Limiting Regimes for Electron-Beam Induced Deposition of Copper from Aqueous Solutions Containing Surfactants

TL;DR

This paper investigates the regimes of copper deposition via electron-beam induced processes in aqueous solutions, highlighting the transition points and efficiency, with implications for better control in nanofabrication.

Contribution

It introduces substrate modifications to control liquid layers and characterizes different deposition regimes, including transition points and efficiency in environmental SEM.

Findings

Identified transition from electron to mass-transport limited regimes

Observed high deposition efficiency of 1 to 10 copper atoms per electron

Characterized aggregated and high-aspect ratio deposit regimes

Abstract

Focused electron beam induced deposition of pure materials from aqueous solutions has been of interest in recent years. However, controlling the liquid film in partial vacuum is challenging. Here we modify the substrate to increase control over the liquid layer in order to conduct a parametric study of copper deposition in an environmental SEM. We identified the transition from electron to mass-transport limited deposition as well as two additional regimes characterized by aggregated and high-aspect ratio deposits. We observe a high deposition efficiency of 1 to 10 copper atoms per primary electron that is consistent with a radiation chemical model of the deposition process.