Book Description

This report describes the research accomplished during a 14-month program of research on metal-semiconductor contacts on indium phosphide. Emphasis was placed on fabrication and characterization of ohmic contacts to p- and n-type InP using the deposition of thin metallic layers and subsequent heat treatment at elevated temperatures. Extensive use of Auger electron spectroscopy (AES) was made in order to obtain depth-composition profiles of the thin-film structures. For contact to n-type InP, three thin-film systems were investigated: Au, Ni, and a composite layer of Ni/Au/Ge. The specific contact resistance (r sub c) of the Ni/Au/Ge/In system varied in a systematic manner with heat-treatment temperature, and a minimum value of r sub c of .00003 ohm-sq cm at 325 C was found for N(D) = 3 x 10 to the 16th power/cc. Several nickel germanide phases, detected by AES and X-ray diffraction, were formed during heat treatment and were found to affect r sub c. For contact to p-type InP, a film consisting of Au/Mg was investigated. For heat treatment of the Au/Mg/InP system above 350 C, r sub c decreased with increasing signs of alloying at higher temperatures. The smoothest surface was obtained at 446 C for 50 minutes with r sub c approx. 0.0001 ohm/sq cm for N(A) = 6 x 10 to the 17th power/cc.