Hydrogen Instability Induced by Postannealing on Poly-Si TFTs

This brief investigates hydrogen instability induced by postannealing. Results show that using a SiN capping layer can prevent the release of hydrogen from a polycrystalline-silicon channel. However, removing this SiN capping layer allows the hydrogen release during postannealing, and the resulting device performance becomes comparable to that of the control sample. Hydrogen release reduces the immunity of PBTI and NBTI. Two possible mechanisms can explain the increased preexisting defects associated with hydrogen release, which affects the NBTI and PBTI.