Low-resistance ohmic contacts to p-type GaAs using Zn/Pd/Au metallization

We have fabricated the low resistance ohmic contacts to p-type GaAs. Specific contact resistances as low as 7 × 10
^-7
Ω.cm
²
have been obtained for contacts prepared by heat treating Zn/Pd/Au metallizations deposited on p-type epitaxial GaAs layers with an acceptor concentration of 1.5 × 10
¹⁹
cm
^-3
. These contacts are reproducible, simple to fabricate, exhibit excellent adhesion, and have a uniformly smooth surface morphology.