1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
{
"metadata": {
"name": "",
"signature": "sha256:ba1924948de9c5df666fb8372fa076fb175eef8afac1d23c28cb6aaf92d05c98"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 15 :\n",
"Semiconductors"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.1 Page No : 520"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"import math \n",
"\n",
"# Variables\n",
"U_n = 1350.\t\t\t#mobility of electron in cm2/volt-sec \n",
"U_h = 480.\t\t\t#hole mobility in cm2/volt-sec\n",
"\n",
"# Calculation\n",
"Sigma = 1.072*10**10\t\t\t#density of electron hole pair per cc at 300\u00b0K for a pure silicon crystal\n",
"e = 1.6*10**(-19);\t\t\t#charge on the electron in C\n",
"Sigma_i = Sigma*e*(U_n+U_h);\t\t\t#Conductivity of pure silicon crystal\n",
"p_i = 1/(Sigma_i);\t\t\t#Resistivity of silicon crystal in Ohm-cm\n",
"P_i = p_i*10**(-2);\t\t\t#Resistivity of silicon crystal in Ohm-m\n",
"\n",
"# Results\n",
"print 'Conductivity of pure silicon crystal = %.2e mho/cm'%Sigma_i\n",
"print 'Resistivity of silicon crystal = %.2e Ohm-m'%P_i\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Conductivity of pure silicon crystal = 3.14e-06 mho/cm\n",
"Resistivity of silicon crystal = 3.19e+03 Ohm-m\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.2 Page No : 521"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"import math \n",
"\n",
"# Variables\n",
"U = 1200;\t\t\t#electron mobility in cm2/Volt-sec\n",
"e = 1.6*10**(-19);\t\t\t#charge on the electron in C\n",
"\n",
"# Calculation\n",
"n = 10**13;\t\t\t#concentration of phosphorus\n",
"sigma = U*e*n;\t\t\t#conductivity of crystal in mho/cm\n",
"p_i = 1/sigma;\t\t\t#resistivity of silicon wafer if all donor atom are active\n",
"\n",
"# Results\n",
"print 'resistivity of silicon wafer if all donor atom are active is %.1e ohm-cm'%p_i\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"resistivity of silicon wafer if all donor atom are active is 5.2e+02 ohm-cm\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.3 Page No : 521"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"import math \n",
"\n",
"# Variables\n",
"U_n = 3900\t\t\t#mobility of electron in cm2/volt-sec \n",
"U_h = 1900\t\t\t#hole mobility in cm2/volt-sec\n",
"n_i = 2.5*10**13;\t\t\t#concentration of electron\n",
"u_n = U_n*10**(-4);\t\t\t#mobility of electron in m2/volt-sec \n",
"u_h = U_h*10**(-4);\t\t\t#hole mobility in m2/volt-sec\n",
"e = 1.6*10**(-19);\t\t\t#charge on the electron in C\n",
"\n",
"# Calculation\n",
"Sigma_i = n_i*e*(u_n+u_h)*10**6;\t\t\t#Conductivity\n",
"p_i = 1/(Sigma_i);\t\t\t#resistivity of intrinsic germanium rod\n",
"l = 1*10**(-2);\t\t\t#length of germanium rod in m\n",
"w = 1*10**(-3);\t\t\t#width of germanium rod in m\n",
"t = 1*10**(-3);\t\t\t#thick of germanium rod in m\n",
"A = w*t;\t\t\t#Area of cross section in m2\n",
"R = p_i*l/A;\t\t\t#Resistance of an intrinsic germanium rod in Ohm\n",
"\n",
"# Results\n",
"print 'Resistance of an intrinsic germanium rod is %.2f K-Ohm'%(R/10**3)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Resistance of an intrinsic germanium rod is 4.31 K-Ohm\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15.4 Page No : 521"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"import math \n",
"\n",
"# Variables\n",
"N_a = 1.1*10**20;\t\t\t#acceptor density in atoms/m3\n",
"n_i = 2.5*10**19;\t\t\t#concentration of majority carrier per m3 \n",
"\n",
"# Calculation\n",
"n_p = (n_i**2)/N_a;\t\t\t#intrinsic density \n",
"R = n_p/n_i;\t\t\t#Ratio of n_p and n_i\n",
"\n",
"# Results\n",
"print 'n_p/n_i = %.2f'%R\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"n_p/n_i = 0.23\n"
]
}
],
"prompt_number": 1
}
],
"metadata": {}
}
]
}
|
