Fabrication of precision quantized Hall devices

We have fabricated metrological-quality quantized Hall devices. The devices are GaAs/AlGaAs heterostructures photolithographically etched from wafers grown by molecular beam epitaxy (MBE), with evaporated AuGeNi contacts. Step 2 centers are at 7.6 and 9.7 tesla, and currents of more than 100 /spl mu/A can be carried on steps 2 and 4. The contacting has been optimized to give contact resistances of 2-3 m/spl Omega/.