how to vary atmospheric temperature in silvaco TCAD?

hello there!!
I'm trying to design a thermistor using silicon that can measure temperatures like 10k - 100k..
I've got all the structure and everything right, i've used 'Transport Equations' and 'Energy balance transport equations', so they are dependent on the lattice temperature, but i can't find a way to change temperature of the surrounding.
I'm new to silvaco TCAD, so if you would start with giving some basic ideas, that's be great!!
how to then actually plot the curve of voltage and temperature?
thanks in advance

---------- Post added at 12:27 ---------- Previous post was at 12:26 ----------

I'm using ATLAS, to simulate it...

well so i figured out that we can't vary the atmospheric temperature in atlas, so what is did is, I made one of the electrode i.e cathode the temperature varying heat source. I used 'thermal' as one of the models, so it had to be designed as a 3d model... well the modelling is done perfect, but i can't seem to figure out how to obtain the solution. i'm stuck up there... well so i'm going to paste the codes here... do give suggestions... thanks in advance

go atlas

mesh three.d

x.mesh loc=0.0 spac=20
x.mesh loc=254 spac=20

y.mesh loc=0.0 spac=10
y.mesh loc=150 spac=10

z.mesh loc=0.0 spac=20
z.mesh loc=500 spac=20

region num=1 material=silicon x.min=0 x.max=254 y.min=0 y.max=130 z.min=0 z.max=500
region num=2 material=gold x.min=102 x.max=152 y.min=130 y.max=150 z.min=150 z.max=350
region num=3 material=conductor x.min=0 x.max=254 y.min=0 y.max=10 z.min=0 z.max=500


electrode num=1 name=anode material=gold x.min=0 x.max=254 y.min=130 y.max=150 z.min=0.0 z.max=500
electrode num=2 name=cathode material=aluminium x.min=0 x.max=254 y.min=0 y.max=10 z.min=0 z.max=500

doping uniform conc=1e17 n.type x.min=0 x.max=254 y.min=10 y.max=130 z.min=0 z.max=500
doping uniform p.type conc=1e19 x.min=0 x.max=254 y.min=90 y.max=130 z.min=0 z.max=500

save outf=3ddiode.str
tonyplot3d 3ddiode.str -set 3ddiode.set

models srh conmob bgn auger fldmob hcte lat.temp thermal

#I've set the whole cathode electrode as my thermcontact
thermcontact num=1 material=aluminium x.min=0 x.max=254 y.min=0 y.max=10 z.min=0 z.max=500


material mat=silicon taurel.el=0.25e-12 taumob.el=0.25e-12 taurel.ho=0.25e-12 taumob.ho=0.25e-12

interface r1material=silicon r2material=gold
interface r1material=silicon r2material=aluminium

method block newton climit=1.e-5

#initial condition for solving
solve vanode=0

log outf=3d1.log master



# i don't which conditions to use to solve it.. so i've tried using these three individually, but did not work out...
solve vanode=0.0 name=anode vstep=0.2 vfinal=0.8
solve name=cathode t1=0 nstep=50 tempfinal=300
solve t1=0 power1=0.35 nstep=5 electrode=2 tempfinal=600 outfile=thermal_out0

save outf=3d2.str

tonyplot 3d1.log -set 3d1.set


extract name="max.volt" y.val from curve(v."anode", temp."cathode") where x.val=0.0

quit


i'm new to this stuffs, so even for my silly mistakes do tell me...