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HL: Fachverband Halbleiterphysik

HL 49: Optical Properties

HL 49.7: Vortrag

Donnerstag, 25. März 2010, 11:15–11:30, H14

Optical and electrical properties of metal-insulator-semiconductor devices with stepped insulator layer — •Wolfgang Brezna¹, Jürgen Smoliner¹, Kevin Stella², Domocos Kovacs², and Detlef Diesing² — ¹Institut für Festkörperelektronik, Technische Universität Wien — ²Institut für Physikalische Chemie, Universität Duisburg Essen

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(n-type)-SiO_x-Au four-step device with oxide thicknesses of 0, 1, 2.5, and 4 nm. Each step is partially covered with a 20 nm thick Au-electrode. The samples are characterized by internal photoemission using variable wavelengths (300 -1600 nm) and capacitance - voltage experiments. The "1 nm" junction shows an increased photo-sensitivity compared to the "0 nm" junction (MS system). The internal photoemission drops by two orders of magnitude when increasing the oxide thickness from 1 to 4 nm. The photoemission is increased by two orders of magnitude, when the sample is biased by 1 Volt in the depletion region (reverse voltage direction).