Multilayer CrPtCr/NiAu ohmic contacts with p-type GaAs in heterojunction laser structures

Multilayer CrPtCr/NiAu metallization was deposited by sputtering in a magnetron on the p-type side of GaAs in a pulsed laser heterostructure. Heat treatment at 490 °C for 3 min produced a reliable ohmic contact with a specific resistance of 10^– 6–10^– 5 Ω · cm², depending on the substrate doping. Secondary-ion mass spectroscopy and Rutherford backscattering methods were used to study the mechanism of formation of a contact.