NMOS threshold voltage

[icx]

nmos threshold

for a nmos transistor ,if source is connected to ground,which one has the
largest threshold voltage?

a.connect substrate to -0.3v
b. connect substrate to 0v
c. connect substrate to 0.3v
d. connect substrate to 0.5v

 

[shadoweek]

usually, when the source potential is higher than the bulk potential, the threshold voltage of the NMOS increases. you didn't mention if the bulk is the substrate or not in the process you are using... it differs....so, check it first.... plus, read the process manual, you could have no choice in the substrate potential... sometimes, the process limits your choices