code:-
go atlas
mesh space.mult=1.0
#
x.mesh loc=0.00 spac=0.25
x.mesh loc=2.00 spac=0.25
x.mesh loc=3.00 spac=0.2
x.mesh loc=4.00 spac=0.2
#
y.mesh loc=0.00 spac=0.03
y.mesh loc=0.15 spac=0.005
y.mesh loc=0.20 spac=0.015
y.mesh loc=0.25 spac=0.01
y.mesh loc=0.50 spac=0.05
y.mesh loc=0.75 spac=0.01
y.mesh loc=0.90 spac=0.03
#
#
region num=1 material=GaAs y.min=0.75
region num=2 material=GaAs y.min=0.25 y.max=0.75
region num=3 material=AlGaAs y.max=0.0 x.comp=0.3 \
grad.34=0.15
region num=4 material=GaAs y.min=0.15 y.max=0.25
region num=5 material=SiO2 y.max=0.15 x.max=3.0
#
elec num=1 name=emitter x.min=3.0 x.max=4.0 y.min=0.0 y.max=0.0
elec num=2 name=base x.min=0.0 x.max=2.0 y.min=0.15 y.max=0.15
elec num=3 name=collector bot
#
doping uniform region=1 n.type conc=2.e17
doping uniform region=2 n.type conc=5.e16
doping uniform region=3 n.type conc=2.e17
doping uniform region=4 p.type conc=2.e18
#
material taun0=1.e-9 taup0=1.e-9
material material=AlGaAs mun=2200 mup=350
model srh fldmob print optr
model material=GaAs conmob evsatmod=1
#
solve init
save outf=hbt.str
tonyplot hbt.str
method gummel newton trap vsatmod.inc=0.01
solve
solve local vcollector=2.0
log outf=hbt.log
solve vbase=0.025
solve vbase=0.1
method newton autonr trap vsatmod.inc=0.01 itlim=50
solve vbase=0.2 vstep=0.1 name=base vfinal=1.4
solve vbase=1.45 vstep=0.025 name=base vfinal=1.5
tonyplot hbt.log
quit