1. Define the majority carrier concentration in an n-type Si semiconductor in terms of the conduction...
Define the majority carrier concentration in an n-type Si semiconductor in terms of the conduction band edge energy E, and the Fermi energy E. 1. 2 marks Find an expression for Ee -Ef, i.e, the difference between the conduction band edge energy and the Fermi energy in terms of the donor concentration ND. 4 marks Determine the concentration of donor impurity atoms that must be added to silicon so that Ec- E0.2 eV. 3 marks
Silicon at at T-300 K contains acceptor atoms at a concentration of Na-5x10A15 cmA-3. Donor atoms are added forming an n type compensated(counter doped) semiconductor such that the fermi level is 0.215 eV below the conduction band edge 4. a. What concentration of donor atoms were added. b. What were the concentration of holes and electrons before the silicon was counterdoped c. What are the electron and hole concentrations after the silicon was counter doped. Silicon at at T-300 K...
Silicon at at T-300 K contains acceptor atoms at a concentration of Na-5x10A15 cmA-3. Donor atoms are added forming an n type compensated(counter doped) semiconductor such that the fermi level is 0.215 eV below the conduction band edge 4. a. What concentration of donor atoms were added. b. What were the concentration of holes and electrons before the silicon was counterdoped c. What are the electron and hole concentrations after the silicon was counter doped. Silicon at at T-300 K...
(2) In a semiconductor with an energy gap Eg between the valence and the conduction bands we can take Ef (the Fermi energy) to be halfway between the bands (see figure below): Conduction band Energy gap Eg Valence band Semiconductor a. Show that for a typical semiconductor or insulator at room temperature the Fermi- Dirac factor is approximately equal to exp(-E 2kBT). (Typical Eg for semi-conductors ranges from about 0.5eV to 6eV at T-293K.) b. In heavily doped n-type silicon,...
Problem 1 (25 points) Si at T = 300K contains donor impurity atoms at a density of 5x 10'6cm and acceptor impurity atoms at a density of 2x106 cm-3 . Assume ni 1.5x10'0cm-3, kT-0.026eV a) (5 points) Is the semiconductor n type or p type? b) (10 points) Determine n, and Po c) (10 points) Draw the energy band diagram (Ec, Ev, EFi, Ef) and indicate the position of Ef with respect to Epi Problem 1 (25 points) Si at...
9.2. Consider an As (arsenic) substitutional impurity in a Si crystal. From Fig. 8.6 we see that an electron bound to this atom has an energy of Ec-0.054 eV. Using the simple Fermi-Dirac distribution function of (9.6) to calculate the probability that an electron is in the bound state of this atom if the Fermi level EF is located at: (a) Ef = Ec - 0.200 eV, (b) Ep = Ec - 0.100 eV, (c) Ep = Ec, (d) Ep...
An ideal metal-semiconductor (M-S) junction is formed on the n-type Si semiconductor that is uniformly doped with a donor impurity (phosphorus) concentration of 1016 cm. The metal work function is 4.5 eV, and the Si electron affinity is 4 eV. Assuming that this M-S junction is at 300K, give your best answers to the following questions. (50 points) (a) At thermal equilibrium, draw the energy band diagram including meaningful parameters (energy barriers, energy levels, depletion width, etc.). (b) Calculate the...
In a semiconductor it can be shown that the product of the electron and hole densities is the square of the intrinsic density, i.e., pm n. Find the equilibrium electron (n) and hole (p) concentrations and the location of the Fermi level (EF) referenced to the conduction band (Ec) or valence band (Ev) in Si at 27°C if the Si contains the following concentrations of shallow dopant atoms: a) 1x1016 cm-3 boron atoms b) 3x1016 cm-3 arsenic atoms and 2.9x1016...
Si has 6 equivalent conduction bands. Through additional engineering we will learn later on, we can make the two conduction band minima located on the [001] axis move down compared to the four other conduction bands, by a small amount AEc. 1. Write down an expression of electron concentration in terms of Fermi level Ef, conduction band level Ec, which is the Ec of the lowest conduction band minima, the transverse and longitudinal effective masses mi and mt, temperature T...
Draw the energy band diagram at equilibrium for the p+ /n/p semiconductor heterostructure (p+ indicates a p-type semiconductor which is heavily doped, i.e., more heavily doped than p). You should indicate Ec (conduction band), Ev (valence band), Ei (intrinsic Fermi level), and Ef (Fermi level) throughout the device structure. show your work (i.e., you should start from the diagram of individual material pieces). State any reason for your drawing.