A microfabricated sensor for thin dielectric layers

TL;DR

This paper introduces a microfabricated capacitor sensor capable of measuring ultra-thin dielectric layers, including atomic-scale solid xenon, with high sensitivity and dynamic control in various environments.

Contribution

It presents a novel microfabricated sensor design for detecting and controlling ultra-thin dielectric layers, including atomic layers, with applications in cryogenic conditions.

Findings

Capable of measuring single atomic layers.

Successfully grown and stabilized atomic-thin solid xenon layers.

High sensitivity capacitance readout enables dynamic layer control.

Abstract

We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance read out in a feedback system onto environmental parameters, coatings of few layers can be dynamically maintained. We discuss the design, read out and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath.