Source/Drain Offsets

We report the effect of repeated tensile bending stress on the electrical performance of amorphousindium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with source/drain offset. The tensile strain induces the negative transfer shift for the conventional TFTs, but the ON-current (ION) increases significantly for the offset TFTs with negligible change in threshold voltage (VTH). The experimental results can be fitted well with technology computer aided design simulation by the generation of donor-like states in the bending region of the a-IGZO semiconductor. The degraded TFT performance can be completely recovered by thermal annealing at 250 °C for 1 h, confirming the generation of the donor-like metastable defects, oxygen vacancies.