<s>
Drain-induced	B-Algorithm
barrier	I-Algorithm
lowering	I-Algorithm
(	O
DIBL	B-Algorithm
)	O
is	O
a	O
short-channel	O
effect	O
in	O
MOSFETs	B-Architecture
referring	O
originally	O
to	O
a	O
reduction	O
of	O
threshold	O
voltage	O
of	O
the	O
transistor	B-Application
at	O
higher	O
drain	O
voltages	O
.	O
</s>
<s>
In	O
a	O
classic	O
planar	O
field-effect	O
transistor	B-Application
with	O
a	O
long	O
channel	O
,	O
the	O
bottleneck	O
in	O
channel	O
formation	O
occurs	O
far	O
enough	O
from	O
the	O
drain	O
contact	O
that	O
it	O
is	O
electrostatically	O
shielded	O
from	O
the	O
drain	O
by	O
the	O
combination	O
of	O
the	O
substrate	O
and	O
gate	O
,	O
and	O
so	O
classically	O
the	O
threshold	O
voltage	O
was	O
independent	O
of	O
drain	O
voltage	O
.	O
</s>
<s>
In	O
short-channel	O
devices	O
this	O
is	O
no	O
longer	O
true	O
:	O
The	O
drain	O
is	O
close	O
enough	O
to	O
gate	O
the	O
channel	O
,	O
and	O
so	O
a	O
high	O
drain	O
voltage	O
can	O
open	O
the	O
bottleneck	O
and	O
turn	O
on	O
the	O
transistor	B-Application
prematurely	O
.	O
</s>
<s>
The	O
combined	O
charge	O
in	O
the	O
depletion	B-Algorithm
region	I-Algorithm
of	O
the	O
device	O
and	O
that	O
in	O
the	O
channel	O
of	O
the	O
device	O
is	O
balanced	O
by	O
three	O
electrode	O
charges	O
:	O
the	O
gate	O
,	O
the	O
source	O
and	O
the	O
drain	O
.	O
</s>
<s>
As	O
drain	O
voltage	O
is	O
increased	O
,	O
the	O
depletion	B-Algorithm
region	I-Algorithm
of	O
the	O
p-n	O
junction	O
between	O
the	O
drain	O
and	O
body	O
increases	O
in	O
size	O
and	O
extends	O
under	O
the	O
gate	O
,	O
so	O
the	O
drain	O
assumes	O
a	O
greater	O
portion	O
of	O
the	O
burden	O
of	O
balancing	O
depletion	B-Algorithm
region	I-Algorithm
charge	O
,	O
leaving	O
a	O
smaller	O
burden	O
for	O
the	O
gate	O
.	O
</s>
<s>
Barrier	O
lowering	O
increases	O
as	O
channel	O
length	O
is	O
reduced	O
,	O
even	O
at	O
zero	O
applied	O
drain	O
bias	O
,	O
because	O
the	O
source	O
and	O
drain	O
form	O
pn	O
junctions	O
with	O
the	O
body	O
,	O
and	O
so	O
have	O
associated	O
built-in	O
depletion	B-Algorithm
layers	I-Algorithm
associated	O
with	O
them	O
that	O
become	O
significant	O
partners	O
in	O
charge	O
balance	O
at	O
short	O
channel	O
lengths	O
,	O
even	O
with	O
no	O
reverse	O
bias	O
applied	O
to	O
increase	O
depletion	O
widths	O
.	O
</s>
<s>
The	O
term	O
DIBL	B-Algorithm
has	O
expanded	O
beyond	O
the	O
notion	O
of	O
simple	O
threshold	O
adjustment	O
,	O
however	O
,	O
and	O
refers	O
to	O
a	O
number	O
of	O
drain-voltage	O
effects	O
upon	O
MOSFET	B-Architecture
I-V	O
curves	O
that	O
go	O
beyond	O
description	O
in	O
terms	O
of	O
simple	O
threshold	O
voltage	O
changes	O
,	O
as	O
described	O
below	O
.	O
</s>
<s>
As	O
channel	O
length	O
is	O
reduced	O
,	O
the	O
effects	O
of	O
DIBL	B-Algorithm
in	O
the	O
subthreshold	O
region	O
(	O
weak	O
inversion	O
)	O
show	O
up	O
initially	O
as	O
a	O
simple	O
translation	O
of	O
the	O
subthreshold	O
current	O
vs.	O
gate	O
bias	O
curve	O
with	O
change	O
in	O
drain-voltage	O
,	O
which	O
can	O
be	O
modeled	O
as	O
a	O
simple	O
change	O
in	O
threshold	O
voltage	O
with	O
drain	O
bias	O
.	O
</s>
<s>
DIBL	B-Algorithm
also	O
affects	O
the	O
current	O
vs.	O
drain	O
bias	O
curve	O
in	O
the	O
active	O
mode	O
,	O
causing	O
the	O
current	O
to	O
increase	O
with	O
drain	O
bias	O
,	O
lowering	O
the	O
MOSFET	B-Architecture
output	O
resistance	O
.	O
</s>
<s>
This	O
increase	O
is	O
additional	O
to	O
the	O
normal	O
channel	B-Algorithm
length	I-Algorithm
modulation	I-Algorithm
effect	O
on	O
output	O
resistance	O
,	O
and	O
cannot	O
always	O
be	O
modeled	O
as	O
a	O
threshold	O
adjustment	O
.	O
</s>
<s>
In	O
practice	O
,	O
the	O
DIBL	B-Algorithm
can	O
be	O
calculated	O
as	O
follows	O
:	O
</s>
<s>
The	O
minus	O
in	O
the	O
front	O
of	O
the	O
formula	O
ensures	O
a	O
positive	O
DIBL	B-Algorithm
value	O
.	O
</s>
<s>
Typical	O
units	O
of	O
DIBL	B-Algorithm
are	O
mV/V	O
.	O
</s>
<s>
DIBL	B-Algorithm
can	O
reduce	O
the	O
device	O
operating	O
frequency	O
as	O
well	O
,	O
as	O
described	O
by	O
the	O
following	O
equation	O
:	O
</s>
