Dynamic and Static Transmission Electron Microscopy Studies on Structural Evaluation of Au nano islands on Si (100) Surface

TL;DR

This study investigates the morphological evolution of gold nanostructures on Si (100) surfaces under different annealing conditions using TEM, revealing oxide layer effects on nanostructure formation and transformation.

Contribution

It provides new insights into how vacuum conditions influence gold-silicide nanostructure formation during annealing, combining in-situ and ex-situ TEM analyses.

Findings

High vacuum annealing leads to gold silicide nanostructures.

Low vacuum annealing prevents silicide formation due to oxide barrier.

Native oxide decomposition is key to nanostructure transformation.

Abstract

Transmission electron microscopy (TEM) study on morphological changes in gold nanostructures deposited on Si (100) upon annealing under different vacuum conditions has been reported. Au thin films of thickness ~2.0 nm were deposited under high vacuum condition (with the native oxide at the interface of Au and Si) using thermal evaporation. In-situ, high temperature (from room temperature (RT) to 850\degreeC) real time TEM measurements showed the evaluation of gold nanoparticles into rectangular/square shaped gold silicide structures. This has been attributed to selective thermal decomposition of native oxide layer. Ex-situ annealing in low vacuum (10-2 mbar) at 850\degreeC showed no growth of nano-gold silicide structures. Under low vacuum annealing conditions, the creation of oxide could be dominating compared to the decomposition of oxide layers resulting in the formation of barrier layer between Au and Si.