<s>
Silicon	B-Algorithm
on	I-Algorithm
sapphire	I-Algorithm
(	O
SOS	O
)	O
is	O
a	O
hetero-epitaxial	O
process	O
for	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
(	O
MOS	O
)	O
integrated	O
circuit	O
(	O
IC	O
)	O
manufacturing	B-Architecture
that	O
consists	O
of	O
a	O
thin	O
layer	O
(	O
typically	O
thinner	O
than	O
0.6µm	O
)	O
of	O
silicon	O
grown	O
on	O
a	O
sapphire	B-Application
(	O
Al2O3	O
)	O
wafer	B-Architecture
.	O
</s>
<s>
SOS	O
is	O
part	O
of	O
the	O
silicon-on-insulator	B-Algorithm
(	O
SOI	O
)	O
family	O
of	O
CMOS	B-Device
(	O
complementary	O
MOS	O
)	O
technologies	O
.	O
</s>
<s>
Typically	O
,	O
high-purity	O
artificially	O
grown	O
sapphire	B-Application
crystals	O
are	O
used	O
.	O
</s>
<s>
The	O
silicon	O
is	O
usually	O
deposited	O
by	O
the	O
decomposition	O
of	O
silane	O
gas	O
(	O
SiH4	O
)	O
on	O
heated	O
sapphire	B-Application
substrates	B-Architecture
.	O
</s>
<s>
The	O
advantage	O
of	O
sapphire	B-Application
is	O
that	O
it	O
is	O
an	O
excellent	O
electrical	O
insulator	O
,	O
preventing	O
stray	O
currents	O
caused	O
by	O
radiation	O
from	O
spreading	O
to	O
nearby	O
circuit	O
elements	O
.	O
</s>
<s>
SOS	O
faced	O
early	O
challenges	O
in	O
commercial	O
manufacturing	B-Architecture
because	O
of	O
difficulties	O
in	O
fabricating	O
the	O
very	O
small	O
transistors	B-Application
used	O
in	O
modern	O
high-density	O
applications	O
.	O
</s>
<s>
This	O
is	O
because	O
the	O
SOS	O
process	O
results	O
in	O
the	O
formation	O
of	O
dislocations	O
,	O
twinning	O
and	O
stacking	O
faults	O
from	O
crystal	O
lattice	O
disparities	O
between	O
the	O
sapphire	B-Application
and	O
silicon	O
.	O
</s>
<s>
Additionally	O
,	O
there	O
is	O
some	O
aluminum	O
,	O
a	O
p-type	O
dopant	O
,	O
contamination	O
from	O
the	O
substrate	B-Architecture
in	O
the	O
silicon	O
closest	O
to	O
the	O
interface	O
.	O
</s>
<s>
In	O
1963	O
,	O
Harold	O
M	O
.	O
Manasevit	O
was	O
the	O
first	O
to	O
document	O
epitaxial	O
growth	O
of	O
silicon	B-Algorithm
on	I-Algorithm
sapphire	I-Algorithm
while	O
working	O
at	O
the	O
Autonetics	O
division	O
of	O
North	O
American	O
Aviation	O
(	O
now	O
Boeing	O
)	O
.	O
</s>
<s>
Robinson	O
at	O
RCA	O
Laboratories	O
fabricated	B-Architecture
a	O
MOSFET	B-Architecture
(	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
field-effect	I-Architecture
transistor	I-Architecture
)	O
using	O
the	O
silicon-on-sapphire	B-Algorithm
process	O
.	O
</s>
<s>
Silicon	B-Algorithm
on	I-Algorithm
sapphire	I-Algorithm
pressure	O
transducer	O
,	O
pressure	O
transmitter	O
and	O
temperature	O
sensor	O
diaphragms	O
have	O
been	O
manufactured	O
utilizing	O
a	O
patented	O
process	O
by	O
since	O
1985	O
.	O
</s>
<s>
ESI	O
Technology	O
Ltd	O
.	O
in	O
the	O
UK	O
have	O
developed	O
a	O
wide	O
range	O
of	O
pressure	O
transducers	O
and	O
pressure	O
transmitters	O
that	O
benefit	O
from	O
the	O
outstanding	O
features	O
of	O
silicon	B-Algorithm
on	I-Algorithm
sapphire	I-Algorithm
.	O
</s>
<s>
Peregrine	O
Semiconductor	O
has	O
used	O
SOS	O
technology	O
to	O
develop	O
RF	B-Application
integrated	I-Application
circuits	I-Application
(	O
RFICs	O
)	O
including	O
RF	B-Algorithm
switches	I-Algorithm
,	O
digital	O
step	O
attenuators	O
(	O
DSAs	O
)	O
,	O
phase	O
locked-loop	O
(	O
PLL	O
)	O
frequency	O
synthesizers	O
,	O
prescalers	O
,	O
mixers/upconverters	O
,	O
and	O
variable-gain	O
amplifiers	O
.	O
</s>
<s>
Hewlett-Packard	O
used	O
SOS	O
in	O
some	O
of	O
their	O
CPU	B-Device
designs	O
,	O
particularly	O
in	O
the	O
HP	B-Device
3000	I-Device
line	O
of	O
computers	O
.	O
</s>
<s>
The	O
application	O
of	O
epitaxial	O
growth	O
of	O
silicon	B-Algorithm
on	I-Algorithm
sapphire	I-Algorithm
substrates	B-Architecture
for	O
fabricating	O
MOS	O
devices	O
involves	O
a	O
silicon	O
purification	O
process	O
that	O
mitigates	O
crystal	O
defects	O
which	O
result	O
from	O
a	O
mismatch	O
between	O
sapphire	B-Application
and	O
silicon	O
lattices	O
.	O
</s>
<s>
For	O
example	O
,	O
Peregrine	O
Semiconductor	O
's	O
SP4T	O
switch	O
is	O
formed	O
on	O
an	O
SOS	O
substrate	B-Architecture
where	O
the	O
final	O
thickness	O
of	O
silicon	O
is	O
approximately	O
95nm	O
.	O
</s>
