ELE533 Bipolar Devices

Mid Term Exam
October 25, 2005

  1. An abrupt Si p-n junction has the following properties at 300 oK:

    Property P side N side Unit
    Doping NA = 1018 ND = 1016 cm-3
    Lifetime tn = 0.1 tp = 10 uS
    Mobility un = 250 un = 1200 cm2/V-s
    Mobility up = 100 up = 350 cm2/V-s

    Area = 10-4 cm-2
    The width of the N neutral region WN = 3 microns.
    The width of the P neutral region WP = 2 microns.

    1. What is the zero bias junction capacitance for this diode?

    2. If the forward current is 1 mA, what is the diffusion capacitance?