AU PD TE OHMIC CONTACTS ON N-TYPE INP

Au/Pd/Te contacts on n-type InP have been studied and a contact resist ance of 1 X 10(-4) OMEGA-cm2 was achieved on a doping level of 4 x 10( 15) CM-3 and 1 x 10(-6) OMEGA-cm2 on 4 x 10(18) cm-3. This contact sys tem reacts with the InP in a solid phase interaction to form an interf ace region of only 44 nm in thickness. A separate study of the interac tion of Te with InP by X-ray diffraction and electrical sheet resistan ce measurements revealed that In2Te3 grew epitaxially on the InP. We b elieve this compound facilitates the ohmic contact formation by formin g a thin layer doped with the released phosphorus and thus forms the i nterface between the InP and remaining elemental Te. Other electrical measurements show that Pd acts as a barrier during annealing preventin g interaction of the Te and Au resulting in an acceptable post process ing resistivity of 18 muOMEGA-cm for the ohmic contact metallization.