Electrical properties of nonalloyed Ni/Au ohmic contacts to laser-irradiated p-GaN
We have investigated the KrF excimer laser-irradiation effect on the electrical properties of nonalloyed Ni/Au contacts to p-GaN. It is shown that the samples that were laser-irradiated in N2 ambient produce higher sheet carrier concentrations and lower sheet resistances as compared with those of the as-grown samples. Consequently, the contacts to the laser-irradiated samples yield significantly low specific contact resistance as compared to the as-grown sample. Experimental and calculation results show that field emission is responsible for the current flow for the N2-irradiated sample. It is, however, shown that for the as-grown sample, the current flow is due to thermionic emission.
KeywordsOhmic Contact Contact Resistivity Specific Contact Resistance Electronic Transport Mechanism Effective Skin Depth
This work was supported by the basic research program of the Korea Science & Engineering Foundation (Grant no. R01-2006-000-10904-0).
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