An Introductory Guide to Semiconductors

Semiconductors are key components used in the electronics industry. They conduct electricity under certain conditions but do not conduct it under others. Semiconductors are insulators that become conductors when their temperature is raised above a certain threshold. This means that they can control the flow of electrical current through them, making them uniquely useful components in many different types of electronics.

A semiconductor diode is a basic semiconductor component. It was the first semiconductor-based electronic device available.

In simple terms, a diode is a semiconductor that has a P-N junction connected to two electrical terminals. The P-N junction is an elementary building block used in most semiconductor devices, including diodes and transistors. It’s essentially a boundary or interface between two types of semiconductor material – P-type, and N-type – which are created by implanting impurities.

Semiconductor diodes feature asymmetric characteristics. They have high resistance to current flow in one direction and low resistance in the other direction. The non-linear current-voltage characteristics of semiconductor diodes can be further adapted using different materials and by adding impurities into these materials (a process referred to as doping) to enable them to perform different functions.

The most common function of a semiconductor diode is to allow an electric current to pass in one direction (forward) while blocking current in the opposite direction (reverse). They are commonly used in electrical circuits, such as in a diode bridge to rectify a signal to convert AC to DC.

In addition, semiconductor diodes can also be used to conduct electricity only if a certain threshold voltage is present in the forward direction (forward biased). The voltage drop across a forward-biased diode will vary only slightly with the current, affected by temperature. This effect means that a semiconductor diode can also be used as a temperature sensor.

Strictly speaking, a semiconductor is not a component but a material that has a conductivity between that of conductors and insulators. Many forms naturally exist due to their chemical makeup.

Silicon (Si) is the dominant material used in the industry today, but other materials can be used such as germanium (Ge) or arsenide (GaAs). Semiconductors including silicon have unique electrical properties associated with their atomic structure.

When a semiconductor is composed of small crystals of crystalline compounds, it is referred to as a microcrystalline or amorphous semiconductor material. The above materials are all examples of amorphous semiconductors.

Discrete semiconductors are supplied in packages which protect the semiconductor material. These packages are usually made from materials such as plastic, ceramic, glass, or metal. The package provides protection and holds the contact pins, leads or pads used to connect the device to external circuits. The packaging is also important in dissipating heat produced by the device.

There is a wide range of different semiconductor packaging types available, and the best option will depend largely on factors including size, power dissipation, and lead or pad count.