| 
Physics of Semiconductor Devices  | 
| 
 | 
Bipolar transistor(a) Draw a pnp bipolar transistor showing the emitter, collector, and base contacts. (b) Draw the minority carrier concentrations for a pnp transistor in the saturation mode (both pn-juctions are forward biased). (c) What is a heterojunction bipolar transistor and what are they used for?  |