T-Gate, Electron Temp & Lattice Temp (2D) - full deck
NOTE: The files "GaN Models Source File (2D)" and "TgateDimensions" must be saved and included in the same directory as this "T-Gate" file, or have paths pointing to these files, in order to run this T-Gate script. These two previously mentioned files are sourced within this T-Gate script to define material characteristics and to define the gate size in the grid. Links to these files are provided.
DevicePackage
pdbSetDouble Math iterLimit 800 pdbSetDouble Math rhsLimit 1.0e-15 pdbSetDouble Math updateLimit 1.0e-6 math device dim=2 col umf none scale
This command sources the "GaN Models source file". It is now set such that the "GaN Models source file" is in the same directory as this T-Gate script.
source GaN Models Source file (2D) - full deck #source GaN_ETemp
mater add name=Metal mater add name=OxPhase mater add name=Nitride
#Set up solution for displacement solution name = displacement add solve dim continuous negative solution name = Temp add solve solution name = ETemp add solve solution name = Jtherm add solve math diffuse dim=2 umf none col !scale
pdbSetBoolean GaN displacement Negative 1 pdbSetBoolean ReflectLeft displacement Negative 1 pdbSetDouble GaN displacement Abs.Error 1.0e-8 pdbSetDouble ReflectLeft displacement Abs.Error 1.0e-8
pdbSetBoolean AlGaN displacement Negative 1 pdbSetBoolean ReflectLeft displacement Negative 1 pdbSetDouble AlGaN displacement Abs.Error 1.0e-8 pdbSetDouble ReflectLeft displacement Abs.Error 1.0e-8
pdbSetBoolean Nitride displacement Negative 1 pdbSetBoolean ReflectLeft displacement Negative 1 pdbSetDouble Nitride displacement Abs.Error 1.0e-8 pdbSetDouble ReflectLeft displacement Abs.Error 1.0e-8
pdbSetBoolean OxPhase displacement Negative 1 pdbSetBoolean ReflectLeft displacement Negative 1 pdbSetDouble OxPhase displacement Abs.Error 1.0e-8 pdbSetDouble ReflectLeft displacement Abs.Error 1.0e-8
pdbSetBoolean ReflectRight displacement Negative 1 pdbSetDouble ReflectRight displacement Abs.Error 1.0e-8
#Fix base pdbSetBoolean ReflectBottom displacement Fixed 1 pdbSetString ReflectBottom displacement Equation "displacement" #Fix sides pdbSetBoolean ReflectLeft displacement Fixed 1 pdbSetString ReflectLeft displacement Equation "displacement"
pdbSetBoolean ReflectRight displacement Fixed 1 pdbSetString ReflectRight displacement Equation "displacement"
pdbSetString GaN displacement Equation "elastic(displacement)" pdbSetString AlGaN displacement Equation "elastic(displacement)-BodyStrain(0.004)+IPZ(DevPsi)" #pdbSetString AlGaN displacement Equation "elastic(displacement)+BodyStrain(0.004) pdbSetString OxPhase displacement Equation "elastic(displacement)" pdbSetString Nitride displacement Equation "elastic(displacement)+BodyStrain(0.00005)"
This command sources the "TgateDimensions" file. It is now set such that the "TgateDimensions" file is in the same directory as this T-Gate script. The AlGaN is now set to a 25nm thickness and gate length at the bottom is 0.3um.
source T-Gate Dimensions file (2D) - full deck
These lines create the device structure and define the grid sizing:
line x loc=-0.2 spac=0.01 tag=Gwt line x loc=-0.1 spac=0.01 tag=Gwb line x loc=-0.005 spac=0.001 tag=Ox line x loc=0.0 spac=0.001 tag=AlGaNTop line x loc=$Althick spac=0.005 tag=AlGaNBottom line x loc=1.0 spac=0.1 tag=BBottom
line y loc=-1.0 spac=0.05 tag=Left line y loc=$Gtl spac=0.02 tag=sidewL line y loc=$Gbl spac=0.02 tag=sidenL line y loc=$Gbr spac=0.02 tag=sidenR line y loc=$Gtr spac=0.02 tag=sidewR line y loc=1.0 spac=0.05 tag=Right
#Bulk region GaN xlo=AlGaNBottom xhi=BBottom ylo=Left yhi=Right
#AlGaN under gate region AlGaN xlo=AlGaNTop xhi=AlGaNBottom ylo=Left yhi=Right #Metal alloy for T-gate region Metal xlo=Gwt xhi=Gwb ylo=sidewL yhi=sidewR region Metal xlo=Gwb xhi=Ox ylo=sidenL yhi=sidenR
#Nitride cap layer region Nitride xlo=Gwt xhi=Gwb ylo=Left yhi=sidewL region Nitride xlo=Gwt xhi=Gwb ylo=sidewR yhi=Right region Nitride xlo=Gwb xhi=Ox ylo=Left yhi=sidenL region Nitride xlo=Gwb xhi=Ox ylo=sidenR yhi=Right
#Created Oxide layer region OxPhase xlo=Ox xhi=AlGaNTop ylo=Left yhi=Right
init quad
#Contacts
contact name=G Metal xlo=-0.195 xhi=-0.002 ylo=[expr {$Gtl-$buf}] yhi=[expr {$Gtr+$buf}] add depth=1.0 width=1.0
contact name=B GaN xlo=0.9 xhi=1.1 ylo=-1.0 yhi=1.0 add depth=1.0 width=1.0
contact name=S AlGaN ylo=-1.0 yhi=-0.9 xlo=-0.7 xhi=0.0005 add depth=1.0 width=1.0
contact name=D AlGaN ylo=0.9 yhi=1.0 xlo=-0.7 xhi=0.0005 add depth=1.0 width=1.0
contact name=G current=(Hole_AlGaN-Elec_AlGaN) voltage supply=0.0
contact name=B current=(Hole_GaN-Elec_GaN) voltage supply=0.0
contact name=D current=(Hole_GaN-Elec_GaN) voltage supply=0.0
contact name=S current=(Hole_GaN-Elec_GaN) voltage supply=0.0
#doping definition-will use method from pfmos_qf deck for simplicity
#GaN Doping-from Dessis file from Heller-acceptor-p-type
sel z=-6.5e16*Mater(GaN) name=GaN_Doping
#AlGaN Doping-from Dessis file from Heller-he puts equivalent donor and acceptor doping in region to signify traps
sel z=1e12 name=AlGaN_Doping
#sel z=1e12*Mater(OxPhase) name=OxPhase_Doping
#sel z=1e20*Mater(Metal)*(x>=-0.2)*(x<=-0.002)*(y>$Gtl)*(y<$Gtr) name=Metal_Doping
sel z=1e20*(x>=-0.2)*(x<=-0.002)*(y>$Gtl)*(y<$Gtr) name=Metal_Doping
#Source and Drain contact doping-from contact to 2DEG like Heller-just to make contacts ohmic
sel z=(1e19*(y>0.75)+(y<=0.75)*1.0e19*exp(-(y-0.75)*(y-0.75)/(0.75*0.02*0.02)))*(exp(-(x*x)/(2.0*0.03*0.03)))*(x>=0.0) name=Drain_Doping
sel z=(1e19*(y<-0.75)+(y>=-0.75)*1.0e19*exp(-(y+0.75)*(y+0.75)/(0.75*0.02*0.02)))*(exp(-(x*x)/(2.0*0.03*0.03)))*(x>=0.0) name=Source_Doping
#Total doping #sel z=GaN_Doping+AlGaN_Doping+Drain_Doping+Source_Doping+Metal_Doping+OxPhase_Doping name=Doping sel z=GaN_Doping+AlGaN_Doping+Drain_Doping+Source_Doping+Metal_Doping name=Doping sel z=0.26 name=AlN_Ratio
These procedures set up the options to plot the entire device, "Plot", or just the gate area, "Plotsmall":
proc Plot {} {
plot.2d bound
plot.2d contact=G !cle
plot.2d contact=B !cle
plot.2d contact=S !cle
plot.2d contact=D !cle
plot.2d contact=F1 !cle
plot.2d contact=F2 !cle
}
proc Plotsmall {} {
plot.2d bound min = {-2e-5 -4e-5} max = {1.5e-5 4e-5}
plot.2d contact=G !cle
}
proc Plotasy {} {
plot.2d bound min = {-2e-5 -6.5e-5} max = {1.5e-5 1.5e-5}
plot.2d contact=G !cle
}
Initialize
device init
These set the initial Gate, Source and Drain biases (Vgs,Vss avd Vdd). The gate voltage is set to -5V which puts the device in the OFF state:
#set Vgs -5.0 set Vgs -1.0 set Vdd 0.0 set Vss 0.0 set Vbb 0.0
This line creates the window in which the IV curve will be plotted:
set WinA [CreateGraphWindow]
This loop steps the drain voltage up from 0 to 15V in intervals of 0.4V:
for {set Vdd 0.00} {$Vdd<15.4} {set Vdd [expr $Vdd+0.4]} {
contact name=D supply=$Vdd contact name=G supply=$Vgs contact name=S supply=$Vss contact name=B supply=$Vbb
proc Templots {} {
sel z=ETemp
plot.1d x.v=0.026 lab=ETemp
sel z=Temp
plot.1d x.v=0.026 lab=Temp !cle
#sel z=Elec
#plot.1d x.v=0.026 lab=Elec !cle
}
Templots
sel z= {(energy<=VA)
? (2*sqrt((2*0.2*9.1e-31)/(1.054e-34*1.054e-34))*sqrt(abs(VA-energy)*1.6e-19)*0.025e-6)*Mater(AlGaN)
: (0*Mater(AlGaN))} name=gbox
sel z=(1-(energy/(1.5-G)))*(1-(energy/(1.5-G)))*(1-(energy/(1.5-G))) name=INS
sel z=sqrt(INS)*Mater(AlGaN) name=tri3
Note:1e4 factor to convert from cm to m
sel z=0.66*sqrt((2*$Mestar*(1.5-G)*(1.5-G)*(1.5-G)*$q)/(1e4*alph*alph*1.054e-34*1.054e-34))*Mater(AlGaN) name=front sel z=front*tri3 name=gtri sel z=(gbox+gtri) name=gtotal
Note: 1e2 factor to convert from m/s to cm/s
sel z=exp(-gtotal) name=TransProb sel z=Elec set channel [interpolate GaN x=0.026 y=0.0625] sel z=1*$channel name=channelElec sel z=$q*$Vr*1e2*channelElec*TransProb name=Jtunnel
device
This plots the IV curve in the created window named "WinA":
set cur [expr -1e3*([contact name=D sol=Qfn flux] - [contact name=D sol=Qfp flux])] AddtoLine $WinA IV.$Vgs $Vdd $cur }
This command saves the structure and all variables which were solved for within the device. This file can be read back into FLOOXS, or can be read by a number of plotting programs eg TecPlot, PL Plot etc:
struct outf=ETempandTempVdd15