Design and Development of Surface Modified p and n Type Silicon Sensor for Nitrogen Gas Flow Measurement

TL;DR

This study demonstrates that surface modification of silicon wafers with OTS SAM enhances their sensitivity to nitrogen gas flow, leveraging Bernoulli and Seebeck effects, with potential applications in flow measurement.

Contribution

The paper introduces a novel surface modification technique using OTS SAM on silicon wafers to improve gas flow sensing capabilities at subsonic velocities.

Findings

OTS SAM coated wafers show higher sensitivity than uncoated wafers.

Surface modification improves thermal stability and hydrophobicity.

Flow-induced voltage correlates with nitrogen gas flow velocity.

Abstract

We report a gas flow driven voltage generation of Octyltrichlorosilane (OTS) molecules self assembled on silicon wafers (Si wafers). OTS Self assembled Monolayer (SAM) has been coated on both p-type and n-type doped silicon wafers (p-Si and n-Si wafers) using dip coating method. We have measured the flow induced voltage generation on OTS SAM coated Si wafers/ Uncoated Si wafers at modest gas flow velocities of subsonic regime (Mach number < 0.2) using national instruments NI-PXI-1044 Workstation. The gas flow driven voltage generation is mainly due to the interplay mechanisms of Bernoulli principle and Seebeck effect. The surface morphology of OTS SAM coated p-Si and n-Si wafers were characterized by SEM analysis. In this study, our results shows that OTS SAM coated p-Si and n-Si wafers shows better sensitivity towards nitrogen gas flow when compared with the uncoated Si wafers. OTS SAM also exhibits high thermal stability and hydrophobicity.