
12-6 Sensors and Sensor Technology
and hence the Schottky barrier height. is change in the Schottky barrier height causes a shi in the
I–
V
ch
aracteristics
. e re
sponse
ca
n
be me
asured
as th
e
ch
ange
in vo
ltage
wh
en
th
e
di
ode
is op
erated
at c
onstant
b
ias
c
urrent
[
6]
.
A MO
S
ca
pacitor
is th
e
sim
plest
MO
S
de
vice
an
d
a cr
oss-sectional
vi
ew
of a ty
pical
MO
S
ca
pacitor
is sh
own
in Fi
gure
12.8. A th
in
ox
ide
la
yer
is sa
ndwiched
be
tween
a me
tal
la
yer
(p
alladium
or pl
ati-
num)
an
d
a sil
icon
su
bstrate
la
yer
. e ab
sorption
of hy
drogen
an
d
th
e
ch
emical
re
actions
at th
e
MO
X
in
terface
ca
use
a ch
ange
in th
e
C–
V
ch
aracteristics
of th
e
ca
pacitor
an
d
sh
i
th
e
a