Hspice programming for nmos simulation

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sam139

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Hello guys,

I am a beginner with hspice and please help me with this problem. I want to simulate Ids vs.Vds for Vgs = 0, 0.2, 0.4 for a nMOS transistor in a 65 nm process with W/L = 120 nm/80 nm. The maximum value of V ds is 1.0V.
Kindly let me know how to go on with programing this problem.

Any help would be appreciated.
 

.include (library path)
Vdd1 vdd 0 dc 1v
Vds vd 0 dc 1v
Vgs vg 0 dc 0.4v
Mn1 vo vg vd vd nmos
.dc vds 0 1 0.1 sweep vgs 0 0.2 0.4
.ends
 

gs65, I wonder where you picked up these SPICE lines. And also, what you'll answer if someone asks why they are completely wrong?
Code: 
.include (library path)
Vdd1 vdd 0 dc 1v
Vds vd 0 dc 1v
Vgs vg 0 dc 0.4v
Mn1 vo vg vd vd nmos
.dc vds 0 1 0.1 sweep vgs 0 0.2 0.4
.ends
 

@fvm, there was some syntax error in my previous code. i have checked the output for the below.

Code: 
*nmos iv characteristics
*library path
.include C:\Users\Ananya\Desktop\h_spice\180micron.txt

***********component declearations******************
*voltage elements declarations

vds vd gnd dc 1.8
vgs vg gnd dc 1.0
vsb vb gnd dc 1.8
vss vs gnd dc 0

*m1-component declaration-user defined
*nmos-instantiation of model 	NMOS which is already present in the library

mm1 vd vg vs vb nmos w=2u l=0.18u
****************************************************

*dc_analysys


.dc vgs 0 1.8 0.001 sweep vgs 0 0.2 0.4

* for selecting the output current ids
.probe dc i(mm1)

.end
 
Last edited by a moderator:

The circuit looks better, but forward biasing the substrate with 1.8 V usually burns any real MOSFET. The substrate of a NMOS transistor has to be connected to the most negative node, in this case gnd.

You can watch the currents in your simulation,. there should be no substrate current.
 

Yes, it should. In CMOS IC technology, N and P substrates are "automatically" connected to VSS and VDD respectively.
 

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