Photoelectric measurements of the local values of the effective contact potential difference in the MOS structure

We have shown that using focused UV laser beam in photoelectric methods it is possible to measure local phi MS values over the gate area of a single MOS structure. The phi MS distribution is such that its values are highest far away from the gate edges regions, lower in the vicinity of gate edges and still lower in the vicinity of gate corners. Examples of measurement results and description of the measurement system are presented. The dependence of the phi MS value on the exposure time and the power density of UV light is discussed.