Determining the Thermal Generation Rate of Minority Charge Carriers at Semiconductor - Ultrathin Oxide Interfaces

摘要

A simple proximate method for determining the generation rate G_s of electron - hole pairs in metal-ultrathin oxide - semiconductor (MOS) structures is proposed. This method is based on measurements of dynamic current - voltage characteristics of MOS structures in the region of deep depletion of the semiconductor surface and on the comparison of these data to a quasi-equilibrium volt-farad characteristic (VFC) of an ideal MOS structure. This approach to determining G_S from the value of the structure capacitance is insensitive either to a shift of the VPC, which is caused by the presence of built-in charges, or a recharge of localized electron states in the oxide and at the Si-SiO_2 interface. The proposed technique also allows one to take the influence of a tunneling current through an insulator on the measurement results into account. The algorithm was tested in studies of generation and annihilation processes of centers of generation of electron - hole pairs in n-Si-based MOS structures with an ultrathin (≌4 nm) oxide.