Electrical Characterisation of Ultra-thin SAM Structures

TL;DR

This study explores the electrical properties of ultra-thin self-assembled monolayers on silicon, characterizing their uniformity and potential for use in gas sensors and improved electronic devices.

Contribution

It provides a comprehensive characterization of n-alkyltrichlorosilane monolayers on silicon and investigates their application in metal-insulator-semiconductor diodes and gas sensors.

Findings

Monolayer roughness of a few Angstroms confirmed by AFM.

Sputtering deposition affects gate leakage current.

Potential for gas sensing using organic films identified.

Abstract

The way of reduction of metal oxyde semiconductor (MOS) structures is going to reach limitations and new devices have to be explored as an alternative to MOS technology. Molecular electronic and more particularly self-assembly-molecular technique on silicon substrate gives interesting results as seen in the literature. We are going to study n-alkyltrichlorosilane grafting on oxidised silicon, characterise it macroscopically with ellipsometer and goniometry measurements, and down to microscopic scale with atomic force microscopy. Once the uniformity of the monolayer is verified (roughness of few Angstr\"oms) we have tested a sputtering method deposition to form aluminium dots onto the surface. Also metal-insulator-semiconductor diodes are tested measuring both leakage current between gate and substrate and capacitance-voltage. The sputtering method deposition can be improved in order to decrease the gate leakage current and we would like to test another evaporation method. Further application we want to study is gas sensors using conjugated organic films or synthetic polymers and concerns the drift current with gas absorption.