for a non-uniformly doped base(upgraded doped in log scale) BJT
(NPN),what's the closed form eqations for calculating:
1.the depletion width between base-collector and base-emitter 
2.electron mobility in a graded doped base
3. current-voltage relationship in the base
thank you very much

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Clarification of Question by fakefate-ga on 18 Nov 2004 21:37 PST

equations with REASONABLE assumptions are acceptable.

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Clarification of Question by fakefate-ga on 19 Nov 2004 13:11 PST

type on the first sentence, it should be (graded dope...) instead of
(upgraded doped...)
thanks