(a) A certain npn BJT has an emitter area of (10 m) 3 (20 m), and its base and emitter doping concentrations are NAB 5 1017/cm3 and NDE 5 1019/cm3 . Assuming Dp 5 1.8 cm2 /s, Dn 5 18 cm2 /s, WB 5 WE 5...

(a) A certain npn BJT has an emitter area of (10 m) 3 (20 m), and its base and emitter doping concentrations are NAB 5 1017/cm3 and NDE 5 1019/cm3 . Assuming Dp 5 1.8 cm2 /s, Dn 5 18 cm2 /s, WB 5 WE 5 1 m, and n 5 150 ns, fi nd Is and F. (b) If VBE 5 700 mV, fi nd IC and IB. (c) What portion of IB is due to holes diffusing from base to emitter, and what portion is due to electrons recombining inside the base?