Accurate evaluation of Ge metal-insulator-semiconductor interface properties

作者：Taoka Noriyuki^*; Ikeda Keiji; Mizubayashi Wataru; Morita Yukinori; Migita Shinji; Ota Hiroyuki; Takagi Shinichi

来源：Journal of Applied Physics, 2011, 110(6): 064506.

DOI：10.1063/1.3633517

To accurately evaluate the Ge metal-insulator-semiconductor (MIS) interface trap density (D-it) by employing the conventional method for Si MIS capacitors on Ge MIS capacitors, we have investigated the impact of majority and minority carrier responses on C-V curves and/or the energy distributions of D-it. It is found that the high-frequency C-V curve, which does not include the majority carrier response with interface traps, cannot be obtained near room temperature (RT) even at 1 MHz. Therefore, to accurately evaluate the D-it values using the Terman method, the C-V curve has to be measured at an appropriate temperature. Furthermore, in the conductance method, evaluations by the model including the narrow bandgap effects are needed to obtain accurate D-it of the Ge MIS interface near RT. Through such accurate evaluation, the interface properties with different kinds of interfacial layers have been investigated. Although the GeO2/Ge interface has a low D-it and a fixed oxide charge density, the total charged center density contributing to surface potential fluctuation is larger than those for the GeOx/Ge and GeOxNy/Ge interfaces. These results suggest that the evaluation methods of the Ge MIS interface taking into account the appropriate carrier responses is quite important to obtain accurate Ge MIS interface properties.

• 出版日期2011-9-15