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. D2 annealing was more effective in curing the interface damages than H2 annealing, and the strength to resist ac electrical stress was enhanced significantly after D2 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.