Electrodeposited Pt and sputtered NJ/Pt contacts to p-GaN (p =4.6×10↑(17) cm↑(-3) are reported and compared to sputtered NJ. Pt, and NJ/Au contacts and electron beam and thermally evaporated Ni contacts. Sequential rapid thermal annealing was employed with samples receiving an initial five minute heat treatment of 400℃ followed by I min anneals at 500. 600, arid 700℃. all under flowing N↓(2). Plots of current versus voltage for all contacts showed nonlinearity through the origin as deposited and for all annealing conditions. Extracted values of specific contact resistance are thus determined using the measured resistance for a given value of applied current. The lowest contact resistivity was reproducibly provided' by the electrodeposited Pt contacts. After a I rain anneal at 600℃, a contact resistivity of 1.50×10↑(-2)Ωcm↑(2) was obtained using the circular transmission line method at a measurement current of 10 mA. Sputtered Ni/Pt. contacts provided a contact resistivity of 1.81×10↑(-2)Ω em↑(2) at 10 mA after a 1 min anneal at 600℃. while all other metallizations yielded contact resistivities from 3-4×10↑(-2)Ωcm↑(2). Possible reasons for the lower contact resistivity of the electrodeposited contacts are discussed. # 1998 American Institute of Physics. S0003-6951 (98)02149-4
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