Improved n contact and series resistance in InP/InGaAs heterostructures by Si ion implantation demonstrated on junction field-effect transistors

The reduction of contact and series resistances in an n-type InP/InGaAs heterostructure by a multiple-energy Si implantation is described. AuGe/Au was used as an n contact metallization on the InP top layer. The contacts and the implanted layers were electrically characterized. With an electron concentration of 3×1018 cm−3 corresponding to a sheet resistance of 15.6 Ω/⧠ a contact resistance of 0.026 Ω mm was obtained. The application to a junction field-effect transistor leads to a significant improvement of the device characteristics with the transconductance increasing from 64 to 140 mS/mm due to reduced series resistances.