Transistor Structure Overview

A transistor is a fundamental semiconductor device used to amplify or switch electronic signals and electrical power. Its basic structure involves semiconductor materials.

Semiconductor Junctions in Transistors

Transistors are typically constructed using semiconductor materials like silicon or germanium. The core operational principle relies on the behaviour of charge carriers across junctions formed between different types of semiconductor materials (p-type and n-type).

• A transistor is formed by joining three semiconductor layers.
• This arrangement creates two distinct p-n junctions within the device.
• For example, an NPN transistor consists of a p-type layer sandwiched between two n-type layers (creating two N-P junctions).
• Similarly, a PNP transistor has an n-type layer sandwiched between two p-type layers (creating two P-N junctions).

Therefore, a transistor fundamentally consists of two p-n junctions.