Investigation of barrier height distributions over the gate area of Al-SiO2-Si structures

Abstract

Distributions of the gate-dielectric E_BG(x, y) and semiconductor-dielectric E_BS(x, y) barrier height values have been determined using the photoelectric measurement method. Modified Powell-Berglund method was used to measure barrier height values. Modification of this method consisted in using a focused UV light beam of a small diameter d =0.3 mm. It was found that the E_BG(x, y) distribution has a characteristic dome-like shape which corresponds with the independently determined shape of the effective contact potential difference f_MS(x, y) distribution. On the other hand, the E_BS(x, y) distribution is of a random character. It is shown that the E_BG(x, y) distribution determines the shape of the f_MS(x, y) distribution. The model of the E_BG and E_BS barrier height distributions over the gate area has been proposed.