<s>
Monolithic	B-Algorithm
microwave	I-Algorithm
integrated	I-Algorithm
circuit	I-Algorithm
,	O
or	O
MMIC	B-Algorithm
(	O
sometimes	O
pronounced	O
"	O
mimic	O
"	O
)	O
,	O
is	O
a	O
type	O
of	O
integrated	O
circuit	O
(	O
IC	O
)	O
device	O
that	O
operates	O
at	O
microwave	O
frequencies	O
(	O
300MHz	O
to	O
300GHz	O
)	O
.	O
</s>
<s>
Inputs	O
and	O
outputs	O
on	O
MMIC	B-Algorithm
devices	O
are	O
frequently	O
matched	O
to	O
a	O
characteristic	O
impedance	O
of	O
50	O
ohms	O
.	O
</s>
<s>
This	O
makes	O
them	O
easier	O
to	O
use	O
,	O
as	O
cascading	O
of	O
MMICs	B-Algorithm
does	O
not	O
then	O
require	O
an	O
external	O
matching	O
network	O
.	O
</s>
<s>
MMICs	B-Algorithm
are	O
dimensionally	O
small	O
(	O
from	O
around	O
1mm²	O
to	O
10mm²	O
)	O
and	O
can	O
be	O
mass-produced	O
,	O
which	O
has	O
allowed	O
the	O
proliferation	O
of	O
high-frequency	O
devices	O
such	O
as	O
cellular	O
phones	O
.	O
</s>
<s>
MMICs	B-Algorithm
were	O
originally	O
fabricated	O
using	O
gallium	O
arsenide	O
(	O
GaAs	O
)	O
,	O
a	O
III-V	O
compound	O
semiconductor	O
.	O
</s>
<s>
It	O
has	O
two	O
fundamental	O
advantages	O
over	O
silicon	O
(	O
Si	O
)	O
,	O
the	O
traditional	O
material	O
for	O
IC	O
realisation	O
:	O
device	O
(	O
transistor	B-Application
)	O
speed	O
and	O
a	O
semi-insulating	O
substrate	B-Architecture
.	O
</s>
<s>
However	O
,	O
the	O
speed	O
of	O
Si-based	O
technologies	O
has	O
gradually	O
increased	O
as	O
transistor	B-Application
feature	O
sizes	O
have	O
reduced	O
,	O
and	O
MMICs	B-Algorithm
can	O
now	O
also	O
be	O
fabricated	O
in	O
Si	O
technology	O
.	O
</s>
<s>
Silicon	B-Architecture
wafer	I-Architecture
diameters	O
are	O
larger	O
(	O
typically	O
8	O
"	O
to	O
12	O
"	O
compared	O
with	O
4	O
"	O
to	O
8	O
"	O
for	O
GaAs	O
)	O
and	O
the	O
wafer	B-Architecture
costs	O
are	O
lower	O
,	O
contributing	O
to	O
a	O
less	O
expensive	O
IC	O
.	O
</s>
<s>
Originally	O
,	O
MMICs	B-Algorithm
used	O
metal-semiconductor	O
field-effect	O
transistors	B-Application
(	O
MESFETs	O
)	O
as	O
the	O
active	O
device	O
.	O
</s>
<s>
More	O
recently	O
high-electron-mobility	B-Algorithm
transistor	I-Algorithm
(	O
HEMTs	B-Algorithm
)	O
,	O
pseudomorphic	O
HEMTs	B-Algorithm
and	O
heterojunction	B-Algorithm
bipolar	I-Algorithm
transistors	I-Algorithm
have	O
become	O
common	O
.	O
</s>
<s>
However	O
,	O
they	O
also	O
tend	O
to	O
be	O
more	O
expensive	O
due	O
to	O
smaller	O
wafer	B-Architecture
sizes	O
and	O
increased	O
material	O
fragility	O
.	O
</s>
<s>
Silicon	O
germanium	O
(	O
SiGe	O
)	O
is	O
a	O
Si-based	O
compound	O
semiconductor	O
technology	O
offering	O
higher-speed	O
transistors	B-Application
than	O
conventional	O
Si	O
devices	O
but	O
with	O
similar	O
cost	O
advantages	O
.	O
</s>
<s>
Gallium	O
nitride	O
(	O
GaN	O
)	O
is	O
also	O
an	O
option	O
for	O
MMICs	B-Algorithm
.	O
</s>
<s>
Because	O
GaN	O
transistors	B-Application
can	O
operate	O
at	O
much	O
higher	O
temperatures	O
and	O
work	O
at	O
much	O
higher	O
voltages	O
than	O
GaAs	O
transistors	B-Application
,	O
they	O
make	O
ideal	O
power	O
amplifiers	O
at	O
microwave	O
frequencies	O
.	O
</s>
