<s>
The	O
metal	O
–	O
nitride	O
–	O
oxide	O
–	O
semiconductor	O
or	O
metal	O
–	O
nitride	O
–	O
oxide	O
–	O
silicon	O
(	O
MNOS	O
)	O
transistor	O
is	O
a	O
type	O
of	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
in	O
which	O
the	O
oxide	O
layer	O
is	O
replaced	O
by	O
a	O
double	O
layer	O
of	O
nitride	O
and	O
oxide	O
.	O
</s>
<s>
It	O
is	O
an	O
alternative	O
and	O
supplement	O
to	O
the	O
existing	O
standard	O
MOS	B-Architecture
technology	I-Architecture
,	O
wherein	O
the	O
insulation	O
employed	O
is	O
a	O
nitride-oxide	O
layer	O
.	O
</s>
<s>
It	O
is	O
used	O
in	O
non-volatile	B-General_Concept
computer	B-General_Concept
memory	I-General_Concept
.	O
</s>
<s>
The	O
original	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
or	O
MOS	B-Architecture
transistor	I-Architecture
)	O
was	O
invented	O
by	O
Egyptian	O
engineer	O
Mohamed	O
M	O
.	O
Atalla	O
and	O
Korean	O
engineer	O
Dawon	O
Kahng	O
at	O
Bell	O
Labs	O
in	O
1959	O
,	O
and	O
demonstrated	O
in	O
1960	O
.	O
</s>
<s>
Kahng	O
went	O
on	O
to	O
invent	O
the	O
floating-gate	B-Algorithm
MOSFET	I-Algorithm
with	O
Simon	O
Min	O
Sze	O
at	O
Bell	O
Labs	O
,	O
and	O
they	O
proposed	O
its	O
use	O
as	O
a	O
floating-gate	B-Algorithm
(	O
FG	O
)	O
memory	B-Algorithm
cell	I-Algorithm
,	O
in	O
1967	O
.	O
</s>
<s>
This	O
was	O
the	O
first	O
form	O
of	O
non-volatile	B-General_Concept
memory	I-General_Concept
based	O
on	O
the	O
injection	O
and	O
storage	O
of	O
charges	O
in	O
a	O
floating-gate	B-Algorithm
MOSFET	I-Algorithm
,	O
which	O
later	O
became	O
the	O
basis	O
for	O
EPROM	B-General_Concept
(	O
erasable	O
PROM	B-General_Concept
)	O
,	O
EEPROM	B-General_Concept
(	O
electrically	O
erasable	O
PROM	B-General_Concept
)	O
and	O
flash	B-Device
memory	I-Device
technologies	O
.	O
</s>
<s>
Richard	O
Wegener	O
invented	O
the	O
metal	O
–	O
nitride	O
–	O
oxide	O
–	O
semiconductor	O
(	O
MNOS	O
)	O
transistor	O
,	O
a	O
type	O
of	O
MOSFET	B-Architecture
in	O
which	O
the	O
oxide	O
layer	O
is	O
replaced	O
by	O
a	O
double	O
layer	O
of	O
nitride	O
and	O
oxide	O
.	O
</s>
<s>
Nitride	O
was	O
used	O
as	O
a	O
trapping	O
layer	O
instead	O
of	O
a	O
floating	B-Algorithm
gate	I-Algorithm
,	O
but	O
its	O
use	O
was	O
limited	O
as	O
it	O
was	O
considered	O
inferior	O
to	O
a	O
floating	B-Algorithm
gate	I-Algorithm
.	O
</s>
<s>
Charge	B-Algorithm
trap	I-Algorithm
(	O
CT	O
)	O
memory	O
was	O
introduced	O
with	O
MNOS	O
devices	O
in	O
the	O
late	O
1960s	O
.	O
</s>
<s>
It	O
had	O
a	O
device	O
structure	O
and	O
operating	O
principles	O
similar	O
to	O
floating-gate	B-Algorithm
(	O
FG	O
)	O
memory	O
,	O
but	O
the	O
main	O
difference	O
is	O
that	O
the	O
charges	O
are	O
stored	O
in	O
a	O
conducting	O
material	O
(	O
typically	O
a	O
doped	O
polysilicon	O
layer	O
)	O
in	O
FG	O
memory	O
,	O
whereas	O
CT	O
memory	O
stored	O
charges	O
in	O
localized	O
traps	O
within	O
a	O
dielectric	O
layer	O
(	O
typically	O
made	O
of	O
silicon	O
nitride	O
)	O
.	O
</s>
