Photoelectron–grain boundary scattering in al films of MOS structures

Internal photoemission is studied in MOS structures by measuring the photocurrents obtained when the metal electrode – a thin Al film – is negatively polarized with respect to the Si slice and photons hv higher than the SiO2–Al interface barrier are impinging upon the structure from the metallic side. The data obtained by varying the thickness of the metal film are analyzed and a mean free path due to electron-grain boundary scattering of the order of the grain size is obtained.