Thermally stable and nonspiking Pd/Sb(Mn) ohmic contact to p-GaAs

A thermally stable, nonspiking ohmic contact to p-GaAs has been developed based on the solid-phase regrowth mechanism. The contact metallization consists of a layered structure of Pd(250 Å)/Sb(100 Å)/Mn(10 Å)/Pd(250 Å)/p-GaAs. Thermal annealing of the contact between 300 and 600°C for 10 s yields contact resistivities in the range of low 10-6 Ω cm2 on substrates doped to 2.5×1018 cm-3. A contact resistivity of 4.5×10-7 Ω cm2 can be obtained after annealing at 500°C on samples with a doping concentration of 4.5×1019 cm-3. The contact metallization remains uniform in thickness and the contact interface is flat after the contact is formed. The consumption of the substrate is limited to less than a hundred angstroms. Contact resistivities are stable at 400°C.