Chapter 9:Integrated Circuit Fabrication

Example 9.2,Page number 470

In [9]:
#Variable declaration
t=1                   #thickness(mil)         
e=1.6*10**-19         #charge on electron(C)
Pp=10**17             #concentration of phosphorous(atoms/cm^3)
Bn=5*10**16           #boron concentration(atoms/cm^3)
un=.135               #mobility(m^2/Vs)

#Calculations
n=(Pp-Bn)*10**6       #net concentration(atoms/cm^3)
g=e*un*n              #conductivity()
rho=10**6/(g*25)      #resistivity(ohm mil)
Rs=rho/t              #sheet resistance(ohm mil^2)

#Results
print"Sheet resistance is",round(Rs),"ohm(mil**2)"

Sheet resistance is 37.0 ohm(mil**2)

Example 9.3,Page number 471

In [2]:
#Variable declaration
R=20*10**3              #resistance of resistor(ohms)
w=25                    #width(um)
Rs=200                  #sheet resistance(ohm/square)
R1=5*10**3              #resistance(ohms)

#Calculations
#Part a
l=(R*w)/Rs              #length required to fabricate 20 kohms(um)

#Part b
L=25             #length of resistor of 5 k ohms(um)
w1=(Rs*L)/R1     #width required to fabricate 5 kohms(um)
#Results
print"length required to fabricate 20 kohms resistor is",l,"um"
print"width required to fabricate 5 kohms resistor is",w1,"um"

length required to fabricate 20 kohms resistor is 2500 um
width required to fabricate 5 kohms resistor is 1 um

Example 9.4,Page number 471

In [2]:
#Variable declaration
C=0.4*10**-12               #capacitance(pF/um^2)
A=10**-12                   #area of film(m^2)
d=400*10**-10               #thickness of SiO2(amstrong)
Eo=8.849*10**-12            #absolute electrical permitivity of free space

#Calculations
Er=(C*d)/(Eo*A)             #relative dielectric constant

#Results
print"relative dielectric constant of SiO2 is",round(Er),"(Solution given in the textbook is incorrect)"

relative dielectric constant of SiO2 is 1808.0 (Solution given in the textbook is incorrect)

Example 9.5,Page number 471

In [8]:
#Variable declaration
C=250*10**-12               #capacitance(pF)
d=500*10**-10               #thickness of SiO2 layer(amstrong)
Eo=8.849*10**-12            #absolute electrical permitivity of free space
Er=3.5                      #relative dielectric constant

#Calculations
A=(C*d)/(Eo*Er)            #chip area(um^2)

#Results
print"chip area needed for a 250 pF  MOS capacitor",round(A/1e-7,2),"(um)^2(Solution given in the textbook is incorrect)"

chip area needed for a 250 pF  MOS capacitor 4.04 (um)^2(Solution given in the textbook is incorrect)
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