Progress in determination method for ultrathin Si-based oxide bandgaps from analysis of energy loss signals for photoelectrons

The energy bandgap (E_g) values of various dielectric oxides and nitrides have often been determined from the energy loss signals of the photoelectrons excited from O 1s and N 1s core levels. However, overlapping with other core line signals, if any, makes it difficult to determine the E_g value accurately. In this work, we have demonstrated that the analysis of energy loss signals of cation core lines instead of O 1s photoelectrons leads to an accurate determination of E_g values. The energy loss signals of Si 2p_3/2 photoelectrons for SiO₂ and HfSiO_xN_y are very suitable for avoiding the overlapping with other core level lines and to define the background levels and the zero-loss energy position. (author)