Hydrogen sensitive mos-structures part 2: characterization

Abstract

This paper deals with several methods which can be used to characterize gas sensors based on a catalytic metal as a gate of a semiconductor device. The main effort is to demonstrate how different device parameters can be investigated. We show examples of long-term phenomena, of different kinetic behaviours and of properties depending on the structure of the metal film. The use of a Kelvin probe to separate processes on the metal surface and at the metal-insulator (semiconductor) interface is described. Some phenomenological chemical reaction models are also discussed. The main thrust of the paper is in the description of the hydrogen sensitivity and long-term behaviour of non-porous Pd-films at elevated temperatures. Some consideration is also given to porous Pd-films and to room temperature operation. The paper is of an exploratory nature and does not give the solution to all questions related to Pd-MOS structures. We intend, however, to demonstrate how and why certain parameters are measured. © 1982.