ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The specific contact resistance (rc) of NiGeAu and PdGeTiPt ohmic contacts to n-GaAs and TiPd and PdGeTiPt ohmic contacts to p+-GaAs were determined as a function of temperature between 4.2 and 350 K. The low rc obtained for some of the contacts at 4.2 K implies that much of the total contact resistance measured at 4.2 K in two-dimensional electron gas structures lies across the n–n heterojunction(s) in series with the metal semiconductor junction. Although NiGeAu contacts have a lower contact resistance to n-GaAs, PdGeTiPt contacts, which have much better edge definition, can be substituted for the NiGeAu when they are properly annealed. Also, contacts with low rc values at 4.2 K can be made to p+-GaAs using either TiPd or properly annealed PdGeTiPt contacts. The rc versus temperature curves for the TiPd and alloyed NiGeAu contacts fit the field emission model. The other contacts have a larger temperature dependence suggesting that tunneling occurs via thermionic field emission directly through the barrier or via defect states. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.116984
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