High Precision Flow Compensated Thermal Conductivity Detector for Gas Sensing with Read-out Circuit

Master thesis (2015)

Authors

Contributors

G. De Graaf (mentor)
Programme
M.Sc in Microelecronics / Electronic Instrumentation Laboratory (EEMCS) (TU Delft)
Copyright: © 2015 Abarca, A.N.
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Published Date

25-09-2015

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Programme

M.Sc in Microelecronics / Electronic Instrumentation Laboratory

Abstract

In this work, a novel approach is presented for in-line flow compensation using a dual-Thermal conductivity detector (TCD). TCDs demonstrate a flow dependence and require a calibration at a fixed flow rate. The dual-TCD is composed of two thin-film sensors on membranes in parallel on the same chip. Both are laterally identical, but with a significantly difference on quasi-static sensitivity to the thermal conductivity of the gas by a different sample chamber. The result is a reduced flow rate dependence when differentially operated. The device is fabricated using both bulk and surface micromachining. The design, simulations, fabrication and measurements of the TCD are presented.