Rapid IR lamp alloying of nickel-based ohmic contacts on n-GaAs

Abstract

A rapid IR lamp system has been used to alloy nickel-based ohmic contacts to n-GaAs for source-drain regions of metal-semiconductor field effect transistors. For a Ge/Au/Ni/Au metallization system isochronal and isothermal studies have indicated an optimum alloying “window” of 700–720 K and times of 3–5 s to yield a contact resistance of 0.14ω mm. Isochronal studies on the Ni/Au/Ge/Au/Ni/Au system have indicated an optimum alloying temperature of 630–660 K for the slow ramp rate graphite strip heater and a temperature of 690–710 K for the fast ramp rate IR lamp system, yielding contact resistances of 0.09ω mm and 0.10ω mm respectively. This is the first report on the investigation of alloying of nickel-based ohmic contacts using a rapid IR lamp system. Further, we have demonstrated for the first time the use of a production-line-compatible, commercially available rapid alloying system.