RF reflectometry for readout of charge transition in a physically defined p-channel MOS silicon quantum dot

Abstract

We have embedded a physically defined p-channel silicon MOS quantum dot (QD) device into an impedance transformer RC circuit. To decrease the parasitic capacitance of the device which emerges in MOS devices that have a top gate, we fabricate a new device to reduce the device's top gate area from 400 μm² to 0.09 μm². Having a smaller top gate eliminates parasitic capacitance problem preventing the RF signal from reaching QD. We show that we have fabricated a single QD properly, which is essential for RF single-electron transistor technique. We also analyze and improve the impedance matching condition and show that it is possible to perform readout of charge transition at 4.2 K by RF reflectometry. This will enable fast readout of charge and spin states.