화학공학소재연구정보센터
Thin Solid Films, Vol.317, No.1-2, 173-177, 1998
AES, AFM and TEM studies of NiCr thin films for capacitive humidity sensors
A few hundred nanometre thick NiCr layers form the capacitance humidity sensor electrodes. The electrodes must have the adequate electric resistance, low mechanical tensions, proper elasticity coefficient in order to prevent the corruption of the NiCr-dielectric layer joint when the dielectric is saturated by the water vapour. The upper electrode must be permeable for the water vapour in order to permit the water vapour to diffuse into the dielectric. The sufficient permeability of the NiCr film is obtained by an evaporation under the deposition incidence angle of 75 degrees. The deposition angle is defined as the angle between the normal to the substrate surface and the normal to the evaporating source. The detailed results of NiCr thin film investigation by AES, AFM and TEM are presented. The NiCr thin films are non-homogeneous and are strongly dependent on deposition conditions. A different vapour pressure of Ni and Cr during the deposition process has a dominant influence on chemical composition of the NiCr thin films. The NiCr thin film evaporated under 0 degrees incidence angle is cracky, while the layer evaporated under 75 degrees incidence angle has the columnar structure.