Spatially resolved random telegraph fluctuations of a single trap at the Si/SiO2 interface

TL;DR

This study uses electrostatic force microscopy to spatially resolve and analyze the behavior of individual traps at the Si/SiO2 interface, revealing their impact on noise and device performance.

Contribution

It provides the first spatially resolved measurements of random telegraph noise at the Si/SiO2 interface, linking defect fluctuations to device noise characteristics.

Findings

Localized two-state fluctuations at interfacial traps.

Bias-dependent rates and amplitudes of fluctuations.

Correlation between defect fluctuations and 1/f noise.

Abstract

We use electrostatic force microscopy to spatially resolve random telegraph noise at the Si/SiO$_2$ interface. Our measurements demonstrate that two-state fluctuations are localized at interfacial traps, with bias-dependent rates and amplitudes. These two-level systems lead to correlated carrier number and mobility fluctuations with a range of characteristic timescales; taken together as an ensemble, they give rise to a $1/f$ power spectral trend. Such individual defect fluctuations at the Si/SiO$_2$ interface impair the performance and reliability of nanoscale semiconductor devices, and will be a significant source of noise in semiconductor-based quantum sensors and computers. The fluctuations measured here are associated with a four-fold competition of rates, including slow two-state switching on the order of seconds and, in one state, fast switching on the order of nanoseconds which is associated with energy loss.