Pulse voltage problem in Hspice

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discover93

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I am new to the whole subject so please bear with me. I write a simple problem for nand gate in Hspice and as input I used two pulse voltage. However the wave I get is not a pulse. Here is my code and waves:

Code: 
# NAND2 

.include ./22nm_lp.pm.txt

M1 c a 1 1 pmos l=22n w=44n *Ap
M2 c b 1 1 pmos l=22n w=44n *Bp 

M3 c a 2 2 nmos l=22n w=22n *An
M4 2 b 0 0 nmos l=22n w=22n *Bn

vdd 1 0 dc 0.95V
vb b 0 pulse 0.95 0 0 5n 5p 95p 200p 
va a 0 pulse 0.95 0 0 5p 5p 95p 200p 

.option post accurate nomod
.MEASURE TRAN delay TRIG V(b) VAL=0.475  RISE=1
+                   TARG V(c) VAL=0.475  FALL=1
.tran 200p 1000p

.end



Can anyone please explain what's going on?
 

You get out what you put in. Why did you set vb rise time to 5 ns?

Apart from this point, the output voltage suggests that the transistor parameters aren't suited for the 0.95V operation.

If the circuit is somehow related to IC design, we would expect all substrates tied to VDD and GND, not floating like M3.
 

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