Affiliation:
1. School of Electronic and Computer Engineering Peking University Shenzhen China
2. Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong China
3. School of Integrated Circuits Peking University Beijing China
Abstract
The influence of H2O on self‐aligned top‐gate (SATG) a‐ InGaZnO thin‐film transistor (TFT) was systematically investigated by performing the high‐temperature high‐humidity (HTHH) test (50 °C, 80% RH). Though initial electrical characteristics were well maintained, the stability under positive bias stress (PBS) was considerably deteriorated, including an abnormal negative Vth shift, degraded SS, and increased off current. The mechanism of H2O‐induced instability was proposed to be the dissociation of H2O molecules and the migration of hydrogen (H) atoms into the a‐IGZO channel. The hydrogen diffusion and doping effects in SATG a‐IGZO TFTs were further proved by SiNx‐passivated TFTs with regulated H content in SiNx layers.