of the reverse bias in nMOS.
In MOS Drain
does not have any structural difference with Source and when it comes to n
channel MOS are islets type n in structure (Body) type p. As a
result there is a pn junction between the p Body and the n Drain and similarly
the Source. In some
types of nMOS the Body is connected to a free terminal and if biased at a
potential more negative than the source then the VT of the
transistors increases, and vice versa. In other
types is connected internally to Source and both have a common terminal so VT
does not affected. This is the reason that this terminal is used exclusively
for Source to those types. pn junction
of Body – Drain normally is reversed bias and thus is not conductive. The nMOS used
in the specific application is this type.
of the reverse bias of the transistor when the output circuit is at logic 0, as
mentioned above, pn junction Body – Drain is forward biased and therefore
conductive. Furthermore the inducted channel is open due to gate bias. We can
simulate this connection as if we interchange the Source with the Drain and
connect the Body at positive potential. For all
these reasons, the transistor is at high conductivity state and the input
circuit is at logic 0 after the state being transferred through transistor.