This paper concerns the growth and the transformation of copper layer on n- and p- InP substrates. Thus, we analyzed the electrodeposition of copper layers on InP substrates in acidic media. The laws of the growth of the copper films have been determined. Electrical and optical properties are modified by the growth of copper films. Electrochemical measurements (voltammetry and impedance are coupled to “ex-situ” techniques such as XANES and EXAFS to determine the environnment of the semiconductor surface in order to determine the interaction between the copper and the semiconductor surface atoms. Thus, it has been proved that a strong interaction exists between copper and phosphorus atoms leading to the formation of a thin inner layer of Cu₃P. The copper films grown on InP substrates in acidic media can be transferred in basic media and can be transformed electrochemically. The metallic films are reoxidized as Cu₂O, and this oxide film can be then quasi-totally reduced.