Pt/Ti Ohmic Contact to p sup (++) -InGaAsP (1.3microns) Formed by Rapid Thermal Processing.

Nonalloyed ohmic contacts of evaporated Pt/Ti to p-InGaAsP (lambda sub g = 1.3microns) with different Zn doping levels ranging 5 x 10 sup (18) - 2 x 10 sup (19) have been fabricated by rapid thermal processing. These contacts showed ohmic behavior prior to any heat treatment with a specific contact resistance of 4 x 10 sup (-3) omega cm sup 2 for the lowest doping level and 1 x 10 sup (-4) omega cm sup 2 for the highest level. A decrease in the specific resistance was achieved by supplying rapid thermal processing to the contacts, while the lowest values were observed on all the contacts as a result of heating at 450C for 30 sec. The lowest resistance of 1 x 10 sup (- 6) omega cm sup 2 was achieved at the contact that was formed on the 2 x 10 sup (19) cm sup (-3) Zn doped InGaAsP layer. Measurements of the conduction activation energy yield a good linear dependence of the specific resistance on temperature in all the contacts as deposited and after the different heat treatments.