The quantized Hall resistance (QHR) device is widely used by national metrology institutes (NMIs) as DC resistance standards. The plateau at i = 2 is practically used for DC resistance calibration, and the nominal value of QHR at this plateau is 12 906.403 5 Ω. This non-decade value requires sophisticated technology to be used for actual resistance calibration, therefore several NMIs tried to make convenient quantum resistance standards which have nominally decade values: 100 Ω, 1 kΩ, 10 kΩ and so on by combining QHR elements in series and in parallel.

We are now trying to establish the next generation standards of DC resistance, and an experimental device of quantum Hall array resistance standard (QHARS) with a nominal value close to 10 kΩ has been developed. This QHARS device consists of 266 Hall bar elements. This device will play an important role in future calibration services due to the growing demand of 10 kΩ resistance calibration.