Help simulate inverter.

hspice error effective channel length

I tried to simulate an inveter, but got some problems:
BSIM3 Fatal **error** Effective channel length <= 0
Device: W = -9.99973e-09, L = -1.99998e-08
I am using level 49 model parameters. Anyone have idea how to fix it?
-----MY code----------------
.option scale=1u accurate post probe
.lib 'tsmc18dP' PMOS
.lib 'tsmc18dN' NMOS
vdd vdd! 0 1.2
vgnd gnd! 0 0
vin in 0 pwl 0 0 1ns 0 1.2ns 1.2 2ns 1.2
MN0 out in gnd! gnd! TSMC18dN W=270n L=180.0n M=1
MP0 out in vdd! vdd! TSMC18dP W=270n L=180.0n M=1
.tran 0.01ns 2ns
.probe v(in) v(out)
.end
------Hspice Output file with errors----------
*warning** both nodes of source 0:vgnd
are connected together

**warning** mosfet device 0:mmp0 cdsat is too small at temperature 25.000
value= 1.23453E-37,cdsat reset to epsmin

**warning** mosfet device 0:mmp0 cssat is too small at temperature 25.000
value= 1.23453E-37,cssat reset to epsmin

BSIM3 Fatal **error** Effective channel length <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel length <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel length for C-V <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width for C-V <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

**warning** mosfet device 0:mmn1 cdsat is too small at temperature 25.000
value= 1.23453E-37,cdsat reset to epsmin

**warning** mosfet device 0:mmn1 cssat is too small at temperature 25.000
value= 1.23453E-37,cssat reset to epsmin

BSIM3 Fatal **error** Effective channel length <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel length <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel length for C-V <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

BSIM3 Fatal **error** Effective channel width for C-V <= 0
Device: W = -9.99973e-09, L = -1.99998e-08

***** job aborted
1 ****** HSPICE -- V-2004.03 (20040116) 16:51:52 11/08/2005 solaris
******
************************************************************************
****** job statistics summary tnom= 25.000 temp= 25.000

bsim3 fatal error

Try to remove scale=1u from options.

effective channel length <= 0

You're getting this error because the channel length should be at least 2 times the minimum feature size. For the MOS transistor, the Length L is differenct from the actual channel lenght. This actual channel length is known as Effective Channel length and is given by

\[Leff = Ldrawn - 2Ld\]

where Ldrawn is the total length
and Ld is the lateral difusion.

So, in your case you've taken the L-0.18µ (180nm). Check the spice model file for the value of Ld (lateral diffusion). Therefore the effective length of your transistor is lesser than than the minimum feature size. This is why you get the error.

It is a good design practice to keep the length at least 2 times the minimum feature size to avoid such problems.

To solve the problem, increase the channel length and witdhs. Then run the simulation. It will work without any errors.

bsim3 effective channel length

Try this CMOS library.

effective channel length hspice error

In my opinion,if the model gives the value of lmin (some models do not have the LD parameter), you should make the L>lmin.
Else, you should use the formula Leff=Ldraw-2LD, to make your Leff>0.

"BSIM3 Fatal **error** Effective channel width <= 0"

I think it is clear that your library has Ld, therefore if you set the L as the minimum, the simulation will get this error.