In Situ Surface Treatment of GaAs ( 100 ) Wafer in Metal Salt Electrolytes for Fabrication of Schottky Contact

The electrochemical behavior of n-type GaAs(100) was investigated to find an optimum condition for in situ surface treatment in Ni salt electrolytes prior to the fabrication of Ni/GaAs Schottky contacts by the wet method. Commercial machine-polished GaAs wafers with damaged crystal lattices did not show photoresponse and behaved exactly the same as a Ga metal electrode in the region of -0.1 to +0.5 V vs. Ag/AgCl. Photoresponse was observed after the removal of the damaged surface layer in H 2 SO 4 -H 2 O 2 -H 2 O. The in situ surface treatment of GaAs was done by photoelectrochemical etching at +0.1 V in acidic nickel salt electrolyte followed by the fabrication of a GaAs/Ni Schottky contact by applying negative potentials