Coulomb blockade in a Si channel gated by an Al single-electron transistor

TL;DR

This paper demonstrates Coulomb blockade effects in a silicon channel gated by an aluminum single-electron transistor, revealing strong electrostatic coupling and single-electron phenomena in a nanoscale MOSFET system.

Contribution

It introduces a novel integrated system where an Al single-electron transistor gates a Si MOSFET, enabling direct observation of Coulomb blockade and charge interactions at the nanoscale.

Findings

Observation of conductance oscillations due to Coulomb blockade

Correlation between Al transistor steps and Si transistor charging events

Electrostatic model showing strong coupling between islands

Abstract

We incorporate an Al-AlO_x-Al single-electron transistor as the gate of a narrow (~100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET). Near the MOSFET channel conductance threshold, we observe oscillations in the conductance associated with Coulomb blockade in the channel, revealing the formation of a Si single-electron transistor. Abrupt steps present in sweeps of the Al transistor conductance versus gate voltage are correlated with single-electron charging events in the Si transistor, and vice versa. Analysis of these correlations using a simple electrostatic model demonstrates that the two single-electron transistor islands are closely aligned, with an inter-island capacitance approximately equal to 1/3 of the total capacitance of the Si transistor island, indicating that the Si transistor is strongly coupled to the Al transistor.