PMOS vs NMOS size

[Gurjot Singh Bakhshi]

Someone told me in CMOS the size of the P-MOSFET is thrice the size of the NMOS.

is it so? why?

and what is thrice? the Lenght,Width or Area?

 

[Bob Myers]

"Gurjot Singh Bakhshi" <gurjotgurjot@yahoo.com> wrote in message
news:b45d3ae9.0407080258.7a63059@posting.google.com...

Someone told me in CMOS the size of the P-MOSFET is thrice the size of the
NMOS.

is it so? why?

It's due to the lower (poorer) mobility of charge carriers
in P-type material vs. N-type; N mobilities are generally
more than twice that of P.

and what is thrice? the Lenght,Width or Area?

There would be some impact in all areas, but generally
it would be the "width" - if by that we're talking about
the dimension primarily responsible for controlling the
per-unit-length resistance. (In other words, "width"
with respect to the direction of current flow, not
necessarily the shorter of two dimensions of a given
rectangle.)

Bob M.