Our Products

Trichlorosilane (TCS)

Introduction

Trichlorosilane (SiHCl₃is a colorless liquid containing silicon, hydrogen, and chlorine. It is the key intermediate compound used to produce extremely pure polysilicon, from which computer chips and solar cells are made. Interestingly, the volume of Trichlorosilane required needed to produce polysilicon has a. ratio is 6.25 to 1. In other words, 6.25 MT of Trichlorosilane is required to produce 1 MT of polysilicon.

The key difference between solar grade and industrial grade polysilicon is the purity requirement. The purity requirement for industrial grade polysilicon is the highest and typically 99.999...% (in nine 13s) pure or more, while solar grade polysilicon tends to be at least 99.999...% (in six 9s) pure.

In 2000, the semiconductor industry consumed over 90% of the world's silicon supply while the solar industry consumed approximately 10%. In 2006, the solar industry consumed more than 50% of the world's available supply of polysilicon for the first time ever. This historic shift illustrates the growing size and importance of the solar industry.

The barrier to entry in the solar business varies depending where one sits on the the PV value chain. The barrier is fairly high for those seeking to become a Trichlorosilane or polysilicon producer. Such a move requires special permitting, large capital investment, and several years of planning and construction. The barrier is much lower at the other end of the PV value chain (downstream) as it does not require a large amount of capital and the business can become operational very quickly. As a result, companies involved in the Trichlorosilane and polysilicon production tend to achieve the highest profit, followed by solar cell manufacturers.

At SunSi, we believe that the best place to be involved on the PV value chain is exactly where we are - as a Trichlorosilane producer.

Making Trichlorosilane (TCS)

The process of producing Trichlorosilane begins by mining for relatively pure silicon dioxide (sand or quartz). The next step in the process is to separate the silicon from the oxygen which is achieved by heating sand grains containing silicon dioxide with carbon at very high temperature. At the end of this stage, the silicon or metallurgical grade silicon (MGS) is about 97% pure.

In order to reach a purity level suitable for semiconductor device and solar applications, the MGS goes through a purification process, which involves the reaction of MGS with hydrogen chloride. This reaction will finally form Trichlorosilane.

The distillation process, which is the final step in producing high quality Trichlorosilane, is all about bringing impurities below the part-per-billion (ppb) level. Liquefied Trichlorosilane at room temperature is purified by the distillation process until the impurity levels are acceptable.

SunSi Energies... the only "pure play" public company in the world
focused on TCS production!