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isaacnewton
Joined: 13 May 2004
Posts: 155
Helped: 2
Location: Earth Village
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 24 Feb 2005 6:30 LAMBDA ? |
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Hi,
I have a question about Channel-length modulation parameter - lambda. I copied the following from:
www.mosis.org/cgi-bin/cgiwrap/umosis/swp/params/tsmc-025/t4cs_mm_non_epi-params.txt
Is the 'lambda' there channel-length modulation parameter? Thank you.
Copied from mosis.com
| Code: |
-------------------------------------------------------------------------------------
COMMENTS: Poly bias varies with design technology. To account for mask
bias use the appropriate value for the parameters XL and XW
in your SPICE model card.
Design Technology XL (um) XW (um)
----------------- ------- ------
SCN5M_DEEP (lambda=0.12) 0.00 -0.04
thick oxide, NMOS -0.01 -0.04
thick oxide, PMOS -0.06
SCN6M_SUBM (lambda=0.15) -0.06 0.00
thick oxide, NMOS -0.10 0.00
thick oxide, PMOS -0.15
-------------------------------------------------------------------------------------
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arunragavan
Joined: 01 Jul 2004
Posts: 487
Helped: 21
Location: India
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| 24 Feb 2005 7:40 Re: LAMBDA ? |
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did u check the velocity.. velocity saturation is inversely proportional to channel length modulation
take a look at this
h**p://www.inblue.com/gEDA/tools/acs/man/node74.html
with regards,
Last edited by arunragavan on 24 Feb 2005 17:17; edited 1 time in total |
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eda4you
Joined: 17 Sep 2002
Posts: 283
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| 24 Feb 2005 11:57 Re: LAMBDA ? |
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Hi!
lambda could also been the min. lenght (critical dimension). Some foundaries define their design rules not in absolute values (µm or nm), w but in multiple of λ.
I don't think that channel modulation is the lambda. The modulation varies in short channel devies over a wide range.
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skal81
Joined: 19 Jan 2005
Posts: 93
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| 24 Feb 2005 15:56 Re: LAMBDA ? |
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I don't think the lambda written there correponds to the channel modulation. It makes very little sense because:
1) This is a BSIM3 model. The lambda parameter is no longer used. (it's for MOS model 1 or model 2)
2) The part you've quote refer to the variations in W & L from drawn values.
In BSIM3 there is no explicit parameter for the modulation channel effect. However, you have the RDSW parameter that correspond to an equivalent drain source resistance. For more detail I suggest you refer to the BSIM3 manual.
Hope it helps
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isaacnewton
Joined: 13 May 2004
Posts: 155
Helped: 2
Location: Earth Village
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| 24 Feb 2005 17:32 Re: LAMBDA ? |
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| skal81 wrote: |
However, you have the RDSW parameter that correspond to an equivalent drain source resistance. For more detail I suggest you refer to the BSIM3 manual.
Hope it helps |
I checked the RDSW values on the MOSIS webpage.
www.mosis.org/cgi-bin/cgiwrap/umosis/swp/params/tsmc-025/t4cs_mm_non_epi-params.txt
The RDSW for NMOS is 200, for PMOS is about 1780. I looks like the values for RDSW - 'equivalent drain source resistance' are very small.
Thank you.
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skal81
Joined: 19 Jan 2005
Posts: 93
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| 24 Feb 2005 23:53 Re: LAMBDA ? |
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| Quote: |
| The RDSW for NMOS is 200, for PMOS is about 1780. I looks like the values for RDSW - 'equivalent drain source resistance' are very small. |
I don't remember the exact formula, but to get the drain-source resistance you have something like:
Rds = RDSW/(1e6*W).
The principle is that the small W the higher the resistance. However as I said it does not correpond to the channel modulation effect, but it's the parasitic resistance that appears in submicron.
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Analog_IC
Joined: 22 Jan 2005
Posts: 46
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| 25 Feb 2005 2:24 Re: LAMBDA ? |
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hello issac
http://www.mosis.org/Technical/Designsupport/mosis-design-example.html
if u read here 1. select a technology.
probably u will have answer.
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