I am trying to get a device's characteristics under different temperatures ranging from 70 K to 300K, but it is having convergence errors below 150K. Also, I am trying to do it in default Drift-Diffusion model, instead of using Thermodynamic or Hydrodynamic. Can I get results down to 70K while using Drift-Diffusion?

Given below is the code. Also, if I use "Temperature" keyword in "Coupled", results show reduced mobility than the expected values, so I didn't use it. Commented lines are not active, Channel length is 12 nm which are of SiliconGermanium.

Electrode{

{ Name = "Drain" Voltage=0 }

{ Name = "Gate" Voltage=0 }

{ Name = "Source" Voltage=0 }

}

Thermode{

{ Name = "Drain" Temperature=@temp@ SurfaceResistance=1e-4}

{ Name = "Gate" Temperature=@temp@ SurfaceResistance=1e-4}

{ Name = "Source" Temperature=@temp@ SurfaceResistance=1e-4}

}

File {

Grid = "n1_msh.tdr"

Plot = "@tdrdat@"

Current = "@plot@"

Output = "@log@"

Parameter = "sdevice.par"

}

Physics(Material = "Metal"){MetalWorkFunction (WorkFunction = 4.49)}

Physics(MaterialInterface="SiliconGermanium/Tungsten") { MSPeltierHeat }

Physics {

MoleFraction(RegionName = ["R.NmosDrain" "R.NmosSource" "R.NmosChannel1" "R.NmosChannel2" "R.NmosChannel3"]

xFraction=@mf@

)

}

Physics {

*Hydrodynamic

RecGenHeat

AnalyticTEP

Temperature=@temp@

Fermi

EffectiveIntrinsicDensity( BandGapNarrowing(OldSlotboom) )

*eQuantumPotential

*hQuantumPotential

Mobility(

*DopingDep

*eHighFieldsaturation

*Enormal(Lombardi)

*BalMob(Lch=12.0 Fermi Frensley TempDep)

)

*Recombination(

*SRH( DopingDep TempDependence ))

}

Math {

Digits=6

-CheckUndefinedModels

*DensLowLimit=-100 -ExtendedPrecision

Extrapolate

*Avalderivatives

Iterations= 100

Notdamped= 100

Method= Blocked

SubMethod= Pardiso

ErRef(Electron)=1e8

ErRef(Hole)=1e8

Transient= BE

RefDens_eGradQuasiFermi_ElectricField= 1e16

RefDens_hGradQuasiFermi_ElectricField= 1e16

-PlotLoadable

*RefDens_QuantumPotential= 1e9

DirectQuantumCorrection

NumberOfThreads=32

}

Solve {

*Coupled(Iterations=100 ){Poisson eQuantumPotential hQuantumPotential}

*Coupled(Iterations=100 ){Poisson Electron Hole}

Coupled(Iterations=100 ){Poisson Electron Hole}

NewCurrentPrefix="IdVds_onlynmos_temp=@temp@_mf=@mf@"

Quasistationary(

InitialStep=1e-4 MinStep=1e-6 MaxStep=2

Goal{ Name="Drain" Voltage= 0.6 }

) { Coupled {Poisson Electron Hole}

CurrentPlot(Time=(Range=(0 1) Intervals=20))

}

NewCurrentPrefix="IdVgs_onlynmos_temp=@temp@_mf=@mf@"

Quasistationary(

InitialStep=1e-4 MinStep=1e-6 MaxStep=2

Goal{ Name="Gate" Voltage= 0.8}

) { Coupled {Poisson Electron Hole}

CurrentPlot(Time=(Range=(0 1) Intervals=20))

}

}

Plot{

eDensity hDensity

BandGap BandGapNarrowing Affinity ConductionBand ValenceBand eMobility hMobility

eQuantumPotential

}