{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 3: Excess Carriers In Semiconductors" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.10: Ratio_of_donor_atoms_to_Si_atom.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.10\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "Rho = 9.6 * 10^-2;// in ohm-m\n", "Sigma_n = 1/Rho;// in (ohm-m)^-1\n", "q = 1.6 * 10^-19;// in C\n", "Mu_n = 1300 * 10^-4;// in m^2/V-sec\n", "N_D = Sigma_n / (Mu_n * q);// in atoms/m^3\n", "A_D = 5*10^22;// Atom density in atoms/cm^3\n", "A_D = A_D * 10^6;// atoms/m^3\n", "R_si = N_D/A_D;// ratio\n", "disp(R_si,'The ratio of donor atom to silicon atom is');\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.11: Equillibrium_electron_and_hole_densities.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.11\n", "format('v',9)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "n_i = 1.5 * 10^10;// in per cm^3\n", "n_n = 2.25 * 10^15;// in per cm^3\n", "p_n = (n_i)^2/n_n;// in per cm^3\n", "disp(p_n,'The equilibrium electron per cm^3 is');\n", "h_n = n_n;// in cm^3\n", "disp(h_n,'Hole densities in per cm^3 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.12: Carrier_concentration.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.12\n", "format('v',7)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "N_A = 2 * 10^16;// in atoms/cm^3\n", "N_D = 10^16;// in atoms/cm^3\n", "C_c = N_A-N_D;// C_c stands for Carrier concentration in /cm^3\n", "disp(C_c,'Carrier concentration per cm^3 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.13: Generation_rate_due_to_irradiation.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.13\n", "format('v',7)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "del_n = 10^15;// in cm^3\n", "Torque_p = 10 * 10^-6;// in sec\n", "R_g = del_n/Torque_p;// in hole pairs/sec/cm^3\n", "disp(R_g,'The rate of generation of minority carrier in electron hole pairs/sec/cm^3 is ');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.14: Mobility_of_minority_charge_carrier.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.14\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "v = 1/(20 * 10^-6);// in cm/sec\n", "E = 10;// in V/cm\n", "Mu= v/E;// in cm^2/V-sec\n", "disp(Mu,'The mobility of minority charge carrier in cm^2/V-sec is ');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.15: Hall_and_electron_diffusion_current.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.15\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "q = 1.6 * 10^-19;// in C\n", "N_D = 4.5 * 10^15;// in /cm^3\n", "del_p = 10^21;\n", "e=10;// in cm\n", "A = 1;// in mm^2\n", "A = A * 10^-14;// cm^2\n", "l = 10;// in cm\n", "Torque_p = 1;// in microsec\n", "Torque_p = Torque_p * 10^-6;// in sec\n", "Torque_n = 1;// in microsec\n", "Torque_n = Torque_n * 10^-6;// in sec\n", "n_i = 1.5 * 10^10;// in /cm^3\n", "D_n = 30;// in cm^2/sec\n", "D_p = 12;// in cm^2/sec\n", "n_o = N_D;// in /cm^3\n", "p_o = (n_i)^2/n_o;// in /cm^3\n", "disp(p_o,'Hole concentration at thermal equilibrium per cm^3 is');\n", "l_n = sqrt(D_n * Torque_n);// in cm\n", "disp(l_n,'Diffusion length of electron in cm is');\n", "l_p = sqrt(D_p * Torque_p);// in cm\n", "disp(l_p,'Diffusion length of holes in cm is');\n", "x=34.6*10^-4;// in cm\n", "dpBYdx = del_p *e;// in cm^4\n", "disp(dpBYdx,'Concentration gradient of holes at distance in cm^4 is');\n", "e1 = 1.88 * 10^1;// in cm\n", "dnBYdx = del_p * e1;// in cm^4 \n", "disp(dnBYdx,'Concentration gradient of electrons in per cm^4 is');\n", "J_P = -(q) * D_p * dpBYdx;// in A/cm^2\n", "disp(J_P,'Current density of holes due to diffusion in A/cm^2 is');\n", "J_n = q * D_n * dnBYdx;// in A/cm^2\n", "disp(J_n,'Current density of electrons due to diffusion in A/cm^2 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.16: Energy_band_gap_of_semiconductor_material_used.