If diamonds can replace silicon, the basic material of chips, sows can climb trees. In the history of semiconductor development, germanium semiconductor was very popular at first, but it was quickly defeated by silicon semiconductor. Finally, silicon dominates the semiconductor kingdom, and germanium semiconductors exist only in a few fields. To tell the truth, although diamond can capture women's hearts, in the eyes of people in the semiconductor industry, its commercial value is not even as good as germanium. Below, I will analyze the reasons one by one.

In order to replace silicon, the element content must be rich. Easy-to-mine silicon is called "God's wealth to mankind". One of the reasons is that it accounts for 26.4% of the total mass of the earth's crust and is the second richest element after oxygen. Grab a handful of sand and pick up a stone, which contains a lot of silicon oxide-silicon dioxide.

In contrast, the content of germanium is only 65438+7/ 1000000, which is very rare, and there is almost no enriched germanium ore, resulting in the mining cost of germanium being several hundred times that of silicon, and its commercial value is very low. Although there are concentrated diamond mines, the content of diamonds is too small. In 20 15, the global demand for semiconductor-grade polysilicon exceeded 60,000 tons, which is increasing every year. If you want to replace silicon, where can you find more than 60 thousand tons of diamond every year?

It is difficult to purify diamonds. Diamond contains more or less impurities. It is difficult to remove these impurities with current technology. The purification of silicon is much easier. Silicon dioxide is melted in an electric arc furnace, reduced with carbon or graphite to obtain industrial silicon (also called "Metal Precious") with silicon content of 98.5%, and then crushed into fine powder, which reacts with liquid hydrogen chloride (not hydrochloric acid, but aqueous solution of hydrogen chloride) at about 300 degrees Celsius to generate trichlorosilane, and then purified by distillation to obtain high purity.

A single crystal silicon rod with a diameter of 12 inch (the largest at present) is about 2 meters high, weighs about 350 kilograms, and has a purity of 99.99999999%, which is equivalent to 1 0 billion silicon atoms, and allows1impurity atoms to exist. It can be seen from the above process that the purification of silicon is a series of continuous redox reactions. In order to have chemical reaction, the chemical properties of elements are relatively active, but the main component of diamond is carbon, and the chemical properties of carbon are far less active than that of silicon, so it is difficult to carry out redox reaction to remove impurities and improve purity. Diamond processing is difficult. After purification is difficult, the processing problem is the biggest problem. Before making chips, monocrystalline silicon rods need to be sliced. Although the hardness of silicon is high, it can be cut by diamond, the hardest substance in nature.

However, it will be a difficult problem to use diamond as chip matrix material. Cutting diamonds with diamonds is inefficient and costly, and only artificial substances with higher hardness can be used. At present, the artificial substance with the highest hardness is carbyne, which is 40 times harder than diamond, but it is still in the experimental stage and has not yet reached the stage of large-scale commercialization. There is no good solution to how to slice diamonds.

Even if carbyne can be successfully commercialized and diamonds can be sliced in the near future, the real question is: how to make insulating films? It is very convenient to make insulating film on silicon wafer. When the silicon wafer is placed in a high-temperature steam environment of about 900 degrees Celsius, the silicon wafer will have a thermal oxidation reaction with oxygen, and a silicon oxide film-silicon dioxide (the main component of glass) will grow on the surface, then photoresist will be coated and etched, and then the chip can be obtained by other processes and materials.

Silicon oxide film has the characteristics of no moisture absorption, acid and alkali resistance, good thermal conductivity, stable optical performance and good insulation performance (feeling abstract, think about the characteristics of glass), which is the premise of chip manufacturing. Silicon oxide film can be easily obtained through this matrix material. It is precisely because the silicon oxide film is so important, so easy to obtain and rich in silicon that silicon is called "the wealth given by God to mankind".

If diamond is used as the chip matrix, where does the oxide film come from? Diamond itself is pure carbon, and its oxide is carbon dioxide, which is gaseous at room temperature and plays an insulating role? That's impossible. As soon as it was formed, people rushed into the air and enjoyed themselves. Use other oxides? Experimental verification, technological process research and development, and equipment transformation cost a lot of money, but they may not be successful.

In a word, using diamond as chip matrix material is not only low in content, but also extremely difficult to process and has extremely low commercial value. Because of these shortcomings, it is impossible to replace silicon in the chip industry. The original answer, processing must be checked.