Comments on the Development Electronic Gases

By Sun Funan, Zhonghao Guangming Research&Design Institute of Chemical Industry Co., Ltd.

Driven by the brisk demand for electronic gases in the solar energy market a few years ago, the industrialization of electronic gases in China has been greatly accelerated. At present, China still lags apparently behind the foreign countries in the technical level of gas production, and the vast majority of products can only meet the demand from low-end users. However, among all kinds of major high-purity electronic gases as well as mixed gases needed for the manufacture of integrated circuits (IC), several varieties are successfully developed each year in China. Based on the development speed in the past few years, in the near future, China’s electronic gas sector will fully catch up with that of the developed countries both in the quantity of varieties and product quality, and China will have world-class manufacturing companies at that time. The introduction to a few important electronic gases for semiconductor production is as follows:

High purity silane (SiH4)

Silane is an electronic gas variety with the most extensive application and the greatest influence. Due to being flammable and explosive, as well as high purity requirements and high technical difficulty, the production technical level of silane gas represents the highest level of specialty gas production technology to some extent. Many foreign gas companies have silane plants in Japan and Korea, but have no silane plants in China. Zhejiang Zhongning Silicon Co., Ltd. has played a great role in the industrialization development of silane in China, and can produce 4 500 tons of high purity silane each year. According to a favorable news, Xiao Wende, professor of Shanghai Jiao Tong University, recently used multifunctional reaction technology to overcome the existing defect of low transformation efficiency of trichlorosilane in UCC process and increase the transformation efficiency to over 99%, and Shanghai Jiao Tong University cooperated with Henan Pingmei Shenma Group to construct 1 200 t/a silane industrialization demonstration project that was recently succeeded in trial operation. In China, trichlorosilane which is the raw material for silane production through UCC process is easy to be obtained, giving good prospects for the popularization of UCC process. The consumption of high-end silane in China will sure depend less on imports in the future.
In 2014, the price of silane drops significantly both in domestic and global markets. It is reported that the domestic market share of silane from Taiwan increases drastically, and its price is close to the level of silane originated from Korea. Once reaching the highest level of RMB3/g, the price of Korea’s silane is less than RMB0.3/g. It is reported that Inner Mongolia Shenzhou Silicon Industry Co., Ltd. is still conducting the experiment of using UCC process to produce silane. It is suggested that domestic silane players should cooperate with each other, play their own advantages like Zhejiang Zhongning Silicon Co., Ltd.’s silane purifying technology and management experiences, join hands to form silane industrial alliance, and absorb the abundant private capital to construct production units in various regions of China, in order to avoid vicious competition and improve the perception of the “Made in China” brand for silane products.

High purity nitrous oxide (N2O)

The manufacture of semiconductor, LED, TFT-LCD and photovoltaic devices needs high purity N2O. At present, China’s supply of N2O is in serious shortage, and N2O in China is mostly imported from Korea.
In China, a large amount of byproduct tail gas containing N2O is produced in the production of adipic acid, and the content of N2O reaches 38.4%. N2O is one of the gases with the most serious damage to the aerosphere and its greenhouse effect is 310 times that of carbon dioxide, so plants all make great effort to decompose N2O. China has many adipic acid producers and producing one mol of adipic acid can generate 0.8-1.0 mol of N2O. Therefore, the amount of N2O waste gas generated each year is huge, and if it is recovered and utilized, the profound economic and social benefits will be undoubtedly achieved. It is suggested that instead of spend high price to buy foreign N2O production units, domestic players should pay more efforts on the development of comprehensive utilization of adipic acid tail gas. It is reported that a company in Beijing can produce the equipment that is similar to that for the synthesis of N2O using dry process in foreign countries, and has constructed production lines in Shanxi province and Beijing to produce a large amount of N2O. At present, the company is also dedicated to the production of high purity N2O.

High purity chlorine-containing gases (Cl2 and HCl)

The sectors like TFT-LCD, optical fiber, LED and IC all need chlorine with a very high purity. The production of high purity chlorine is simpler than that of high purity hydrogen chloride. However, chlorine is included in the highly toxic chemicals, and local governments are very strict in the management of chlorine, having a very negative effect on the enterprises’ qualification approval for high purity chlorine production. At present, Beijing Huayu Tongfang Chemical Technology Development Co., Ltd. has put its high purity chlorine into the market, and many enterprises have also planned to produce high purity chlorine. Zhejiang Juhua Co., Ltd. has also produced a large amount of bottled anhydrous hydrogen chloride, and put them into the market. The entering of enterprises like Zhejiang Juhua Co., Ltd. with good chemical basis and apparent resource advantages into domestic specialty gas sector will have a profound impact on development and changes of China’s gas industry.

