OHMIC CONTACTS OF AU AND AG TO P-GASB

Evaporated contacts of Au, Au(Zn), Au(In, Zn) Au(Ge), Ag, Ag(Zn), Ag(Ge), Ag(Sn), Ag(In), In, In(Zn), ln(Ge), and Al have been studied for p-GaSb(100) doped in the range 8 x 10(16)-1 x 10(19) cm-3. Annealing was typically at a temperature 250-350-degrees-C for 10-30 min. A transmission line and other methods were used to determine the specific contact resistivity. For material of a carrier doping density 10(18) cm-3 the contacts exhibited values about 5 x 10(-5) OMEGA cm2. For other dopings the contact resistivity tended to be inversely proportional to the doping density, and at 1 x 10(19) cm-3 the value was 5 x 10(-6) OMEGA cm2. Ag contacts were stable in resistance for at least 100 h at 350-degrees-C and therefore may be expected to have little change over many thousands of hours at 70-degrees-C. The Au based contacts however began to increase in resistance after 30 h at 250-degrees-C. Models for the calculation of specific contact resistivity have been applied to p-GaSb and comparison with experimental results made.