Characteristics of PBTI and hot carrier stress for LTPS-TFT with high-κ gate dielectric

In this letter, the characteristics of positive bias temperature instability (PBTI) and hot carrier stress (HCS) for the low-temperature poly-Si thin-film transistors (LTPS-TFTs) with HfO ₂ gate dielectric are well investigated for the first time. Under room temperature stress condition, the PBTI shows a more serious degradation than does HCS, indicating that the gate bias stress would dominate the hot carrier degradation behavior for HfO ₂ LTPS-TFT. In addition, an abnormal behavior of the I _min degradation with different drain bias stress under high-temperature stress condition is also observed and identified in this letter. The degradation of device's performance under high-temperature stress condition can be attributed to the damages of both the HfO ₂ gate dielectric and the poly-Si grain boundaries.