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.16\n", "format('v',5)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "e= 1.6*10^-19;// electron charge in C\n", "h = 6.626 * 10^-34;// in J-s\n", "h= h/e;// in eV\n", "c = 3 * 10^8;// in m/s\n", "lembda = 5490 * 10^-10;// in m\n", "f = c/lembda;\n", "E = h * f;// in eV\n", "disp(E,'The energy band gap of the semiconductor material in eV is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.17: Current_density_in_Si.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.17\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "y2 = 6 * 10^16;// in /cm^3\n", "y1 = 10^17;// in /cm^3\n", "x2 = 2;// in µm\n", "x1 = 0;// in µm\n", "D_n = 35;// in cm^2/sec\n", "q = 1.6 *10^-19;// in C\n", "dnBYdx = (y2 - y1)/((x2-x1) * 10^-4);\n", "J_n = q * D_n * dnBYdx;// in A/cm^2\n", "disp(J_n,'The current density in silicon in A/cm^2 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.18: Resistance_of_the_bar.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.18\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "q = 1.6 * 10^-19;// in C\n", "n_n = 5 * 10^20;// in /m^3\n", "n_n = n_n * 10^-6;// in cm^3\n", "Mu_n = 0.13;// in m^2/V-sec\n", "Mu_n = Mu_n * 10^4;// in cm^2/V-sec\n", "Sigma_n = q * n_n * Mu_n;// in (ohm-cm)^-1\n", "Rho = 1/Sigma_n;// in Ω-cm\n", "l = 0.1;// in cm\n", "A = 100;// µm^2\n", "A = A * 10^-8;// in cm^2\n", "R = Rho * (l/A);// in Ohm\n", "R=round(R*10^-6);// in MΩ\n", "disp(R,'The resistance of the bar in MΩ is'); " ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.19: Depletion_width.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.19\n", "format('v',5)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "t_d = 3;// total depletion in µm\n", "// The depletion width ,\n", "D = t_d/9;// in µm\n", "disp(D,'Depletion width in µm is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.1: Hole_concentration_at_equilibrium.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.1\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "N_d = 10^17;// atoms/cm^3\n", "n_i = 1.5 * 10^10;// in /cm^3\n", "n_o = 10^17;// in cm^3\n", "// p_o * n_o = (n_i)^2\n", "p_o = (n_i)^2 / n_o;//in holes/cm^3\n", "disp(p_o,'The hole concentration at equilibrium in holes/cm^3 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.20: Minority_carrier_density.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.20\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "n_i = 1.5 * 10^16;// in /m^3\n", "n_n = 5 * 10^20;// in /m^3\n", "p_n = (n_i)^2/n_n;// in /m^3\n", "disp(p_n,'The majority carrier density per m^3 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.21: Collector_current_density.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.21\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "D_n = 25;// in cm^2/sec\n", "q = 1.6 * 10^-19;// in C\n", "y2 = 10^14;// in /cm^3\n", "y1 = 0;// in /cm^3\n", "x2 = 0;//in µm\n", "x1 = 0.5;// in µm\n", "x1 = x1 * 10^-4;// in cm\n", "dnBYdx = abs((y2-y1)/(x2-x1));// in /cm^4 \n", "// The collector current density \n", "J_n = q * D_n * (dnBYdx);// in /cm^4\n", "J_n = J_n * 10^-1;// in A/cm^2\n", "disp(J_n,'The collector current density in A/cm^2 is');\n", "\n", "// Note: In the book, the calculated value of dn by dx (2*10^19) is wrong. Correct value is 2*10^18 so the answer in the book is wrong." ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.22: Band_gap.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "//Exa 3.22\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "h = 6.64 * 10^-34;// in J-s\n", "e= 1.6*10^-19;// electron charge in C\n", "c= 3 * 10^8;// in m/s\n", "lembda = 0.87;// in µm\n", "lembda = lembda * 10^-6;// in m\n", "E_g = (h * c)/lembda;// in J-s\n", "E_g= E_g/e;// in eV\n", "disp(E_g,'The band gap of the material in eV is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.23: Total_energy_absorbed_by_sample.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.23\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "I_o = 10;// in mW\n", "e = 1.6 * 10^-19;// in J/eV\n", "hv = 2;// in eV\n", "hv1=1.43;// in eV\n", "alpha = 5 * 10^4;// in cm^-1\n", "l = 46;// in µm\n", "l = l * 10^-6;// in m\n", "I_t = round(I_o * exp(-(alpha) * l));// in mW\n", "AbsorbedPower= I_o-I_t;// in mW\n", "AbsorbedPower=AbsorbedPower*10^-3;// in W or J/s\n", "disp(AbsorbedPower,'The absorbed power in watt or J/s is');\n", "F= (hv-hv1)/hv;// fraction of each photon energy unit\n", "EnergyConToHeat= AbsorbedPower*F;// in J/s\n", "disp(EnergyConToHeat,'The amount of energy converted to heat per second in J/s is : ')\n", "A= (AbsorbedPower-EnergyConToHeat)/(e*hv1);\n", "disp(A,'The number of photon per sec given off from recombination events in photons/s is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.24: Hole_current.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.24\n", "format('v',9)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "Mu_p = 500;// in cm^2/V-sec\n", "kT = 0.0259;\n", "Toh_p = 10^-10;// in sec\n", "p_o = 10^17;// in cm^-3\n", "q= 1.6*10^-19;// in C\n", "A=0.5;// in square meter\n", "del_p = 5 * 10^16;// in cm^-3\n", "n_i= 1.5*10^10;// in cm^-3 \n", "D_p = kT * Mu_p;// in cm/s\n", "L_p = sqrt(D_p * Toh_p);// in cm\n", "x = 10^-5;// in cm\n", "p = p_o+del_p* %e^(x/L_p);// in cm^-3\n", "// p= n_i*%e^(Eip)/kT where Eip=E_i-F_p\n", "Eip= log(p/n_i)*kT;// in eV\n", "Ecp= 1.1/2-Eip;// value of E_c-E_p in eV\n", "Ip= q*A*D_p/L_p*del_p/%e^(x/L_p);// in A\n", "disp(Ip,'The hole current in A is : ')\n", "Qp= q*A*del_p*L_p;// in C\n", "disp(Qp,'The value of Qp in C is : ')\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.3: Position_of_Fermi_level.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.3\n", "format('v',6)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "n_i = 1.5 * 10 ^10;// in /cm^3 for silicon\n", "N_d = 10^17;// in atoms/cm^3\n", "n_o = 10^17;// electrons/cm^3\n", "KT = 0.0259;\n", "// E_r - E_i = KT * log(n_o/n_i)\n", "del_E = KT * log(n_o/n_i);// in eV\n", "disp('The energy band for this type material is Ei + '+string(del_E)+' eV');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.4: Diffusion_coefficients_of_electrons_and_holes.