Properties of alloyed AuGeNi-contacts on GaAs/Ga/AlAs-heterostructures
A reproducible and robust techique of contacting GaAs/GaAlAs heterostructures using an evaporated AuGeNi alloy has been developed. The behavior of the electrical contacts to the two-dimensional electron gas has been studied in the quantum Hall regime. Contact resistance values of typically 10-50 m-OMEGA are obtained which are stable with time and thermal cycling. This type of contact is therefore well suited to be used for precision measurements of the quantized Hall resistance.