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BSIM4 MOSFET Model - RF Cafe Forums
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Quasar
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Post subject: BSIM4 MOSFET Model
Posted: Wed Jul 11, 2007 9:14 am
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Joined: Fri Aug 11, 2006
6:07 am Posts: 8 |
I'm trying to simulate a circuit containing a MOSFET
at a frequency of around 2GHz. The problem I'm facing
is that I can't seem to find a MOSFET that operates
in that frequency range (It needs to be a switching
MOSFET, which means the transistor operating frequency
should be around 20GHz for it to have a small enough
capacitance). I tried creating my own BSIM4 MOSFET
model, but the problem is that I'm not sure about
the values of the model parameters for it to be
physically realizable. Does anyone know of any place
where I can get detailed actual MOSFET model parameters
for high frequencies?
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jaslovkel |
Post subject:
Posted: Wed Jul 11, 2007 10:50 am
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Captain |
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Joined: Tue Jun 26, 2007
10:27 am Posts: 23 Location: Dallas, TX
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Hi Quasar, Depending on what type of MOSFET
you are needing and what your voltage levels are
will determine what kind of model parameters you
will be needing. For instance, if it is for large
voltages (>5 V) you will be needing a different
type of MOS with different parameters than one which
is less than 5 V. I don't know much about
higher voltage FETs, but for <5 V applications
an okay place to start is through the MOSIS web
site (www.mosis.org).
They keep a detailed list of SPICE parameters for
different size technologies (from 1.2um CMOS down
to 90nm) with different runs so that you can see
the process variations. As far as needing an ft
of greater than 20 GHz, you will need to use at
least 0.35um CMOS. Even then, it may be pushing
the limits. If you can't find the information
you need on the MOSIS site, you can always check
foundry web sites. Sometimes they post their SPICE
parameters there for older processes and you can
see if they are in the ballpark that you are in.
Hope this helps. -J
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Quasar |
Post subject:
Posted: Wed Jul 11, 2007 12:49 pm
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Joined: Fri Aug 11, 2006
6:07 am Posts: 8 |
Well, fortunately I don't need a high voltage MOSFET.
I did check out the MOSIS website and they do have
good details but the problem is that there are certain
parameters of the BSIM3 model that are not mentioned.
I think that's due to the fact that they test wafers,
not transistors. Information such as the contact
resistance of the gate, drain, and source, the width
and length of the channel, the area and perimeter
of the drain, and the source. All of these and some
more are critical for the design and are not mentioned.
So I ended up getting weird results on the simulator.
I guess I'll have to try to find a way to guess
these values, and I'll try using the 0.25um or the
0.18um CMOS. Thank you for your help.
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Posted 11/12/2012
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