In this video Les describes how the teaching chips provide a unique
resource to make the complexity of modern integrated circuits accessible
to novices in a unique and novel package.
Background:
I’m Les Haworth, a lecturer in the School of Engineering and Head of
Electronics and Electrical Engineering. I have a background in
semiconductor devices and fabrication having previously worked as a
process Engineer at the former Ferranti Electronics.
Projects I have worked on include cavity formation using ion
implantation as a means of impurity gettering in MOS transistors and
electrowetting over dielectric as a means of moving droplets of liquid
for lab on chip type applications. But the video is really about a
project intended to educate.
One of the features of microelectronics technology is its complexity.
When people hear of circuits containing millions of transistors, the
basic ideas can often become lost in the attempt to come to terms with
such complex circuits. The teaching chip project was devised to overcome
the sense of being overwhelmed by providing a set of integrated
circuits containing very simple devices and circuits such as resistors,
diodes and transistors that could be operated and measured
independently, but fabricated using technology that is not leading edge
so the devices are very large compared to modern state of the art
circuits. In this way students can appreciate how the simple elements
can be combined in increasingly large numbers to provide a complex
circuit. Much of electronics relies on the repeated and hierarchical
repetition of simple building blocks to achieve complex functionality,
and it is good, well structured design environments that permit
engineers to accomplish the highly creative designs that are used in
common devices such as mobile phones and tablet computers.
Chip 1 simply has resistors fabricated from either aluminium or
polycrystalline silicon. Chip 2 has only MOS transistors of different
sizes allowing simple logic gates or analogue circuits to be
constructed. Chip three has diodes and photodiodes while chip 4 is the
only chip with more complex circuitry including a ring oscillator that
allows an assessment of the delay introduced by a single logic gate. The
final novelty of these chips is that they are packaged using a
colourless transparent material that allows the devices to be easily
viewed using a normal lab microscope.
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