Defect detection in nano-scale transistors based on radio-frequency reflectometry

TL;DR

This paper demonstrates radio-frequency reflectometry for detecting charge defects in silicon single-electron transistors at cryogenic temperatures, revealing oscillations from unintended floating gates and enabling detailed defect spectroscopy.

Contribution

It introduces a novel application of RF reflectometry to identify and analyze charge defects in nanoscale transistors, supported by a validated charging model.

Findings

Observation of Coulomb blockade and oscillations at low temperatures

Identification of floating gate charging as the oscillation source

Potential for detailed defect spectroscopy in nanoscale devices

Abstract

Radio-frequency reflectometry in silicon single-electron transistors (SETs) is presented. At low temperatures (<4 K), in addition to the expected Coulomb blockade features associated with charging of the SET dot, quasi-periodic oscillations are observed that persist in the fully depleted regime where the SET dot is completely empty. A model, confirmed by simulations, indicates that these oscillations originate from charging of an unintended floating gate located in the heavily doped polycrystalline silicon gate stack. The technique used in this experiment can be applied for detailed spectroscopy of various charge defects in nanoscale SETs and field effect transistors