Materials, Advanced Design
&
Manufacturing
93
2.5
Solid state electronics
Keywords
Organic, polymer, silicon, microelectromechanical
systems (MEMS), radio-frequency identification
(
RFID), metal oxide semiconductor field-effect
transistors (MOSFETs), thin film transistors (TFTs), 3G
neural networks, micropower SOI, high k dielectrics,
characterisation, metrology, modelling
Expertise
The University of Liverpool is involved in the development
of low-cost organic devices such as thin film transistors
(
TFT) and circuitry for use in a variety of applications
such as display, radio frequency (RF) and sensors. We
are also involved in the development of high performance
silicon structures and novel circuits for RF, micropower
and 3G neural network applications.
The University works on materials characterisation, both
electrical and optical, and also produce novel devices
through full design cycle, modelling, theory and
development. We have longstanding expertise in
semiconductor characterisation and device design,
theory and modelling using bespoke commercial tools.
We focus on the development of new designs and
processing concepts for organic-based circuitry for use
as functional blocks in applications such as sensors.
The novel designs adapt the material properties
associated with organic materials, which are not
applicable to conventional silicon designs. Organic
device models, also developed at the University are
used to accurately simulate the circuit performance.
Low-cost processes for development of the circuits are
optimised for enhanced performance.
Our expertise also spans the use and design of devices
for use in silicon VLSI and 3rd generation hardware
neural networks. Emphasis in the VLSI area is on the
use of newer materials and techniques in advanced
technologies for improving the performance of existing
logic families, and also in novel device and circuit cell
architectures for neural computing. Higher performance
at lower power consumption for bipolar transistors and
complementary metal-oxide-semiconductor (CMOS) is
a key factor for electronic circuits for mobile phones and
laptops, whereas a trade-off between parallelism and
speed is important for neural network hardware.
Liverpool has a lengthy track record of successful
research into the testing and reliability of gate dielectrics
for silicon-based electronics. There is considerable
activity around high-permittivity dielectrics for end-of-
roadmap application. The University also has excellent
atomic layer deposition (ALD) facilities. New work is
aimed at producing very high precision passive
components, particularly capacitors for medical,
RF and energy harvesting applications.
We also work on micropower analogue circuits for
medical and other uses. Further circuit work is
associated with neuron devices activity whereby
standard cell building blocks are under construction for
potential use in large, brain-inspired electronic systems.
Capabilities and facilities
The University offers basic test sample and device
fabrication facilities together with an extensive suite
of electrical and optical characterisation equipment.
These facilitate the evaluation of organic and inorganic
semiconductors and composites of the former with
conjugated polymers, small molecules and nanotubes.
The electrical test equipment can be configured for
automated stress measurements on devices such as
thin-film transistors and metal oxide semi-conductor
(
MOS) capacitors.
A comprehensive range of electrical and physical
characterisation tools are available:
•
Multi-frequency capacitance-voltage
•
Low current-voltage including temperature
dependence
•
Spectroellipsometry
•
X-ray spectroscopy (XPS)
•
Medium energy ion spectroscopy (MEIS)
•
X-ray diffraction (XRD)
•
High-resolution transmission electron
spectroscopy (XTEM).
Fabrication facilities
Clean room facilities allow the production of prototype
field effect transistor (FET) devices in polymers and
two-terminal test structures in silicon. We also offer
facilities for the fabrication of organic TFT devices,
diodes and capacitors which can be integrated with
antennas on to thin, flexible, transparent substrates.
