代写VE320 Intro to Semiconductor Devices Summer 2024 – Problem Set 5代做Python语言

VE320 Intro to Semiconductor Devices

Summer 2024 – Problem Set 5

Due: 11:59pm, July 7th

In all problems, assume the temperature is 300K and all are completely ionization.

1.     Define the built-in potential voltage and describe how it maintains thermal equilibrium.

2.   Consider the equation where and and τn0  = 5 × 10−7s. Also let  n ′ = p ′ = ni   = 1015cm −3. Assume very low injection that  δn  ≪ ni. Calculate  R/δn   for a semiconductor which is (a) n-type (n0  ≫ p0), (b) intrinsic (n0  = p0  = ni), and (c) p-type (p0  ≫ n0).

3.   Consider ann-type semiconductor as shown in the figure, doped at  Nd   = 1016cm −3 and with a uniform. excess carrier generation rate equal to g ’ = 1021cm-3s-1. Assume that Dp  =    10cm2/s and τp0  = 10−7s. The electric field is zero. (a) Determine the steady-state

excess minority carrier concentration versus x if the surface recombination velocity at x=0 is (i) s=0, (ii) s=2000cm/s, and (iii) s=∞ . (b) Calculate the excess minority carrier concentration atx=0 for (i) s=0, (ii) s=2000cm/s, and (iii) s=∞ .

Figure 1. Diagram for problem 3

4.   Consider ap1-p2 “isotype” step junction shown in the figure below:

Figure 2. Diagram for problem 4

(a)  Draw the energy band diagram of the junction assuming that the doping is non-degenerate throughout. Assume an energy gap of 1.4eV.

(b) Derive an expression for Vbi that exists across the junction in equilibrium.

5.   AGe diode has ap-side doping of Na  = 5×1016cm-3  and ann-side doping of half that value.

(a)  Calculate depletion widths on both sides of the junction and draw the equilibrium energy level diagram as a function of position. Carefully label all energy levels (Ec, Ev andEf)   and boundaries of the depletion region.

(b) Now apply a reverse voltage 0.1V and repeat part a. Include a sketch of the approximate positions of the quasi-Fermi energies.

6.   Calculate the capacitance and plot c2/1 vs VR  for the following Sin+p junctions:

Na = 1015cm-3

(a)  Reverse bias voltage = 1V; (b) reverse bias voltage = 5V.

(For n+p junctions,  Nd    ≫  Na.  Use a suitable approximation in your calculation.)

7.   In the diagram below (the material is Si) :

Figure 3. Diagram for problem 7

(a)  Is the diode under equilibrium or forward biased or reverse biased? If biased, what is the bias voltage?

(b) Determine the built-in potential of the diode under equilibrium.

(c)  Determine Na  and Nd.