Transmission line model (TLM) method study of nanostructural AuGeNi/n-GaAs ohmic contact layer for different substrate deposition temperature

Because of the importance of ohmic contact in semiconductor devices, in this study, AuGeNi thin films were deposited by thermal evaporation technique at substrate deposition temperature from 80 °C to 230 °C and annealed at the same conditions. Then contact resistivity and surface morphology was investigated. Surface morphology was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The compositions of different zones have been determined by use of x- ray Energy-Dispersive Spectrum (EDS) analysis. Contact resistivity of the samples is measured using a conventional Transmission Line model (TLM) method. So from the I-V curves and the other mentioned analysis results, it is concluded that the sample which was deposited at 180°C indicates the best electrical and morphological properties.