Pb/Zn/Pd ohmic contacts to p-GaP

Low resistance ohmic contacts have been fabricated and analyzed to Zn-doped p-GaP using an annealed Pd/Zn/Pd metalization. It has been found that the Pd/Zn/Pd multilayer structure shows good ohmic characteristics after heat-treatment. The results show that the alloying temperature and alloying time are very important factors for the quantity of the ohmic contact layer. When the surface hole concentration of the p-GaP is 2 × 1017 cm−3, a specific contact resistance of 6 × 10−5 Ω cm−2 has been obtained at the optimum alloying temperature of 550°C and the optimum alloying time of 3 min.