Tutorial2

Tutorial 2

  1. Find the room temperature resistivity of n-type silicon doped with 1016 phosphorous atoms per cm3. The mobility of electron at this doping level at 300 K is 1300 cm2/V-s.
  2. Minority carriers (holes) are injected into a homogeneous n-type semiconductor sample at one point. An electric field of 50 V/cm is applied across the sample and the field moves the minority carriers a distance of 1 cm in 100 µs. Find the drift velocity and mobility of the minority carriers.
  3. Silicon bar 0.1 cm long and 100 µm2 in cross sectional area is doped with 1017 /cm3 Antimony (Shown in figure below). Find the current with 10V applied as shown in figure. The mobility of electron in this bar is 700 cm2/ V –s
  1. How long time does it take for average electron to drift 1 µm in pure Silicon at an electric field of 100 V/cm. The mobility of electron is 1350 cm2/V-s.
  2. Electrons in some conductor have a density of 1020 / cm3 and mobility of 800 cm2/V-s. If a uniform electric field of 1V/cm exists across the conductor, determine the electron current density.
  3. Electrons in some conductor have a density of 1019 / cm3 and mobility of 900cm2/V-s. If a uniform electric field of 1.5V/cm exists across the conductor, determine the electron current density.
  4. The specific density of the tungsten is 18.8 g/cm3 and its atomic weight is 184. Assume that there are two free electrons per atom. Calculate the concentration of free electrons.
  5. Compute the mobility of the free electrons in aluminium for which the density is 2.70g/cm3. The resistivity is 3.44 * 10 -6 ohm cm. Assume that aluminium has three valence electrons per atom.

References:

Q1 Q2 – “Physics and Technology of Semiconductor Devices” by S M Sze

Q3 Q4– “Solid State Electronic Devices” by Ben Streetman and Sanjay Banerjee

Q5 Q6 Q7 Q8 – “ Integrated Electronics” by Millman, Halkias and Parikh