GaAs MESFET Gate Simulation - 1D

DESCRIPTION

This example simulates a simple 1D GaAs MESFET structure underneath the gate. This utilizes SUPREM-IV.GS's new true 1D mode. First, the 1D grid is set up and initialized with carbon as a background dopant. Beryllium and silicon are implanted into GaAs. Note that silicon as an impurity is designated as "isilicon". The as-implanted dopant concentration-depth profiles are plotted in 1D in Figure 1. Next an anneal step is done, using the Fermi method, and the diffused beryllium profile is then plotted in the same figure. The hump in the beryllium profile at the beryllium/silicon junction is due to the electric field effect on diffusion. Since the beryllium was implanted, the implanted diffusivity numbers (as opposed to the grown-in numbers) are used. The input file for the simulation is in the "examples/exam10" directory, in the file example10.in.

option quiet
set echo

mode one.dim
line x loc=0.0 spacing=0.01 tag=top
line x loc=1.0 spacing=0.01
line x loc=20 spacing=0.25 tag=bottom

region gaas       xlo=top  xhi=bottom
boundary exposed  xlo=top xhi=top
boundary backside xlo=bottom xhi=bottom

init carbon conc=1e15
implant beryllium dose=2e13 energy=100 pearson
implant isilicon dose=5e13 energy=50 pearson

#beryllium gaas Dip.0=2.1e-8 Dip.E=1.74
beryllium gaas /nitride Seg.0=.5 Seg.E=0

deposit nitride thick=.3

    select z=log10(beryllium)
    plot.1d x.min=0 x.ma=2 y.mi=14 y.max=20 line.type=2
    select z=log10(isilicon)
    plot.1d x.min=0 x.ma=2 y.mi=14 y.max=20 cle=f axi=f line.type=3
    select z=log10(carbon)
    plot.1d x.min=0 x.ma=2 y.mi=14 y.max=20 cle=f axi=f line.type=4

method fermi init=1e-5
method full.fac
diffuse time=15 temp=800 argon 
    select z=log10(beryllium)
    plot.1d x.min=0 x.ma=2 y.mi=14 y.max=20 cle=f axi=f line.type=5

quit

If you wish to change the beryllium diffusivity parameters, you would uncomment the line:

#beryllium gaas Dip.0=2.1e-8 Dip.E=1.74

and put in your own values.