Why use high purity silicon powder to make semiconductor materials
Early semiconductor materials were made from germanium because the purification technology for silicon was not mature. The first integrated circuits were built on germanium. There are several possible reasons for using high-purity silicon powder to make semiconductor materials. The Earth's crust contains a high amount of silicon. Based on our current use of semiconductor silicon, if we still use germanium, there might not be much germanium left on the planet (I don't have an exact count).
The interface between silicon and silica. The interfacial properties of high purity silicon powders are good. Compared with the interface of the corresponding oxide layer of other semiconductor materials, the interface of silicon and silica is perfect. With the development of technology, the control of interface defects is getting better and better. For example, after clean room modification, the impact of defects has been low. At the same time, when impurity is injected, silica can act as a shielding layer, effectively blocking phosphorus, boron and other impurities. Second, high-purity silicon powder is a very stable insulator material (its energy gap is about 9eV, I don't know if I remember correctly), and germanium dioxide is not only unstable at high temperatures, but also soluble in water, while silicon dioxide does not have such a problem at all; The large energy gap of silica will make the leakage rheology small (of course, if the oxide layer is too thin, the leakage current will increase).
Compared with germanium, high purity silicon powder has a larger gap, so it can withstand higher operating temperature and a wider range of impurities doping. Silicon also has a higher breakdown voltage. Previous semiconductor devices are made of germanium, mature technology, faster switching response. But it costs a lot of money. The capitalists chose silicon, and many scientists began to make breakthroughs in silicon. Of course, this has to do with many good properties of silicon itself, such as large reserves and stable performance. Another advantage is that silica is a natural insulator and can be used directly as an intermediate layer after heat treatment.
The high purity silicon powder with 99% (2N), 99.9% (3N), 99.99% (4N) silicon content, oxygen, carbon, phosphorus, sulfur and metal impurity content are very low, which can meet the needs of the industrial process with high impurity requirements, and fill the gap in the field of high purity industrial silicon powder in China. Aeronautical/automotive aluminum alloys, titanium alloys, copper alloys, high performance silicon nitride and carbon...
In the world, the production of high purity and high purity silicon powder materials is still dominated by the United States, Germany, Japan and South Korea. With the encouragement of government policies and a large amount of financial assistance, relying on self-built power plants, preferential electricity prices, fiscal and tax subsidies and other policy support, we paid equal attention to technological transformation and capacity expansion.
