A reliable fabrication technique for very low resistance ohmic contacts to p-InGaAs using low energy Ar/sup +/ ion beam sputtering

A fabrication technique for non-alloyed Au/Pt/Ti ohmic contacts to p-InGaAs (N/sub A/=1*10/sup 20/ cm/sup -3/) is discussed. The semiconductor surface is cleaned by Ar/sup +/ ions immediately followed by the metal deposition by electron beam evaporation. The low energy (60 eV) Ar/sup +/ ion etching removes the residual oxide layer existent on the semiconductor surface. The contact is formed by rapid thermal processing (RTP) at 400+or-C. It is shown that extremely low specific contact resistances (r/sub c/ =6*10/sup -8/ Omega -cm/sup 2/) can be achieved, even for 2.5 mu m contact widths, and that the contacts produced exhibit excellent homogeneity and improved uniformity over wet chemically pre-cleaned ones.<>