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{
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"metadata": {},
"source": [
"# Chapter 3 Semoconductor Devices Fundamentals"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Exa 3.2 page no:35"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
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"text": [
"resistivity of the si doped with n−dopant is : \n",
"0.089 ohm−cm \n"
]
}
],
"source": [
"def resistivity(u,n): #n:doped concentration =10**17 atoms/cubic cm, u: mobility of electrons =700square cm/v−sec .\n",
" q=1.6*10**-19 #q: charge\n",
" Res=1/(q*u*n)# since P is neglegible . \n",
" print \"resistivity of the si doped with n−dopant is : \"\n",
" print \"%0.3f ohm−cm \"%Res \n",
"resistivity(10**17,700)\n",
"# after executing calling resitivity ( u=700 and n =10ˆ17)i .e. , resistivity (10ˆ17 ,700) ;"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Exa 3.3 page no:35"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"resistivity of intrinsic Ge is : \n",
"2595245510.225 ohm−cm \n"
]
}
],
"source": [
"def resistivity(un,np): # un: electron concentration , up: hole concentration\n",
" q=1.6*10**-19 #in coulumb \n",
" ni=2.5*10*13 # concentration in cmˆ−3 \n",
" Res=1/(q*ni*un*np) # since n=p=ni \n",
" print \"resistivity of intrinsic Ge is : \"\n",
" print \"%0.3f ohm−cm \"%Res \n",
"resistivity(3900,1900)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Exa 3.4 page no:37"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hole concentrartion at 300K is : \n",
"2250.000000 per cubic cm \n"
]
}
],
"source": [
"def holeconcentration(ni,Nd): # Nd: donar concentration ; since , Nd>>ni , so Nd=n=10ˆ17 atoms/cmˆ3.\n",
" p=ni**2/Nd\n",
" print \"hole concentrartion at 300K is : \"\n",
" print \"%f per cubic cm \"%p\n",
"holeconcentration(1.5*10**10,10**17);"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Exa 3.5 page no:39"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"resistivity of the copper is : \n",
"2.29779411765e-08 ohm−meter\n"
]
}
],
"source": [
"q=1.6*10**-19;\n",
"n=8.5*10**28;\n",
"u=3.2*10**-3;\n",
"p=1/(n*q*u);\n",
"print \"resistivity of the copper is : \"\n",
"print p,\" ohm−meter\"\n",
"# 2.298D−08 means 2.298∗10ˆ −8"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Exa 3.6 page no:41"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Cu is: 0.0570814666846 pF\n",
"Ccs is: 0.282102806737 pF\n",
"gm is : 7.7519379845 mA/V\n",
"C1 is: 3.32558139535 pF\n",
"R1 is: 25.8 kilo ohm\n",
"R0 is 645.0 kilo Ohm \n",
"Ru is: 1290.0 Mega Ohm \n"
]
}
],
"source": [
"from math import sqrt\n",
"\n",
"Cuo=0.25; # collector −base depletion region capacitance in pico Farad(pF) for zero bias\n",
"Ccso=1.5 ; # collector −substrate junction capacitance in pico Farad(pF) for zero bias\n",
"q=1.6*10**-19 ; # electron charge in coulomb\n",
"Ic=0.2 ; #collector current in ampere(A)\n",
"k=8.6*10**-5; #in eV/K, where 1eV=1.6∗10ˆ−19\n",
"T=300; # absolute temperature in kelvin (K)\n",
"Vcb=10 ; #forward bias on the junction in volt(v)\n",
"Vcs=15 ; # collector −substrate bias in volt (V)\n",
"Cje=1 ; #depletion region capacitance in pico Farad(pF)\n",
"Bo=200; #small signal current gain\n",
"Tf=0.3; #transit time in forward direction in nano seconds (nS)\n",
"n=2*10**-4; # proportionality constant for Ro and gm\n",
"Vo=0.55; # bias voltage in volt (V)\n",
"Cu=Cuo/sqrt(1+(Vcb/Vo));# collector −base capacitance\n",
"print \"Cu is: \",Cu,\" pF\"\n",
"Ccs=Ccso/sqrt(1+(Vcs/Vo)); # capacitance collector −substrate\n",
"print \"Ccs is: \",Ccs,\"pF\"\n",
"gm=q*Ic/(k*T*1.6*10**-19);# since k is in eV so converting it in Coulomb/Kelvin\n",
"print \"gm is :\",gm,\"mA/V\"# transconductance of the bipolar transistor here\n",
"Cb=Tf*gm;# diffusion capacitance in pico Farad(pF)\n",
"C1=Cb+Cje;#small signal capacitance of bipolar transistor\n",
"print \"C1 is: \",C1,\"pF\"\n",
"R1=Bo/gm;# small signal input resistance of bipolar transistor\n",
"print \"R1 is: \",R1,\" kilo ohm\"\n",
"Ro=1/(n*gm);#small signal output resistance\n",
"print \"R0 is \",Ro,\" kilo Ohm \"\n",
"Ru=10*Bo*Ro/10**3;# collector −base resistance\n",
"print \"Ru is: \",Ru,\"Mega Ohm \""
]
}
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