NO2 gas sensing studies: Impact of geometrical and physical characteristics of ohmic contacts on n-InP epitaxial sensitive layer

This paper deals with the influence of technological process steps on electrical and metrological parameters of NO2 gas sensors. The NO2 gas sensors are based on thin n-InP epitaxial layers. The NO2 gas action makes the resistance of the device, measured in parallel to the surface between ohmic contacts, increase. It is demonstrated that the methodology of fabrication modifies the geometrical and the physical parameters of ohmic contacts and the reproducibility of the devices. The impact on the gas sensors in response to NO2 is also discussed.