EXTENDING THE HIGH-FREQUENCY LIMIT OF A SINGLE-ELECTRON TRANSISTOR BYON-CHIP IMPEDANCE TRANSFORMATION

We have fabricated an aluminum single-electron transistor (SET) and ch aracterized it at frequencies up to 700 kHz. The relatively high frequ ency was achieved by reducing the capacitance at the SET output. The S ET was bonded to an InP high-electron-mobility transistor (HEMT), and biased through a small (<100 mu m) on-chip resistor made of 150 tunnel junctions in series. The output voltage swing of the SET decreases wi th increasing HEMT current because of heating. Thus, the gain of the H EMT was limited and therefore the noise performance of the system was limited to 3x10(-4)e/root Hz at 10 kHz.