Cheaper and purer silicon carbide explored

Researchers with the Semiconductor Materials Research Division at Linkoping University (LiU) in Sweden say it is possible to produce cheaper and purer silicon carbide.

Silicon carbide is an electronic material capable of tolerating large amounts of power, high frequencies, and high temperatures. It has applications in tougher uses such as electric cars. However, the production of silicon carbide is time consuming and costly. Compared to the low price of silicon, the cost factor has slowed the breakthrough for the material.

The Semiconductor Materials Research Division at LiU uses epitaxial growth to fabricate silicon carbide. According to the scientists there, simultaneously introducing chlorine, silane gas and carbon source in the form of light hydrocarbons accelerate production and reduce the costs.

With the traditional epitaxial method, silane gas vapour forms the unstable compound SiH2. With chlorine gas, the process forms a more stable compound, SiCL2. This allows the process to speed up without the risk of silicon drops forming and ruining the surface. The carbon and silicon bond only on the crystal surface, and the chlorine breaks off to form hydrogen chloride gas (HCl). This needs to be dealt with so rust doesn’t form.

Forming the “thick” layers (0.2mm) sought after normally takes two days. With chlorine in the process, this can be done in an afternoon without degrading the quality of the material. This means the cost of heat energy, gas, and wear is one-twentieth what it was before.

The chlorine method has met with some resistance from manufacturers, who are worried about the HCl as a by-product. However, Cree has implemented the method, as has LG Electronics.


This story was originally posted in Electronics News.


Linkoping University