Digital Signal Processing Reference
In-Depth Information
Table 2.3
Measured resistive values obtained from pentacene resistors
Name
Size
Sample 1 (M
)
Sample 2 Mean Value (M
) R/Square (G
/
)
R
pent
,
1
140
µ
m/10
µ
m 1341
1439M
1390
19.5
R
pent
,
2
140
µ
m/25
µ
m 4223
4092M
4157
23
R
pent
,
3
280
µ
m/50
µ
m 2551
/
2551
14.5
R
pent
,
4
140
µ
m/50
µ
m 7434
6054M
6744
19
Pin #1
Pin #1
m
5µ
5µ
m
Gate
Gold
L
L
Pentacene
Pentacene
W
W
Pin #2
Pin #2
(a)
(b)
(c)
Fig. 2.23 a
Schematic
top view
of a
metal line
resistor built in one of the available gold layers.
b
Schematic top view of the
pentacene
resistor architecture which is built up with pentacene and two
gold contacts.
c
Schematic
top view
of the
linear-transistor
resistor architecture which is built up
in a rectangular way without finger structures
2.7.1.3 Transistor in Linear Regime
Other conducting or semiconducting materials than gold and pentacene are not sup-
plied in the applied organic electronics technology, yet there is another, probablymore
adequateway of making resistors. Transistors which are biasedwith a
V
SG
−
V
T
larger
than their
V
SD
are in the linear regime. Their resistance is derived from Eqs. (
2.5
)
and (
2.22
) and the result is given in Eq. (
2.23
):
1
R
SD
,
lin
=
(2.23)
W
μ
C
ox
×
L
(
V
SG
−
V
T
)
This resistance is given by the technological constants
μ
and
C
ox
, by the physical
sizes
W
and
L
, and by the gate overdrive
V
SG
−
V
T
that is typically large. With this
type of resistors a relatively accurate resistance is obtained since variations of
are
only in the range of a few percents up to in the worst case a few tens of percents.
Since the working region as well as the dimensions of the transistors in this section
are far from the more conventional transistor biasing (in saturation) and sizing which
are used for fitting the transistor model it is safer to measure a set of these resistors
μ
