IC Substrate - Detailed explanation of semiconductor materials in the PCB circuit board industry

1.Semiconductor definition:
A semiconductor is a material, which refers to a material that has conductivity between a conductor and an insulator at room temperature. Semiconductors play an important role in all electronics manufacturing industries. For example, diodes are devices made of semiconductors. The conductivity of a semiconductor can vary according to its external conditions, and can change from completely non-conductive to completely conductive. So it can be used to make electronic components in different states. Whether it is technology, economic benefits or practical value, semiconductors are one of the few good materials. Among semiconductor materials such as silicon-silicon semiconductors, germanium semiconductors, and gallium arsenide semiconductors, silicon semiconductors are the most widely used in electronic manufacturing and are also the most widely used semiconductor materials in commerce. Compared with insulators and conductors, semiconductors have a short history. According to materials, semiconductor materials were recognized by academia in the 1930s and truly entered life.

Since we are going to introduce semiconductors, then we have to introduce an appropriate term "intrinsic semiconductor" for so long. Intrinsic semiconductors are semiconductors without any impurities or lattice defects. However, intrinsic semiconductors have relatively high resistivity and little practical value, so they are rarely used in commercial applications.
semiconductors

2. Semiconductor classification:
As we all know, there are many materials for insulators and conductors, so there is no shortage of semiconductor materials. Semiconductor materials are generally classified by chemical composition, one is elemental semiconductor, and the other is compound semiconductor. The most commonly used elemental semiconductors are germanium semiconductors and pair semiconductors. Compound semiconductors are widely used, such as gallium arsenide semiconductors, gallium phosphide semiconductors, and cadmium sulfide semiconductors.

3. History of semiconductors:
In fact, the discovery of semiconductors can be traced back to 1833, when silver sulfide was discovered in Faraday, England, which can reduce its own resistance as the temperature rises. This is the first time that a semiconductor phenomenon has been discovered. Later, in 1839, Beclere of France discovered a phenomenon that under the care of a child, the junction formed by the contact between a semiconductor and an electrolyte can generate a voltage. This phenomenon is also called the photovoltaic effect. In 1873, another scientist from the United Kingdom, Smith, discovered another characteristic of semiconductors, the photoconductivity effect. The detailed development process is not given as an example. However, there is a question, that is why the definition of semiconductor has been recognized by academia for so long? For details on this issue, you need to read the material "The coming of Materials Science".

4. Five characteristics of semiconductors:
Semiconductors have five characteristics: doping, heat sensitivity, photosensitive, negative resistivity temperature characteristics and rectification characteristics.

5. The application of semiconductors in integrated circuits;
The basis of integrated circuits is transistors, and the basis of transistors is semiconductors, so the basis of integrated circuits is semiconductors. Among them, the most common and widely used semiconductor is silicon semiconductor. So why does silicon semiconductor become the darling of integrated circuits? We can consider several points separately.

The first point: Anyone who knows chemistry knows that the four most abundant elements on earth are oxygen, silicon, aluminum and iron. In this order, we know that silicon is the second most abundant element on earth. Silicon is the most abundant in the earth's crust, which means that the cost of extracting silicon semiconductor raw materials is very low.
The second point: The impurity concentration in silicon semiconductors is easy to manually control, and it is convenient to obtain components that meet the requirements, that is, transistors. And the silicon on the surface is oxidized, and a very stable oxide film, silicon dioxide, will be formed as an insulating film.

Third, in terms of technology, silicon semiconductors are easier to achieve oxidation and photolithography, and their performance is more controllable than other types.