The Built-in Voltage and the Charge Distributions in the Oxide of MOS Structure

The built-in voltage which exists in an oxide layer of a MOS structure was determined by analyzing the time saturated N F B value as a function of voltage of the B.T. treatment. This voltage V M S was assured by observing the transient ion current waveform through the MOS structure. The physically meaningful quantities of φ M -χ, the built-in voltage in the SiO 2 and the fixed positive charge at the Si-SiO 2 interface were derived for various samples. The potential, the field, and the charge distribution in the SiO 2 were calculated by using solutions of the Poisson-Boltzmann equation by which the fundamental characteristics of the bias voltage dependence of the saturated N F B in the B.T. treatment was found to be well understood.