LOW-RESISTANCE OHMIC CONTACTS ON NITROGEN ION-BOMBARDED INP

Nonalloyed Ti/Pt/Au contacts deposited in situ onto nitrogen ion bomba rded n-type InP show contact resistivities as low as 3.4X10(-6) Omega cm2. Acceleration voltages of 100-300 V and exposure times of 3-11 min were used to remove InP native oxide and produce a shallow (less than or equal to 300 Angstrom) disordered donor layer on which ohmic conta cts were deposited. Electron diffraction patterns matching those of po lycrystalline InN were identified in this degenerately doped surface l ayer, which was further characterized by secondary ion mass spectromet ry and ion channeling. Similar layers produced by Ar ion bombardment u nder the same conditions showed much higher contact resistivities (sim ilar to 10(-4) Omega cm(2)), indicating that the InN formation is bene ficial for contact properties. (C) 1994 American Institute of Physics.