Ultra-low Resistance Contacts to GaAs/AlGaAs Quantized Hall Resistors

摘要

Since the adoption in January 1990 of the quantized Hall resistance (QHR) as a practical representation of the unit of resistance by the Consultative Committee on Electricity (CCE) [1],national standards laboratories around the world have begun to use quantized Hall resistors to provide the basic unit for their resistance calibration services.Most of the devices in use at national standards laboratories are prepared from GaAs/AlGaAs heterostructures because of the relatively ready availability of high quality material.While these devices are similar in structure to high electron mobility transistors (HEMTs)-they use essentially the same type of heterostructure,and the contacts are similar to the source and drain contacts on HEMTs-they must meet far more stringent criteria [2].