Why the base region of a transistor is lightly doped?

Why the base region of a transistor is lightly doped?

If base is made thick and highly doped, majority carriers will combine with the other carriers within the base and only few is collected by the collector which leads to small output collector current. Thus in order to have large output collector current, base is made thin and lightly doped.

Which region of the BJT is lightly doped?

The base region of a BJT transistor is very thin and is lightly doped with current carriers. It is the region of a transistor which has opposite polarity charge carriers from the emitter and the collector regions.

Which region is heavily doped in BJT?

The emitter region is the most heavily doped area of the transistor. The emitter contains the largest amount of charge carriers out of all regions in the transistor.

How is base of the transistor is doped?

In most transistors, emitter is heavily doped. Its job is to emit or inject electrons into the base. These bases are lightly doped and very thin, it passes most of the emitter-injected electrons on to the collector. The collector is so named because it collects electrons from base.

Why is the base region lightly doped as compared to emitter and collector regions?

The width of the region depends upon their doping. The base region is lightly doped so that width of the base is less. Collector region of a transistor is highly doped so collector region has more width than other two.

Which of the following in the BJT is the heavily doped region emitter base collector all the regions are equally doped?

Transistor consists of three main regions i.e. Emitter, Base, and Collector. Emitter (E): It provides majority charge carriers by which current flows in the transistor. Therefore the emitter semiconductor is heavily doped.

Which terminal of a BJT is highly doped?

What are the shallow doped areas in BJT?

These “shallow doped” areas are the base and the collector. A BJT works by the carriers from the emitter “overwhelming” the amount of (opposite) carriers (in case of an NPN: holes) in the base region. Also, the base region is narrow. This makes the chance that a carrier originating from the emitter recombines in the base, small.

What is the role of the base region in a BJT?

Role of Base Region of a BJT Transistor The role of the base region is to function as the trigger for a larger emitter-to-collector current. When the base current receives sufficient current, a larger current then flows from the emitter to the collector.

Why the base is lightly doped in BJT or in transistor?

Collector region of a transistor is highly doped so collector region has more width than other two. Hope you understand clearly why the base is lightly doped in bjt or in the transistor. For good amplification process, we required less base current and more collector current So we try to reduce base current by less doping of base region.

What is the effect of low doping on BJT collector?

However a low doping level on the collector does increase the size of the depletion region and this increases the maximum collector-base voltage. Also it is much easier to manufacture a BJT with a shallow doped collector, then the base and emitter regions are doped “on top of” the doping of the collector.