Question

Given below are two statements :
Statement I : In a typical transistor, all three regions emitter, base and collector have same doping level.
Statement II : In a transistor, collector is the thickest and base is the thinnest segment.
In the light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement I and Statement II are incorrect
• B. Statement I is correct but Statement II is incorrect
• C. Both Statement I and Statement II are correct
• D. Statement I is incorrect but Statement II is correct

Hint:

In a transistor, the doping levels and the thickness of each region serve specific purposes related to current control and heat dissipation.

Answer 1

The Correct Option is D

To solve the question, let's analyze both statements given in the context of a typical transistor's structure: 

1. Statement I: In a typical transistor, all three regions emitter, base, and collector have the same doping level.
   • This statement is incorrect.
   • In a typical transistor, the doping levels of the emitter, base, and collector are intentionally made different to optimize their respective functions:
     • The emitter is heavily doped so it can effectively inject carriers (electrons or holes) into the base region.
     • The base is lightly doped and very thin compared to the other regions, allowing it to efficiently facilitate carrier flow while minimizing recombination.
     • The collector is moderately doped and typically the thickest region, allowing it to collect carriers from the base.
2. Statement II: In a transistor, collector is the thickest and base is the thinnest segment.
   • This statement is correct.
   • The collector needs to be thick to handle heat dissipation and high reverse bias voltages. The base is thin to allow carriers to cross swiftly from the emitter to the collector with minimal recombination.

Given the analysis above:

• Statement I is incorrect because the regions have different doping levels for optimal performance.
• Statement II is correct as it accurately describes the structural characteristics of a transistor.

Conclusion: The most appropriate answer is "Statement I is incorrect but Statement II is correct."