Ion Sensitive Field-Effect Transistor - ISFETmicrosens.ch/products/pdf/MSFET_Datasheet.pdfMICROSENS...
Transcript of Ion Sensitive Field-Effect Transistor - ISFETmicrosens.ch/products/pdf/MSFET_Datasheet.pdfMICROSENS...
MICROSENS
Product S ecific Data Sheet
Ion Sensitive Field-Effect Transistor - ISFET
• MSFET 3310 Si3N4 gate
• MSFET 3320 AI203 gate
• The ISFET devices are realized with
microelectronic technology compatible
with CMOS processes.
• Si3N4 and AI203 insulating gate
ISFET base devices are measuring the
pH value in a wide range from basic toacidic solutions
ISFET principle
• The measurement of ion concentra
tions such as K+, Ca2+ is realized with
an additional organic ion-selective
membrane photopolymerized on the
insulating gate of the sensor.
ISFET device
Legend:
1. drain
2. source
3. substrate
4. Si02 insulator
5. Si3N4 or AI203insulator
6. meta 1contacts
7. reference electrode
8. ion selective mem
brane (option)
9. encapsulant
ISFET encapsulated on a ceramic based Printed
Circuit Board (PCB)
s e n S 0 r s p e c i f c a t.1 o n S
pH
K+, Ca2+, Mg2+,with additional ion selective membrane
Measured chemical
speCies
MSFET3310 MSFET3320
• Sensor construction (3310)(3320)
Base structure
• Sensor base materials
Silicon, polysilicon, Si3N4,AI203
• Technology used
4" planar CM OS process
Sensitive membrane• pH-sensitive material
Si3N4AI203
• ion selective membrane
lonophores doped polysiloxane
Sensor dimensions.Chip dimensions
0.6 x 4.5 x 0.3 mm
• Packaged sensor: - DIL
20 x 8 x 2 mm (pins not included)
- PCB (typical)
50 x 4 x 1 mm
• Sensor SpecificationsSensitivity:
• pH:
50 mV/pH unit
• K+:
58 mV/pK
• Ca2+30 mV/pCa
Concentration range:
• pH:
1 - 12
• K+:
10-7 - 1 (M)
• Ca2+
10-6 -1 (M)
Accuracy
0.01 pH (or 0.1 %)
Stability
0.1 pH/day (or 1%)
Operating temperature
-450 C + 1200 C
Response time
< 1 sec. (90%)
• Reference-electrode
Ami n iaturized Ag/Ag C 1 Reference
Electrode is realized together with the
packaged ISFET chip acting as metal
gate electrode and providing a stable
reference potential. For specific applica
tions, an Integrated Reference
Electrode (IRE)* has been developedwhich is manufactured on the same
chip together with the ISFET.
The Ag/AgCI electrode is then deposi
ted on the reversed side of the ISFET
device and a silicon-structured cavity is
containing the KCI Electrolyte. The
liquid junction of the IRE is obtained by
a porous silicon membrane manufactu
red on the ISFET front-si de chip.
* Patent US 06/7757669.
Typical Sensor Character stics
15
_ 1.3
LU"'"--~-=/2:. ~. ~-_.-
<n
en> 97+/
>270
..s<D
210<n c0~ 150t;:; ~ 90.0+"'"
30.0
.5
K+ ion selective membranes on planarCMOS ISFET
Photopolymerised ion-selective membranes
Highly selective organic membranes for differention-concentration measurements such as K+,
Ca2+, Mg2+ are deposited and structured with a
wafer-scale photolithographie technique. Thanks
the very good adhesion and stability of these
membranes the specifie ion selective FETcan be
used for ion-concentration monitoring with a good
sensitivity and a linearity within a wide range ofconcentration down to 10-6 M.
o 1 2 3 4 5 6 7 8 9 10 11 1213 14
pH
AI20J gate ISFET pH sensitivitySaturated calomel reference electrode
buffer solutions pH 2 ta 11
Siope = 53.7 mV/pH
Vds = 1 V Ids = 50 ~A
Potassium membrane ISFET
DlL packaged ISFET multi-sensor devicefor flow through measurement
Flow through cell measurement configuration
The ISFETsingle or multi-sensor chip is mounted,
on a standard DIL package. The disposable sensor
can be used for single or multiple use in a flow
through cell measurement system.
3.000 , ,500>2.900
400.s>
m.""
- CQJ
2.800 300El
:>0c-mQJ
."" 200>
c 2.700 .~QJ a Qjc-
a:::
y..C
2.600 100-QJQJ :>a:::
2.500
03
456789
pH
ISFET pH sensitivityAI203 gate device referenced towards satura
ted calomel electrode (SCE) and Ag/AgCI
integrated reference electrode (IRE)
Vds = 1.5 V Ids = 100 ~A
Calcium membrane ISFET
>180
3Slope: 30.0 mV / pCa
..s<D
<n 140c 0sriO'
100>- LW~+
50.0
NroU 20.0
-5.00 -4.00 -3.00 -2.00
LOG a (K)
-1.00 -5.00 -4.00 -3.00 -2.00
LOG a (Ca)
-100
ISFET K+ ion concentration sensitivity ISFET Ca2+ ion concentration sensitivity
lmMICROSENS
Packaging
• ISFET-chips are mounted, micro
bounded and sealed in hermetic encap
sulant to be used as sensor devices for
different applications. Application spe
cifie packages, such as hermetically
sealed PCB (Printed Circuit Board) as
weil as OIL (Oual ln Line) standard
package, are available.
ISFET encapsulated in a catheter for
medical "in vivo" pH monitoring
PCB or Kapton based circuits boards are used
for the packaging of pH sensors in
2 mm diameter catheters.
Dil Packaged ISFET for flow through
cel! measurement system.
Specifie OIL packaged ISFET are manufactu
red with silicone encapsulant providing on
hermetic interface with the tubing of a flow
through cell system.
1
1
1
1 1
L ~ J
Ids = 100 ~A
rel
0
c::=::Jflcr---..L + Vds = 1.0V 1~ substrate
G
---r-- Vd > Vs
S
Vgs> 0
Electrical connections of ISFET devices
Legend:0: Drain
S: Source
Su b : Su bstrate
G : Reference electrode
Schematic electronic circuit diagram
This circuit configuration is used for a
constant drain current operation of the ISFET
device.
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