Appendix F - Sample Medici File

As mentioned previously, the Medici simulations used in this thesis were almost all defined as one-dimensional structures with 300 equally-spaced nodes. The integrity of this approach was confirmed by running several simulations with different gridding for each structure, to ensure that the 300-node gridding was sufficiently fine that a small change in grid spacing would not affect the simulation results.

The following Medici batch-file was used to generate the simulation results for DF5. Since the circuit conditions ensured that the diode operated at voltages well below breakdown, the "IMPACT.I" impact ionization parameter was not included in the "MODELS" statement. This parameter was of course included for the breakdown simulations reported in Chapter 4. (As mentioned in Chapter 4, the default ionization parameters were used, which are based on the generally-accepted Van Overstraeten and De Man data [Van70] for ionization rates in silicon.)

TITLE June 16, 1996 - data for "DF5" figures in Chapter 5 of thesis

COMMENT set up mesh

MESH RECTANGU OUT.FILE=df5mesh

X.MESH WIDTH=1000000 N.SPACES=1

Y.MESH DEPTH=212 N.SPACES=300

COMMENT define region

REGION NUM=1 SILICON

COMMENT define electrodes

ELECTRODE NUM=1 TOP

ELECTRODE NUM=2 BOT

COMMENT define impurity profile

PROFILE p-TYPE N.PEAK=1.2E14 UNIFORM

PROFILE p-TYPE N.PEAK=1E19 Y.MIN=0 Y.MAX=0 Y.CHAR=29.7

PROFILE N-TYPE N.PEAK=1E19 Y.MIN=212 Y.MAX=212 Y.CHAR=29.7

COMMENT show doping

PLOT.1D DOPING Y.LOG COLOR=2 LINE=1 BOT=1E10 TOP=1E20

+ X.STA=0 X.END=0 Y.STA=0 Y.END=150

+ TITLE="df5 - DOPING PROFILE"

+ DEVICE=POSTSCRIPT PLOT.OUT=df5dop.ps

COMMENT Attach a lumped resistance to the p+ contact

CONTACT NUM=1 RESIST=50

COMMENT Specify physical models to use

MODELS CONSRH AUGER CONMOB FLDMOB

MATERIAL SILICON TAUN0=55E-9 TAUP0=55E-9

COMMENT Symbolic factorization

SYMB NEWTON CARRIERS=2

method stacks=10

COMMENT Perform a + volt steady state solution, then simulate

COMMENT the transient turn-off characteristics for the diode.

SOLVE V1=0 OUT.FILE=df5.s00

SOLVE V1=12 OUT.FILE=df5.s01

SOLVE V1=-300 TSTEP=0.1E-9 TSTOP=8E-9 dt.max=0.025 OUT.FILE=df5.s02

COMMENT Plot the diode current

PLOT.1D X.AXIS=TIME Y.AXIS=I1 POINTS TOP=1 BOT=-7 RIGHT=8E-9

+ TITLE="df5 Current vs. Time" COLOR=2

+ DEVICE=POSTSCRIPT PLOT.OUT=df5cur.ps out.file=df5cur.dat