Oct 15, 2012 #1 G glinsana Newbie level 2 Joined Oct 15, 2012 Messages 2 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,295 hi,guys i am really confused about Vth right now here is my story I have an pmos, it's model is from SMIC 0.13um and use BSIM3v3, Cadence ADE,spectre for simulation I choose to save DC operating point in order to save vth for my pmos but I found when L gets smaller, vth gets bigger. e.g.:L=130nm Vth=-430.9mV or so L=400nm Vth=-400mV How does this come out? can anyone help me ?;-)
hi,guys i am really confused about Vth right now here is my story I have an pmos, it's model is from SMIC 0.13um and use BSIM3v3, Cadence ADE,spectre for simulation I choose to save DC operating point in order to save vth for my pmos but I found when L gets smaller, vth gets bigger. e.g.:L=130nm Vth=-430.9mV or so L=400nm Vth=-400mV How does this come out? can anyone help me ?;-)
Oct 15, 2012 #2 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 glinsana said: ... I found when L gets smaller, vth gets bigger. L=130nm Vth=-430.9mV L=400nm Vth=-400mV Click to expand... |Vth| gets smaller!
glinsana said: ... I found when L gets smaller, vth gets bigger. L=130nm Vth=-430.9mV L=400nm Vth=-400mV Click to expand... |Vth| gets smaller!
Oct 15, 2012 #3 D dick_freebird Advanced Member level 7 Joined Mar 4, 2008 Messages 8,988 Helped 2,333 Reputation 4,683 Reaction score 2,520 Trophy points 1,393 Location USA Activity points 71,586 There are "short channel effects" and there are "reverse short channel effects" and the model params are only an attempt to fit the reality.
There are "short channel effects" and there are "reverse short channel effects" and the model params are only an attempt to fit the reality.
Oct 16, 2012 #4 G glinsana Newbie level 2 Joined Oct 15, 2012 Messages 2 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,295 erikl said: |Vth| gets smaller! Click to expand... Vth gets bigger…… by which i mean |Vth| - - - Updated - - - dick_freebird said: There are "short channel effects" and there are "reverse short channel effects" and the model params are only an attempt to fit the reality. Click to expand... I take them into consideration too. But the results i got yesterday by Id-Vgs DC sweep test brings a result that proves |Vth| should get smaller when L gets smaller.I think it is the right "short channel effect",isn't it?
erikl said: |Vth| gets smaller! Click to expand... Vth gets bigger…… by which i mean |Vth| - - - Updated - - - dick_freebird said: There are "short channel effects" and there are "reverse short channel effects" and the model params are only an attempt to fit the reality. Click to expand... I take them into consideration too. But the results i got yesterday by Id-Vgs DC sweep test brings a result that proves |Vth| should get smaller when L gets smaller.I think it is the right "short channel effect",isn't it?
Oct 16, 2012 #5 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 glinsana said: Vth gets bigger…… by which i mean |Vth| Click to expand... Yes, you're right, sorry!