Thin Metal Film Sensors

Abstract

During the last decade some progress have been made in the field of sensors using thin film techniques.In particular thin metal film strain gauges and thin film temperature sensors based on the temperature dependent resistivity of metal are now commonly used. But changes in other transport parameters with various measurands are also useful for the design of metal film sensors. Difficulty arises in thin film techniques when structural defects are frozen in films.Intensive theoretical investigations are carried out to explain the effect of grain-boundary and external surface scatterings on transport parameters. Accordingly the main results are presented to specify the influence of film structure on the sensor performance. The grain-boundary effects are discussed according to applications of metal film sensors. Theoretical predictions are analyzed in terms of sensitivity, thermal stability and long term behavior. But other problems induced by the presence of grain boundaries or point defects are also discussed, in particular problems associated with bulk diffusion, electromigration induced failures or intrinsic stresses.

Ultrathin metal oxidation for vacuum monitoring device applications

“…Their electrical properties 1, 2, morphology 3 and oxidation kinetics 4 were studied in terms of suitability as sensor. The latter aspect was summarized by Tellier 5 concerning sensing of gases, magnetic properties, thermal effects etc by thin metal films. Furthermore, great attention was dedicated to metal oxidation to understand the mechanisms and kinetics 6–11.…”

Strain effects in film materials based on metals

“…Various aspects of this problem are analyzed in the literature. Theoretical basis of sensorika for monolayer films set in work [1] in which the features of electronic properties of metal films that are widely used in sensors of temperature, strain and Hall effect. Resulting in the equations for electrical conductivity, thermoelectric power, Hall coefficient and strain coefficient of resistivity, which takes into account all possible mechanisms of electron scattering (by phonons and defects of the crystal structure, at external surfaces of the film and at the grain boundaries) can accurately predict the electronic properties of the films.…”