The features of the Ni-GaAs contacts formation obtained by electrolysis and their electrophysical properties

Background. Nickel contacts based on gallium arsenide are of interest from the point of view of their application in optoelectronics. The purpose of this work is to study the contact structures of Ni p-GaAs and Ni n-GaAs. The object of the study is the electrochemical contacts of nickel to crystalline gallium arsenide. The article presents studies of the topography of homogeneous electrochemical nickel films of nanometer thickness (50-100 nm) on the surface of a semiconductor. The current-voltage characteristics of metal-semiconductor contacts are experimentally obtained. Materials and methods. The roughness of the GaAs Ni film substrate was studied using optical and probe microscopes. Nickel films were obtained using a Watts solution and a setup for the production of electrochemical structures by the drop method. To minimize the roughness of the nickel surface obtained by electrolysis, a mode of low current density was used. Using a theoretical model and experimental data, the contact resistances and their current-voltage characteristics are obtained. Results. The parameters of nickel surface roughness, which affect the operational properties of contact structures, are determined. The features of the current flow through the electrochemically obtained Ni GaAs contact are revealed. Conclusions. It is shown that the resulting Ni p-GaAs structures are ohmic, and the current-voltage characteristics of the Ni n-GaAs contacts have a nonlinear region at voltages less than 1.5 volts. It is shown that the formation of an integral nickel film on the GaAs surface is possible when the Ni layer thickness exceeds the average substrate roughness.