Slow Trap Properties and Generation in Al2O3/GeOx/Ge MOS Interfaces Formed by Plasma Oxidation Process

Abstract

Understanding of slow traps near Ge MOS interfaces and reduction of the slow trap density are one of the most crucial issues for realizing Ge CMOS devices, in addition to the thin equivalent oxide thickness (EOT) and the low density of fast interface states (Dit). In this study, we examine the slow trap density and location in the Al2O3/GeOx/Ge interfaces fabricated by plasma oxidation. The slow trap density of Al2O3/GeOx/Ge MOS interfaces formed by pre-plasma oxidation (pre-PO) is compared with that of the MOS interfaces formed by post-plasma oxidation (post-PO). Also, the dependence of the slow trap density on the GeOx and Al2O3 thickness is systematically evaluated for the Al2O3/GeOx/Ge MOS interfaces formed by pre-PO. It is found that additional slow traps for electrons can be generated during the post-PO process near the conduction band side of Ge. It is also found that the main slow traps for electrons and holes in the Al2O3/GeOx/Ge MOS interfaces can locate near the GeOx/Ge interfaces and the Al2O3...