7.4.2. Doping Concentrations

Try these first

1. 1.

   What type of doping is used for the emitter in a BJT?

   Hint

   Think about the charge carriers.

2. 2.

   Define a BJT.

   Hint

   Consider how it operates with two different types of charge carriers.

3. 3.

   What is the primary purpose of doping a BJT?

   • To create a physical barrier
   • To change its electrical properties
   • To increase the size

   Hint

   Think about what doping does to a semiconductor's behavior.

4. 4.

   True or False: Minority carriers in a p-type material are holes.

   • True
   • False

   Hint

   Consider the definitions of minority and majority carriers.

5. 5.

   Given a BJT with a specific emitter doping concentration and forward bias voltage, derive the expected emitter and base currents.

   Hint

   Consider the roles of both the thermal voltage and the doping concentrations.

6. 6.

   Explain how varying the doping concentration in the base might affect the overall current gain of a BJT.

   Hint

   Think about how charge carriers interact in different materials.