Distributions of barrier heights, difference of effective contact potential, and local values of flat-band voltage in Al–SiO2–Si and poly–Si–SiO2–Si structures

It was previously shown that the effective contact potential difference (φMS) in Al–SiO2–Si metal-oxide-semiconductor structures has a “dome-like” shape of distribution over the Al-gate area. In this paper we show that this shape is due to the distribution of the barrier height at the Al–SiO2 interface and that the characteristic shape of φMS(x,y) distribution is reflected in a similar shape of the flat-band voltage VFB(x,y)distribution over the gate area. As opposed to the Al–SiO2–Si system, we find that in poly–Si–SiO2–Si structures both the φMS(x,y) and the VFB(x,y) distributions are practically uniform.