Positron Annihilation Study on Defects in HfSiON Films Deposited by Electron-Beam Evaporation

摘要

Vacancy-type defects in HfSiON high-k films were studied by the S-parameter of positron annihilation. In the as-deposited HfSiON films, high-density oxygen vacancies (Vos) induced a large built-in electric field (E_(built-in)) toward Si substrate. It was observed that the thermal positrons diffused from HfSiON films to Si substrate by the 'driving of the E_(built-in) Because HfSiON has a small characteristic S-parameter and Si substrate has a large characteristic S-parameter, the observed S-parameter was indirectly increased by the Vos. When most of Vos were compensated by annealing of the samples in nitrogen or oxygen ambient, the E_(built-in) reduced not to effectively drive thermal positrons from HfSiON to Si. Then the S-parameter was observed to be smaller.