| abstract |
A method and apparatus for determining the thickness of an interfacial oxide film intermediate to a polysilicon layer of a first conductivity type and a silicon substrate of a second conductivity type supporting a p-n junction. Radiant energy, preferably in the form of light, is directed on to the top surface of the polysilicon layer thereby stimulating carriers which concentrate at the interfacial oxide film, allowing the excited carriers to diffuse across the oxide film, and creating a short circuit, the magnitude of which is inversely related to the thickness of the interfacial oxide film. |