High purity arsine (AsH3)

The production of semiconductor compound gallium arsenide needs to use a large amount of high purity arsine. During the 8th Five-Year Plan period (1991-1995) or even earlier period, China conducted the research on the series products of high purity arsine, and relied on the domestic technology to produce large quantities of high purity arsine. The domestic production technology of high purity arsine was mainly from Baoding Red Star Chemical Plant. However, due to the reform of the enterprise, the domestic production of high purity arsine suspended. At present, China has no domestic high purity arsine products. Arsine gas is considered as one of the most toxic gases. The manufacturing process of high purity arsine involves the compounds with various forms that are related to "arsenic", so the production approval and technology of arsine are very difficult. It is reported that the production of high purity arsine in the United States is completed in the desert areas.
Due to the special chemical properties of arsine, it is very difficult for China to import arsine from abroad, even if the import price is very high. The supply shortage of arsine has had an impact on China’s economic development and national security. Many domestic enterprises produce a large amount of products that are related to arsenic, so it is believed that the domestic production of arsine will not be long delayed. The technologies for the synthesis, purification, detection and security of arsine are very similar to the production of phosphine that has been conducted by Zhonghao Guangming Research & Design Institute of Chemical Industry Co., Ltd., and their reaction conditions are almost the same. Phosphine can be successfully produced, and it is expected that the domestic production of arsine will be soon achieved. Domestic players should consider playing their own advantages and jointly carrying out the research and industrialization of high purity arsine.

High purity germane(GeH4)

High purity germane is an important gas for the manufacture of film solar cells, and China’s high purity germane has been dependent on imports for a long time. Voltaix (being acquired by Air Liquide of France) of the United States and Linde Electronics of Linde AG are the leading high purity germane producers. A company from Fujian province has produced a large amount of high purity germane as well as mixed gas containing germane for the use of film solar cells, and its product quality can fully meet the requirements. The successful localization of germane has offered a valuable experience to the localization of Si2H6 with similar property and use. At present, the Si2H6 price in Chinese market is as high as RMB50 000/kg.

High purity xenon (Xe)

Xe is an important gas used in the sectors such as electric light source, semiconductor and spaceflight. In 2013, Xe in China was in short of supply, and its price once climbed drastically to the highest level, RMB150 000/Nm3. The unexpected growth of demand and the profitability strongly stimulated the development of China’s Xe production technology. In 2004, the gas producers with Baosteel Gas Co., Ltd. as a representative use Xe extraction equipment (enterprises in Shanghai and Hangzhou of Zhejiang province can build Xe extraction units) designed and manufactured by domestic enterprises, and according to the characteristics of China’s gas raw materials (serious air pollution and high content of fluorocarbon compounds), absorb the advantages of foreign technology to design high purity rare gas purification unit with a capacity of 600 Nm3/a Xe and 6 000 Nm3/a Kr. Being successfully put into operation in May 2014, at present, the unit can produce 300 Nm3 Xe and 6 000 Nm3 Kr each year, and the quality of the products can meet the requirements of China’s national standard.
The air separation enterprises that are matched with the traditional iron and steel industry are influenced by the iron and steel industry, the production of rare gas lacks stamina. With the development of China’s coal chemical sector, the traditional pattern of Xe purification only relying on the matching gas with iron and steel industry will have a fundamental change. It is estimated that many companies that can extract Xe from liquid oxygen containing rich Xe will appear in China. The successful production of high purity Xe in Baosteel Gas Co., Ltd. indicates that China has realized the leap in Xe extraction technology and equipment manufacturing. The equipment of JSC of Russia will surely face challenges from domestic air separation plants, and the high cost of equipment may become history.

Prospects

1. China’s specialty gas sector, especially the electronic gas sectore, has completed the enrichment of the product varieties. In the future, China’s specialty gas sector will make progress in product quality, and the quality gap of gas between China and foreign developed companies will be gradually narrowed. With the development of the industry, the domestic large enterprises with financial strength or capital will be in favor of gas industry.
2. Due to the ever-fiercer competition among the specialty gas industry, a large number of integrations among enterprise will emerge in the future, many domestic large gas companies with rich varieties and abundant capital strength will appear, and many small and medium enterprises will be phased out or merged by large enterprises. At present this transformation has happened quietly.
3. China’s gas enterprises will quicken their steps of “going out”, and will set up gas companies in other Asian countries.
4. The cycle for maintaining stable prices of standard gases and electronic gases will be greatly shortened, the ratio of regional production of standard gases will greatly increase, and the standard gas plants will also appear even in the relatively backward regions.
5. The technical personnel of specialty gas industry are more deficient than that in the past. Although China’s specialty gas industry will develop rapidly, the lack of new generation of technical personnel and many adverse characteristics of dangerous chemical products will lead to the shortage of talented people in the industry.