Physics for Scientists and Engineers
6th Edition
ISBN: 9781429281843
Author: Tipler
Publisher: MAC HIGHER
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Chapter 38, Problem 58P
(a)
To determine
The Fermi factor for electrons at the bottom of the
(b)
To determine
The Fermi factor for an insulator with band gap
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In a phosphorous-doped (n-type) silicon, the Fermi level is shifted upward 0.1 eV.
What is the probability of an electron's being thermally promoted to the conduction band in silicon (Eg = 1.107 eV at 25 deg C?
Your answer must be to 2 significant figures or will be marked wrong.
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The Fermi energy of copper at 300 K is 7.05 eV. (a) What is the average energy of a conduction electron in copper at 300 K? (b) At what temperature would the average translational energy of a molecule in an ideal gas be equal to the energy calculated in part (a)?
The Fermi energy of a doped semiconductor is different from that of a pure semiconductor. Consider silicon, where the energy difference between the top of the valence band and the bottom of the conduction band is 1.11 eV. At a temperature of 300 K the Fermi energy of pure silicon lies approximately between the bottom of the conduction band and the top of the valence band. (a) Calculate the probability of occupying a state at the bottom of the conduction band. Consider now that the silicon has been doped with donor atoms that introduce a state at 0.15 eV below the conduction band background. Doping also caused the Fermi level to be shifted to an energy 0.11 eV below the bottom of the conduction band. (b) Under these conditions, calculate the occupancy of the lower end of the conduction band. (c) Calculate the probability that the level introduced by the donor impurities is occupied.
Chapter 38 Solutions
Physics for Scientists and Engineers
Ch. 38 - Prob. 1PCh. 38 - Prob. 2PCh. 38 - Prob. 3PCh. 38 - Prob. 4PCh. 38 - Prob. 5PCh. 38 - Prob. 6PCh. 38 - Prob. 7PCh. 38 - Prob. 8PCh. 38 - Prob. 9PCh. 38 - Prob. 10P
Ch. 38 - Prob. 11PCh. 38 - Prob. 12PCh. 38 - Prob. 13PCh. 38 - Prob. 14PCh. 38 - Prob. 15PCh. 38 - Prob. 16PCh. 38 - Prob. 17PCh. 38 - Prob. 18PCh. 38 - Prob. 19PCh. 38 - Prob. 20PCh. 38 - Prob. 21PCh. 38 - Prob. 22PCh. 38 - Prob. 23PCh. 38 - Prob. 24PCh. 38 - Prob. 25PCh. 38 - Prob. 26PCh. 38 - Prob. 27PCh. 38 - Prob. 28PCh. 38 - Prob. 29PCh. 38 - Prob. 30PCh. 38 - Prob. 31PCh. 38 - Prob. 32PCh. 38 - Prob. 33PCh. 38 - Prob. 34PCh. 38 - Prob. 35PCh. 38 - Prob. 36PCh. 38 - Prob. 37PCh. 38 - Prob. 38PCh. 38 - Prob. 39PCh. 38 - Prob. 40PCh. 38 - Prob. 41PCh. 38 - Prob. 42PCh. 38 - Prob. 43PCh. 38 - Prob. 44PCh. 38 - Prob. 45PCh. 38 - Prob. 46PCh. 38 - Prob. 47PCh. 38 - Prob. 48PCh. 38 - Prob. 49PCh. 38 - Prob. 50PCh. 38 - Prob. 51PCh. 38 - Prob. 52PCh. 38 - Prob. 53PCh. 38 - Prob. 54PCh. 38 - Prob. 55PCh. 38 - Prob. 56PCh. 38 - Prob. 57PCh. 38 - Prob. 58PCh. 38 - Prob. 59PCh. 38 - Prob. 60PCh. 38 - Prob. 61PCh. 38 - Prob. 62PCh. 38 - Prob. 63PCh. 38 - Prob. 64PCh. 38 - Prob. 65PCh. 38 - Prob. 66PCh. 38 - Prob. 67PCh. 38 - Prob. 68PCh. 38 - Prob. 69PCh. 38 - Prob. 70PCh. 38 - Prob. 71PCh. 38 - Prob. 72PCh. 38 - Prob. 73PCh. 38 - Prob. 74PCh. 38 - Prob. 75PCh. 38 - Prob. 76P
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- Which statement about the intrinsic carrier concentration in a semiconductor material is FALSE? The intrinsic carrier concentration is exponentially dependent on the inverse of the temperature of the semiconductor material. In an intrinsic semiconductor material, the concentration of electrons in the conduction band is equal to the concentration holes in the valence band. The intrinsic carrier concentration of a semiconductor material at a constant temperature depends on the Fermi energy. The intrinsic Fermi energy is positioned near the center of the bandgap for an intrinsic semiconductor.arrow_forwardSilicon is doped with phosphorus atoms (column V of Mendeleev table) with a concentration of 1018 cm-3 a- What is, at 27 °C, the electron density in doped Si. Use this result to derive the hole density. Which type of semiconductor is obtained? b- Calculate, at 27 °C, the position of the Fermi level EF and plot the band diagram.arrow_forwardConsider the semiconductor crystal at 300 K. Where n, 1.8 x 10^6 cm. a- In a sample containing only 2.5x10^15 cm* ionized donors, where is the Fermi level (E-E;) in e.v ? b- In a sample containing 2x10^15 cm* ionized donors and 9 x 10^14 cm ionized acceptors, where is the Fermi level (Er-E;) in e.v ?arrow_forward
- In the fabrication of a p-type semiconductor, elemental boron is diffused a small distance into a solid crystalline silicon wafer. The boron concentration within the solid silicon determines semiconducting properties of the material. A physical vapor deposition process keeps the concentration of elemental boron at the surface of the wafer equal to 5.0 x 1020 atoms boron/cm3 silicon. In the manufacture of a transistor, it is desired to produce a thin film of silicon doped to a boron concentration of at least 1.7 x 1019 atoms boron/cm3 silicon at a depth of 0.20 microns (µm) from the surface of the silicon wafer. It is desired to achieve this target within a 30-min processing time. The density of solid silicon can be stated as 5.0 x 1022 atoms Si/ cm3 solid. (a) At what temperature must the boron-doping process be operated? It is known that the temperature dependence of the diffusion coefficient of boron (A) in silicon (B) is given by Where Do=0.019 cm2/s and Qo=2.74 x 105…arrow_forwardA silicon p-n junction (ni = 1010 cm3, Na = 1017 cm-3 and Nd = 4 x 1016 cm 3) is biased with an applied voltage Va = -5 V. Calculate the built-in potential, the depletion layer width and the depletion capacitance. Take the temperature as 27°C.arrow_forwardThe Fermi energies of two metals X and Y are 5 eV and 7eV and their Debye temperatures are 170 K and 340 K , respectively. The molar specific heats of these metals volume at low temperatures be written as at constant can (C, )x =rxT + AxT' and (C, ), =7yT+ A,T³ where y and A are constants. Assuming that the thermal effective mass of the electrons in the two metals are same, which of the following is correct? 7 Ax = 8 (b) Y x 7 Ax 1 (a) = - = - 5'Ay 5' A, 8. Y Y x 5 Аx 1 Y x 5 Аx (c) (d) = 8 = - 7' Ay 7' Ay 8. II IIarrow_forward
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