Study on the Oxygen Partial Pressure Dependent Annealing Effect for SiO2/SiC Stack

Abstract

AbstractPost‐oxidation annealing in oxygen (O2) ambient can improve the quality of the SiO2/SiC stack without introducing foreign atoms. In order to reveal the annealing mechanism at different oxygen partial pressures (P(O2)), this work focuses on the dependence of the annealing effect on P(O2) in a wide range from 0.01 Pa to 101 kPa for SiO2/SiC stack. In order to minimize the C‐related defects generated during SiC oxidation, the SiO2/SiC stacks are formed by oxidizing the deposited Si on the SiC epitaxial layer. The electrical characteristics of the annealed samples show that low P(O2) is beneficial to improve the interface quality, and high P(O2) is beneficial to improve the oxide layer quality. In addition, time of flight secondary ion mass spectrometry and X‐ray photoelectron spectroscopy analysis shows that the distribution and filling of oxygen vacancies (V[O]) are consistent with the electrical results. Finally, a model describing V[O] filling amount with P(O2) is proposed to quantitatively characterize the dependence of the annealing effect on P(O2), which shows that the filling amount of V[O] is proportional to P(O2)n (n∼0.065). This model provides theoretical support for improving the quality of SiC MOS by O2 annealing.