to go to our main microwaves history page
On this page we will collect
information on the evolution of MMICs. Why? Because we love this
stuff! Remember class, this is going to take some audience participation,
so send us some material!
Let's start with the world's
first MMIC, which was an amplifier. In 1975, a paper published by
Ray Pengelly and James Turner
entitled "Monolithic Broadband GaAs F.E.T. Amplifiers"
sealed their fate as the inventors of the MMIC. Working at Plessey,
their little single-stage amplifier provided 5 dB of gain at X-band
using 1 micron optically-written gates. They used computer optimization
to design their lumped element matching structures, which included
capacitors and inductors, but no DC blocking on the input/output.
Backside processing had not yet been worked out, so the FET's source
was grounded externally.
Let's let Ray Pengelly continue
"The picture you are
showing is not the actual first MMIC - that was a 2nd iteration
with higher gain and lower noise figure.
The CAD program was Compact
via GE satellite with home-grown lumped element models. The design
was done at Plessey Applied Research Labs, Roke Manor and fabricated
at Plessey Central Research Labs, Caswell. It was Comsat, so in
Washington DC I think -- too many years ago!?
I have some of the original
hand-drawn MMIC layouts dated March 3, 1975. These were then transferred
to Rubilith and then photo reduced and multi-upped to a mask --
GaAs substrates then were small, (1" or less) irregularly
shaped pieces so you didn't get many circuits per run. I remember
the celebrations in the clean room at Caswell when we got 6 circuits
all working at DC on one occasion!!