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.4\n", "format('v',7)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "K = 1.38 * 10^-23;// in J/K\n", "T = 27;// in degree\n", "T = T + 273;// in K\n", "e = 1.6 * 10^-19;// in C\n", "Mu_e = 0.17;// in m^2/v-s\n", "Mu_e1 = 0.025;// in m^2/v-s\n", "D_n = ((K * T)/e) * Mu_e;// in m^2/s\n", "disp(D_n,'The diffusion coefficient of electrons in m^2/s is');\n", "D_p = ((K * T)/e) * Mu_e1;// in m^2/s\n", "disp(D_p,'The diffusion coefficient of holes in m^2/s is ');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.5: Diffusion_length.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.5\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "Mu_n = 0.15;// in m^2/v-s\n", "K = 1.38 * 10^-23; // in J/K\n", "T = 300;// in K\n", "del_n = 10^20;// in per m^3\n", "Toh_n = 10^-7;// in s\n", "e = 1.6 * 10^-19;// in C\n", "D_n = Mu_n * ((K * T)/e);// in m^2/s\n", "disp(D_n,'The diffusion coefficient in m^2/s is');\n", "L_n = sqrt(D_n * Toh_n);// in m \n", "disp(L_n,'The Diffusion length in m is');\n", "J_n = (e * D_n * del_n)/L_n;// in A/m^2\n", "disp(J_n,'The diffusion current density in A/m^2 is'); \n", "// Note : The value of diffusion coefficient in the book is wrong.\n", "\n", "" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.6: Concentration_of_holes_and_electrons.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.6\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "Sigma = 0.1;// in (ohm-m)^-1\n", "Mu_n = 1300;\n", "n_i = 1.5 * 10^10;\n", "q = 1.6 * 10^-19;// in C\n", "n_n = Sigma/(Mu_n * q);// in electrons/cm^3\n", "n_n= n_n*10^6;// per m^3\n", "disp(n_n,'The concentration of electrons per m^3 is');\n", "p_n = (n_i)^2/n_n;// in per cm^3\n", "p_n = p_n * 10^6;// in per m^3\n", "disp(p_n,'The concentration of holes per m^3 is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.7: Electron_transit_time.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.7\n", "format('v',9)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "Mu_e = 0.13;// in m^2/v-s\n", "Mu_h = 0.05;// in m^2/v-s\n", "Toh_h = 10^-6;// in s\n", "L = 100;// in µm\n", "L = L * 10^-6;// in m\n", "V = 2;// in V\n", "t_n =L^2/(Mu_e * V);// in s\n", "disp(t_n,'Electron transit time in seconds is');\n", "p_g = (Toh_h/t_n) * (1 + Mu_h/Mu_e);//photo conductor gain \n", "disp(p_g,'Photo conductor gain is');\n", "\n", "// Note: There is a calculation error to evaluate the value of t_n. So the answer in the book is wrong" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.8: Resistivity_of_intrinsic_Ge.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.8\n", "format('v',5)\n", "clc;\n", "clear;\n", "close;\n", "//Given data\n", "n_i = 2.5 * 10^13;\n", "Mu_n = 3800;\n", "Mu_p = 1800;\n", "q = 1.6 * 10^-19;// in C\n", "Sigma = n_i * (Mu_n + Mu_p) * q;// in (ohm-cm)^-1\n", "Rho = 1/Sigma;// in ohm-cm\n", "Rho= round(Rho);\n", "disp(Rho,'The resistivity of intrinsic germanium in ohm-cm is');\n", "N_D = 4.4 * 10^22/(1*10^8);// in atoms/cm^3\n", "Sigma_n = N_D * Mu_n * q;// in (ohm-cm)^-1\n", "Rho_n = 1/Sigma_n;// in ohm-cm\n", "disp(Rho_n,'If a donor type impurity is added to the extent of 1 atom per 10^8 Ge atoms, then the resistivity drops in ohm-cm is');" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3.9: Hole_and_electron_concentration.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Exa 3.9\n", "format('v',8)\n", "clc;\n", "clear;\n", "close;\n", "// Given data\n", "n_i = 10^16;// in /m3\n", "N_D = 10^22;// in /m^3\n", "n = N_D;// in /m^3\n", "disp(n,'Electron concentration per m^3 is');\n", "p = (n_i)^2/n;// in /m^3\n", "disp(p,'Hole concentration per m^3 is');" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }