title 'GaN HEMT Double 1um Gate'

Coordinates
  cartesian3
variables
    Temp !(threshold=0.1)

select initgridlimit=0 smoothinit=off

definitions
k          { thermal conductivity -- values supplied later }
kgan=0.00021 {hexagonal GaN, W/um-K}
ksic=0.00049 {6H-SiC}
kau=0.000381 {Gold }
kcu=0.000401 {Cu}
kair=0.0000000257
Q          { Thermal source }
h=3e-11   {Heat transfer coefficient, here 30 W/m2-K = 30*10-12 W/um2-K}
PackageX=5715
PackageY=8660
SubstrateX=487.5
SubstrateY=1500
ChannelX=17.75
ChannelY=80
GateX1=15
GateX2=16
GateY=80

{Rho
RhoSic=3.211e-9 {g/um^3}
RhoCu=8.94e-9
RhoAu=19.30E-9
RhoGaN=6.1e-9
Cp
CpSic=1.09 {J/molK}
CpGaN=35.3 {*can be temperature dependent Cp=32.960+0.162*10^-1*Temp+2360170T^-2-775370000T^-3  Tomaskiewicz et al. "Heat Capacity of GaN" Journal of Thermal analysis and colorimetry}
CpCu=24.44
CpAu=25.}

! comment this out on first run:
!transfermesh("afrl_mesh_2.xfr")
{Zbottom=0
ZSubstrate=630
ZBuffer=880
ZActive=882.25
ZContact=882.27
ZTop=882.58}

zscale1=1/2
zscale=zscale1
zscale2=20

Zpackage=630*Zscale1
ZSiC=250*Zscale1
ZGaN=2.248*Zscale1
ZChannel=0.02*Zscale2
ZGate=0.31*Zscale1



!ws = w*zscale2
!ls = long*zscale1
initial values
    !Temp = 60+40*exp(-z/100)
Temp=25

equations
 !div ( k * grad(Temp) ) + Q = Rho * Cp * dt(Temp)
  ! div[k*grad(Temp)] + Q = 0        { the heat equation }
dx[k*dx(Temp)]/zscale + dy[k*dy(Temp)]/zscale + dz[k*zscale*dz(Temp)] + Q/zscale = 0
Extrusion
Z=0,Zpackage,Zpackage+ZSic,Zpackage+Zsic+Zgan,Zpackage+Zsic+Zgan+Zchannel,Zpackage+Zsic+Zgan+Zchannel+ZGate
{Surface 'Bottom' Z=0
Layer 'Package'
Surface 'Substrate'  Z=630
Layer 'SiC'
Surface 'Buffer' Z=880
Layer 'GaN'
Surface 'Active Layer' z=882.25   !Z=882.248
Layer 'Channel'
Surface 'Contact' z=882.27   !Z=882.268
Layer 'Gate'
Surface 'Top' z=882.58  !Z=882.578}

BOUNDARIES
Surface 1 Value(temp)=100
Surface 6 Natural(temp)=h*(25-temp)


Region 1 'Package'
Layer {'Package'} 1 k=kcu Q=0
Layer {'SiC'} 2  Void !k=ksic Q=0 !Rho=RhoSic Cp= CpSic
Layer {'GaN'} 3 Void !k=kgan Q=0 !Rho=RhoGaN Cp=CpGaN
Layer {'Channel'} 4 Void
Layer {'Gate'} 5 Void
start (-PackageX,-PackageY) Natural(temp)=h*(25-temp)    !(-487.5,-1212.5)
line to (-PackageX,PackageY)
line	to (PackageX,PackageY)
line	to (PackageX,-PackageY)
	line to close



limited Region  2 'SiC'
!Layer 'Package' k=kcu Q=0 ! Rho=RhoCu Cp=CpCu
Layer {'SiC'} 2  k=ksic Q=0 !Rho=RhoSic Cp= CpSic
Layer {'GaN'} 3 k=kgan Q=0 !Rho=RhoGaN Cp=CpGaN
layer {'channel'} 4 k=kgan q=0
Layer {'Gate'} 5 Void
start (-SubstrateX,-SubstrateY) Natural(temp)=h*(25-temp)
line to (-SubstrateX,SubstrateY)
line	to (SubstrateX,SubstrateY)
	to (SubstrateX,-SubstrateY)
	line to close

Limited Region 3 'Active Layer'

Layer {'Channel'} 4 K=kgan q=0
Zscale=zscale2
Layer {'Gate'} 5 Void
start (-SubstrateX,-SubstrateY)  Natural(temp)=h*(25-temp)
Layer {'Channel'} 4 Load(Temp)=h*(25-temp)/zscale2
line to (-SubstrateX,SubstrateY)
	to (SubstrateX,SubstrateY)
	to (SubstrateX,-SubstrateY)
	line to close



Limited Region 4 'Active Region'
layer {'Channel'} 4 k=kgan Q=0.5
zscale=zscale2
layer {'gate'} 5 void
start (-ChannelX,-ChannelY) Natural(temp)=h*(25-temp)
layer {'channel'} 4  Load(Temp)=h*(25-temp)/zscale2
line to (-ChannelX,ChannelY)
to(ChannelX,ChannelY)
to (ChannelX,-ChannelY)
to close


 Limited Region 5 'Gate'
layer {'gate'} 5 k=kau q=0
start (-GateX2,-GateY) Natural(temp)=h*(25-temp)
line to (-GateX2,GateY)
line	to (-GateX1,GateY)
	to (-GateX1,-GateY)
	line to close

start (GateX1,-GateY) Natural(temp)=h*(25-temp)
line to (GateX1,GateY)
line	to (GateX2,GateY)
	to (GateX2,-GateY)
	line to close

!TIME 0 TO 10 ! by 1   { if time dependent}
plots
 	
!for t=1
!for cycle=100
grid(x,y,z)
grid(x,z) on y=0
grid(y,z) on x=0
grid (y,z) on x=0 zoom (-20,600,40,283)
!grid(x,y) on 'active region'
!contour(TEMP) painted on 'active region'  as 'XY Temp'
 contour(TEMP) painted on x=0  as "YZ Temp"
contour(TEMP) painted on y=0  as "XZ Temp"
 elevation(TEMP) painted from (-488,0,0) to (488,0,0)  as "X-Axis Temp" !range=(0,tmax)
      elevation(TEMP) painted from (0,-1213,0) to (0,1213,0)  as "Y-Axis Temp" !range=(0,tmax)
      elevation(TEMP) painted from (0,0,0) to (0,0,883)  as "Z-Axis Temp" !range=(0,tmax)}
 surface(temp) on x=0
surface(temp) on y=0
!surface (temp) on 'active region'
{for t=0,endtime  transfer(temp) file="afrl_mesh.xfr"
histories
    history(Temp) at (0,0,882.578)
	(0,0, 882.268)
	(0,0, 882.248)
	(0,0,880)
	(0,0,630)
   history(Temp) at (15.5,0,882.578)
	(15.5,0,882.268)
	(15.5,0,882.248)
	(15.5,0,880)
	(0,0,630)}



end