A preparation procedure based on localized electrochemical oxidation unites multiple metal-insulator-semiconductor (MIS) junctions (also arrays) in a single device. The "stepped MIS" enables a comparative study of several MIS junctions of different oxide thicknesses on one silicon wafer. We present a Si-SiOx-Au four-step device with oxide thicknesses of 0, 1, 2.5, and 4 nm. The samples are characterized by internal photoemission using variable wavelengths (300-1100 nm). The "1 nm" junction shows an increased photosensitivity compared to the "0 nm" junction (metal-semiconductor system). The internal photoemission drops by 2 orders of magnitude when increasing the oxide thickness from 1 to 4 nm. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3242215] All rights reserved.