Development and Performance of the Nanoworkbench: A Four Tip STM for Electrical Conductivity Measurements Down to Sub-micrometer Scales

TL;DR

This paper introduces the nanoworkbench, a sophisticated four-tip STM integrated with SEM and MBE capabilities, enabling precise electrical conductivity measurements at sub-micrometer scales in ultra-high vacuum conditions.

Contribution

The paper presents the development of a multi-chamber nanoworkbench system combining STM, SEM, and MBE for localized electrical measurements and device fabrication at microscopic scales.

Findings

Successful STM imaging on graphite

Four-point probe conductivity measurements on SOI

Demonstration of local FET creation

Abstract

A multiple-tip ultra-high vacuum (UHV) scanning tunneling microscope (MT-STM) with a scanning electron microscope (SEM) for imaging and molecular-beam epitaxy growth capabilities has been developed. This instrument (nanoworkbench) is used to perform four-point probe conductivity measurements at micrometer spatial dimension. The system is composed of four chambers, the multiple-tip STM/SEM chamber, a surface analysis and preparation chamber, a molecular-beam epitaxy chamber and a load-lock chamber for fast transfer of samples and probes. The four chambers are interconnected by a unique transfer system based on a sample box with integrated heating and temperature-measuring capabilities. We demonstrate the operation and the performance of the nanoworkbench with STM imaging on graphite and with four-point-probe conductivity measurements on a silicon-on-insulator (SOI) crystal. The creation of a local FET, whose dimension and localization are respectively determined by the spacing between the probes and their position on the SOI surface, is demonstrated.