What Is a Planar Transistor?

A transistor fabricated using a planar process is called a planar transistor.

The internal structure of the planar transistor is shown in Figure 1. Its central organization also includes two

1. There is always a protective silicon dioxide film on the crystal surface, so the pn junction can be protected from pollution and harmful atmosphere, which greatly improves the reliability, stability and parameter uniformity of the transistor;

2. The reverse current is extremely small, which is only a few nanoamperes. For example, 3 volts and 100 milliamps can be used for 10,000 low-power planar tubes, which can greatly reduce the weight of the power supply. This is of great significance for space navigation and rocket electronics;

3. Since the pn junction is not exposed to the outside and the surface is very stable, the noise is also smaller than other types of transistors;

4. Using the planar structure and technology, it is possible to produce very delicate and complicated electrode patterns, thus opening up a broad way for the development of transistors to high frequency and high power. ^[1]