Why Silicon as a semiconductor chip?

A semiconductor is a material whose electrical conductivity at room temperature is between that of a conductor and an insulator. Like copper wire in everyday life, aluminum wire is a conductor, and rubber is an insulator. From the point of view of conductivity: semiconductor refers to a conductivity controllable, ranging from insulator to conductor.

In the early days of semiconductor chips, silicon was not the main player, germanium was. The first transistor was a germanium based transistor and the first integrated circuit chip was a germanium chip.

However, germanium has some very difficult problems, such as many interface defects in semiconductors, poor thermal stability, and insufficient density of oxides. Moreover, germanium is a rare element, the content in the Earth’s crust is only 7 parts per million, and the distribution of germanium ore is also very dispersed. It is precisely because germanium is very rare, the distribution is not concentrated, resulting in the high cost of germanium raw materials; Things are rare, raw material costs are high, and germanium transistors are not cheap anywhere, so germanium transistors are difficult to mass produce.

So, the researchers, the focus of the study jumped up one level, looking at silicon. It can be said that all the congenital shortcomings of germanium are the congenital advantages of silicon.

1, silicon is the second most abundant element after oxygen, but you can hardly find silicon in nature, its most common compounds are silica and silicates. Silica is one of the main components of sand. In addition, feldspar, granite, quartz and other compounds are based on silicon-oxygen compounds.

2. The thermal stability of silicon is good, with a dense, high dielectric constant oxide, can easily prepare a silicon-silicon oxide interface with few interface defects.

3. Silicon oxide is insoluble in water (germanium oxide is insoluble in water) and insoluble in most acids, which is simply the corrosion printing technology of printed circuit boards. The combined product is the integrated circuit planar process that continues to this day.