An improved high frequency C-V method for interface state analysis on MIS structures

A technique to determine the surface band bending Psi(s) and the density of interface traps D-it, from modified bias-temperature-stress (BTS) and capacitance-voltage (C-V-g) measurements is proposed. The basic idea of this method is the use of a C-V-g curve recorded with traps frozen in the filled state to determine the semiconductor capacitance as a function of the surface potential C-sc(Psi(s)) and consequently Psi(s)(V-g) and D-it. The procedure eliminates the need for a theoretical calculation of the semiconductor capacitance C-sc and for knowledge of the doping profile. In addition it is not dependent on the motion of charges in the dielectric which are frozen at low temperature. Measurements are made on n-InP MIS structures and the results are compared to deep level transient spectroscopy measurements on the same samples. (C) 1997 Elsevier Science Ltd.