Effects of hydrogen and deuterium annealing on plasma process induced damages

Abstract

For n-channel metal-oxide semiconductor field effect transistor(MOSFET) devices with thin gate oxide, the effects of low temperature hydrogen and deuterium annealing on plasma process-induced damages are examined. The test devices were first exposed to the plasma during poly-Si gate or metal processes, and then the device characteristics were measured with the charge pumping method. It was observed that the metal process induced more interface traps than the poly-Si gate process. D-2 annealing was more effective in curing the interface damages than H-2 annealing, and the strength to resist ac electrical stress was enhanced significantly after D-2 annealing. The stability of interface properties was increased with the annealing temperature and time. It is concluded that the latent damages, which appear after electrical stress, originate from the plasma. process-induced damages that were unintentionally passivated by hydrogen atoms during subsequent processes.