Question

this is a problem of semiconductor device and fundamentals.

Problem 4: pn Junction Current Distributions Consider a Si pn step junction diode maintained at room temperature, with p-side and n-side dopant concentrations NA 1016 cm3 and Np-2x1016 cm3, respectively. (You may assume that each side is uncompensated.) The minority carrier recombination lifetimes are τ,-10-6 s and τ,-10-7 s on the p-side and n-side, respectively a) Calculate the minority carrier densities at the edges of the depletion region when the applied bias is (kTiq) In100.48V b) For the applied bias in part (a), derive expressions for the minority-carrier diffusion current in the quasi-neutral regions. Sketch the electron and hole current density components (JN and Jp, respectively) as a function of distance on both sides of the junction. Indicate the values of JN and Jp in the depletion region, as well as the total current density J Hint: To determine the minority carrier diffusion lengths, use the values of carrier mobilities from Figure 3.5a in Pierret c) Calculate the location of the plane (i.e. the value ofx, assuming that x = 0 at the metallurgical junction) at which the electron and hole current densities are equal in magnitude, for the applied bias of part (a).

Answer 1

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VA Nt' CT. SX10 16 2지 0 Vi^) 2ο 25χρ NA 2-3 for inort 2-х prers.coos

minor irtų Coxnex Diffusion ent dons< be (3p hou) Th hole Concant -う( VA

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Hieh<ue noni ly Carrier tens tiei at the de-Ploti on of the te cta platien r*^en » of Na. ni no NA if ni is not aver