Ele533 Bipolar Devices
Diffusion Capacitance

An abrupt Si p-n junction has the following properties at 300 oK:
Property P side n side Unit
Doping NA = 1015 ND = 1017 cm-3
Lifetime tn = 10 tp = 0.1 uS
Mobility un = 1300 up = 700 cm2/V-s
Mobility up = 450 un = 250 cm2/V-s
A = 10-4 cm-2

Approximately what is the diffusion capacitance for this diode at a forward current of
1 mA? The contact on the p side is 2 microns away from the metallurgical junction.

What is the incremental resistance?