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 lowtemperature poly-Si thin-film transistors (LTPS-TFTs) with HfO2 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 HfO2 LTPSTFT. In addition, an abnormal behavior of the Imin 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 HfO2 gate dielectric and the poly-Si grain boundaries.