Biomedical Engineering Reference
In-Depth Information
Figure 9.12
(A) Photographs of released arrays of organic CantiFETs (B) SEM
micrograph of the fabricated CantiFET device (C) Bottom and enlarged view of cantilever
portion of the CantiFET from SEM showing the inter digitated source drain electrode
coni guration (Type 1 & 3 CantiFET) (D) Top and enlarged view of cantilever portion of
the CantiFET from SEM [28].
9.3.2
Characterization of Organic CantiFET
h e organic CantiFETs were electrically characterized inside a shielded, vibra-
tion isolated probe station. h e electrical measurements were performed at
room temperature under ambient atmospheric conditions using semiconduc-
tor parameter analyzer. Output and transfer characteristics for these devices
were recorded. h e extracted saturation i eld ef ect mobility (μ) and threshold
voltage (V
TH
) were found to be 3.7 × 10
-4
cm
2
/Vs and -11.5 V respectively. h ese
integrated OTFTs exhibited low gate leakage and good switching characteris-
tics (Gate current density =1.2 × 10
-7
A/cm
2
@ V
GS
=-40V and I
ON
/I
OFF
= 2.2 ×
103). h e output characteristics of encapsulated Organic CantiFET exhibited
a linear increase in the drain current at low drain bias (Figure
9.13(b)). h is
is a clear indication of the existence of good ohmic contact at the interface of
source/drain electrodes and the organic semiconductor. At high drain biases,
proper saturation of drain current was also observed.
h e mechanical characterization of CantiFET devices were performed
by beam bending technique using a nanoindenter tool following the pro-
cedure explained in the previous section for nanocomposite microcantile-
vers. h e spring constant obtained using this method is 0.4 N/m[28].
In order to verify the suitability of CantiFET devices for biochemical
sensing applications, the fabricated devices were electromechanically char-
acterized to extract the surface stress sensitivity. h e CantiFET device was
