MEMS sensors for flow measurement in harsh environments
Ctrl
+
K
↑
↓
navigate
↩
select
Esc
close
Introduction
1
Literature review on flow sensing for harsh environments
1.1
Flow equations and turbulence scales
1.2
Flow measurement techniques
1.2.1
Historical overview
1.2.2
Hot wires
1.2.3
Wall shear stress sensors
1.2.4
Summary table of existing flow sensors
1.3
Adapting MEMS thermal anemometers to harsh environments
1.3.1
SiC as a material for harsh environments
1.3.2
Developments of SiC-based MEMS
1.3.3
SiC-based thermal anemometers
1.4
Objectives of this work
2
Technological developments of 3C–SiC thermal devices
2.1
Resistors from 3C–SiC films epitaxially grown on silicon
2.1.1
Development of an etching process for 3C–SiC layers
2.1.2
SiC
2.2
Electric insulation of 3C–SiC resistors
2.2.1
Producing
2.2.2
The challenge to build calorimetric sensors
2.3
Etching process of 3C–SiC thin films
2.3.1
Reactive Ion Etching
2.3.2
Bosch process
2.4
Fabrication of SiC calorimeters
2.4.1
Design
2.4.2
SoI insulation
2.4.3
Highly resistive 3C–SiC buried layer insulation
2.4.4
Transfer to borosilicate glass
2.5
Characterizations
2.5.1
Characterization setup
2.5.2
TCR measurement
2.5.3
Resistance-Power characteristic
2.6
Conditioning of hot-wire sensors
2.6.1
Development of a CTA suited for SiC hot wires
2.6.2
Frequency response assessment
3
Sensor testings in real flows
3.1
Wind tunnel testings
3.2
Wind tunnel facility
3.3
Flush-mounting of sensors on the wind tunnel wall
3.4
Wall shear stress calibration
3.4.1
The Coles-Fernholz method
3.4.2
Calorimetric response to wall shear stress
3.5
Square-wave tests
3.5.1
Theory
3.6
Overheat effect
3.7
Dynamic response
Conclusion
References
/
2 Technological developments of 3C–SiC thermal devices
/
2.2 Electric insulation of 3C–SiC resistors
#
2.2
Electric insulation of 3C–SiC resistors
#
2.2.1
Producing
<100> Si
substrate
Si
3C-SiC
BF33
3C-SiC
hetero-
epitaxy
800 nm
backside
grinding
anodic bonding
to a BF33 wafer
Au contacts
deposition
SiC dry
etching
Si isotropic
etching
50 µm
Au
Figure 2.1.
Fabrication flowchart for simple SiC suspended hot wires.
This method works but is not enough to build calorimetric probes because of lateral silicon etching.
#
2.2.2
The challenge to build calorimetric sensors
← prev
Resistors from 3C–SiC films epitaxially grown on silicon
next →
Etching process of 3C–SiC thin films