advertisement

Tutorials 2E8 – Semiconductor materials II 1. Calculate the approximate donor binding energy for Ge (r=16, mn*= 0.12m0) ? 2. In which group (column) of the Periodical Table of Elements do Silicon and Germanium belong? 3. Name a few elemental semiconductor materials and compound semiconductor materials (at least 2 of each type). 4. What are the main differences between semiconductive, insulative and conductive materials? 1 5. Calculate the electrical conductivity of pure Si at 20ºC and 150ºC. For Si at room temperature, the energy gap Eg = 1.1 eV, the intrinsic carrier concentration ni =1.5 x 1016 /m3, the electron mobility μn = 0.135 m2/Vs, and the hole mobility μp = 0.048 m2/Vs. 2 6. A Si sample is doped with 1017 Arsenic (As) atoms/cm3. What is the equilibrium hole concentration p at 300 K? Where is EF relative to Ei? For Si ni = 1.5x1010 cm-3? 3 DATA SHEET: Free electron rest mass mo Boltzmann’s constant k 9.11xl0-31kg 1.38 x 10-23 J/oK = 8.618x10-5 eV/K Planck’s constant h 6.63x10-34 J s Electronic charge q Intrinsic carrier concentration of Si ni 1.6 x 10-19 C 1.5 x 1010 cm-3 Room temperature value of kT 0.0259 eV Energy band gap Eg of Si 1.1 eV Permittivity of vacuum 0 8.85 x 10-14F/cm Reduced Planck’s constant h / 2 Speed of light 3 x 108 m/s ΔT=1 oC = 1 K = 1.8°F; 1W = 3.41214 BTU/h; 1 ft = 0.3048 m; 1 ft = 12 in mn* q 4 Eb 2 K 22 ; K 40 r ; f ( E F ) 1 exp ( E F E F ) / kT 1 N c 2( 2mn* kT 3 / 2 ) h2 ; 𝜎 = 𝑛𝑖 𝑞(𝜇𝑛 + 𝜇𝑝 ); t t l0 ; ; 2m *p kT h2 1 1 exp ( E E F ) / kT ; n0 ; 1/ )3/ 2 p0 N v exp ( EF Ev ) / kT ; ni N c N v e Eg / 2 kT k 𝜎 = 𝜎0 exp(− ; q d A t t ; f ( E ) N ( E )dE Ec n0 ni exp ( EF Ei ) / kT ; ; C k 0 A / d 1 1 11 2 N v 2( n0 N c exp ( Ec EF ) / kT n 0 p0 ni2 f (E) 𝐸𝑔 2𝐾𝑇 l t l0 p0 ni exp ( Ei E F ) / kT ; ); 𝜎𝑛 = 𝑛0 𝑞𝜇𝑛 ; 𝜎𝑝 = 𝑝0 𝑞𝜇𝑝 ; ; F I l B Sin ; R l A ; n c/v; vl f 4