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

Abstract

Distributions of the gate-dielectric EBG(x, y) and semiconductor-dielectric EBS(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 EBG(x, y) distribution has a characteristic dome-like shape which corresponds with the independently determined shape of the effective contact potential difference fMS(x, y) distribution. On the other hand, the EBS(x, y) distribution is of a random character. It is shown that the EBG(x, y) distribution determines the shape of the fMS(x, y) distribution. The model of the EBG and EBS barrier height distributions over the gate area has been proposed.

Keywords

• barrier height
• effective contact potential difference
• MOS system