Use this information to answer Question 1-6:

Consider a silicon npn bipolar junction transistor uniformly doped and biased in the forward active mode. The doping densities are N _DE  = 5 x 10 ¹⁷  cm ^-3  , N _AB  = 1 x 10 ¹⁶  cm ^-3  and N _DC  = 1 x 10 ¹⁵  cm in the emitter, base and collection regions, respectively.

1. Calculate the values of equilibrium minority carrier concentration in the emitter region, p _EO  .
Give your answer in unit of cm ^-3  .

2. Calculate the values of equilibrium minority carrier concentration in the base region, n _B0  ,

Give your answer in unit of cm ^-3  .

3. Calculate the values of equilibrium minority carrier concentration in the collector region, p _C0  , give your answer in unit of cm ^-3  .

4. For a forward bias on the base-emitter junction, V _BE  = 0.625 V and a large reverse bias on the base-collector junction, calculate the electron concentration at the edge of the base region toward the emitter side, n _B  (0). Give your answer in unit of cm ^-3  .

5. For the same biasing condition as given above, calculate the electron concentration at the edge of the base region toward the collector side, n _B  (x _B  ). Give your answer in unit of cm ^-3  .

6. The natural base region width is x _B  = 0.6µm, which may be considered small enough to ignore any recommendation within the base region. Calculate the electron current in the base region, J . Given your answer in unit o A/cm ²  .