The carrier mobility decreases with doping because of what reason? (a) impurity scattering (b) phonon scattering (c) the

[answerhappygod]

The carrier mobility decreases with doping because of
what reason?
(a) impurity scattering
(b) phonon scattering
(c) the depletion region formation
(d) surface scattering
(e) none of the above
The gold doping in base region
of BJT increases its switching speed because of
what?
(a) it reduces base/collector junction capacitance
(b) it reduces emitter/base junction capacitance
(c) it reduces the lifetime of injected minority carriers
(d) (a) and (b) only
e) none of the above