Chapter 10: Crystal Growth and Epitaxy

Example 10.1 Page 337

In [1]:
#initialisation of variable
from math import *
N=10**16;#atoms concentration
m=60;#mass
A=10.8 #atomic weight
d=2.53;#density
k=.8;#constant
Na=6.02*10**23;#avagadro's no.

#calculation
C=N/k;#initial concentration
V=m*10**3/d;#volume
Nb=C*V;#no. of bororn atoms
M=Nb*A/Na;#mass

#result
print"initial concentration is",round(C,2),"boron atoms/cm^3"
print"mass of boron added is",round(M*1000,3),"mg"

initial concentration is 1.25e+16 boron atoms/cm^3
mass of boron added is 5.318 mg

Example 10.3 Page 359

In [3]:
#initialisation of variable
from math import *
T=300;#K
D=3.64;#diameter
Ns=7.54*10**14;#concentration
P1=1;#pressure
P2=10**-4;#pressure
P3=10**-8;#pressure
M=32;#mass

#calculation
t1=Ns*(M*T)**.5/(2.64*10**20*P1);#time for P1
t2=Ns*(M*T)**.5/(2.64*10**20*P2);#time for P2
t3=Ns*(M*T)**.5/(2.64*10**20*P3);#time for P3

#result 
print"time for P1 is",round(t1*1000,2),"ms"
print"time for P2 is",round(t2,2),"s"
print"time for P3 is",round(t3/3600,2),"hr"

time for P1 is 0.28 ms
time for P2 is 2.8 s
time for P3 is 7.77 hr

Example 10.4 Page 360

In [2]:
#initialisation of variable
from math import *
A=.5;#area
L=10;#length
T=1173;#temperature
t=2.8;#thickness
d=6*10**14;#surface density
k=2.54*10**20;
P1=5.5*10**-2;#pressure
P2=1.1;#pressure
M1=69.72;#Mol.Wt of Ga
M2=74.92*2;#Mol.Wt of As2

#calculation
A1=k*P1*A/(M1*T)**.5/(3*L**2);#arrival rate
A2=k*P2*A/(M2*T)**.5/(3*L**2);#arrival rate
G=A1*t/d;#growth rate

#result
print"growth rate of GaAs2 is",round(G*60,0),"nm/min"

growth rate of GaAs2 is 23.0 nm/min