20111ee2_1_2011_EE2_HW4

20111ee2_1_2011_EE2_HW4 - (separate the components due to...

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Physics for Electrical Engineers P r o f . B . J a l a l i E E 2 Homework #4 Due: Feb. 24 th , 2011, 4:00pm Consider a long Si p + -n junction with a highly doped p-side N A =1 x 10 18 cm -3 and a regular doped n-side, N D =1 x 10 15 cm -3 ), τ n =1 μ s and D n =10 cm 2 /s in the neutral p-side, τ p =1 ms, D p =15 cm 2 /s in the neutral n-side, Area=5 x 10 -4 cm -2 . Calculate the following (assume ideal characteristics, T=300 K): 1) For a forward bias of V F =0.7 V, calculate a. I p /I (ratio of current due to hole injection) and I n /I (ratio of current due to electron injection) at the edge of the depletion regions; b. Calculate the dynamic resistance (dV/dI); c. Total excess minority carrier charge in the quasi-neutral regions; d. Diffusion Capacitance due to the excess minority charge calculated in part (c)
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Unformatted text preview: (separate the components due to electrons and holes); 2) Repeat the above for a reverse bias of V R =-5 V. 3) What’s the cut-off frequency at V F =0.7 V and V R =-5 V (the maximum frequency at which this diode can perform small-signal AC modulation), respectively? 4) How does the total current change if the n-side doping is doubled (at V F =0.7 V and V R =-5 V, respectively). Assume all other parameters remain the same. 5) How does the total current change if the p-side doping is doubled (at V F =0.7 V and V R =-5 V, respectively). Assume all other parameters remain the same....
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This note was uploaded on 10/07/2011 for the course EE 2 taught by Professor Vis during the Spring '07 term at UCLA.

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