Physics of Semiconductor Devices

Sze problems 5.3, 5.4 and 5.5

A silicon p-n-p transistor has impurity concentrations of 500000000000000000 cm^-3, 7.0E+16 cm^-3, and 1.0E+16 cm^-3 in the emitter, base and collector, respecitvely. The base width is 1.0 μm, and the device cross-sectional area is 0.2 mm². When the emitter-base junction is forward biased to 0.5 V and the base-collector junction is reverse biased to 5 V, calculate the neutral base width and the minority carrier concentration at the emitter-base junction.

The diffusion constants of the minority carriers in the emitter, base, and collector are 59 cm²/s, 42 cm²/s, and 118 cm²/s respectively; and the corresponding lifetimes are 10^-8 s, 10^-7 s, and 10^-6 s. Find the current components I_Ep, I_Cp, I_En, I_Cn, and I_BB.

Source: Sze.

Find the terminal currents I_E, I_C, and I_B of the transistor; calculate the emitter efficiency, base transport factor, common-base current gain, and common-emitter current gain; and comment on how the emitter efficiency and base transport factor can be improved.