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Supply chain impact of China's gallium export controls
Zhan Yiren
2023-07-11
The Chinese government announced without warning that it would impose export controls on gallium and germanium metals.
A few days ago, the Chinese government announced without warning that gallium and germanium metals will be subject to export controls. Immediately, the media reported extensively, especially focusing on this as a counterattack by the Chinese government to the United States, Japan and Europe, which imposed many restrictions on China on semiconductors.
Both gallium and germanium are important materials in the semiconductor field, especially gallium, whose production in China accounts for more than 80% of the world, plays a key role. The entire supply chain is beginning to smell tension, fearing that supplies will be affected.
Among compound semiconductors, gallium arsenide (GaAs), gallium phosphide (GaP) and gallium nitride (GaN) all require the use of gallium metal, and related products include 5G mobile phone RF power amplifiers, wide bandgap power components, LEDs and Electronic and optoelectronic components such as semiconductor lasers have a huge impact.
The impact of gallium on the supply chain can be divided into two categories, one is the substrate, and the other is the epitaxial layer. The thickness of the substrate is usually 500 microns, while the thickness of the epitaxial layer is tens of microns, or even less than 10 microns.
Gallium phosphide substrates are less used, while gallium nitride has no substrates, so gallium arsenide is the bulk of substrate supply. Sumitomo of Japan, AXT of the United States, and Freiberger of Germany are the main suppliers; the three players have dominated the global gallium arsenide substrate market for more than 30 years, and it is a stable and mature market with an annual output value of about 300 million US dollars .
In the past 10 years, China's red supply chain has begun to enter the gallium arsenide substrate market. Taiwan's foundry and LED factories have used it, and the quality and price are competitive. If China begins to control the export of gallium, the above three companies will be affected in the short term, but the overall supply chain will not be affected much. It is not difficult for Chinese suppliers to expand the production capacity of GaAs substrates.
With gallium metal in the epitaxial supply chain, the influence that China can exert is even weaker. Because almost all related epitaxial layers are completed by metal organic chemical vapor deposition (MOCVD), and the main chemical involved in the reaction is trimethylgallium (Trimethylgallium; TMG), TMG suppliers are from Europe, America and Japan .
If China controls the export of gallium, the first to bear the brunt will be China's thousands of MOCVD units, as well as the entire compound semiconductor industry.
After talking about gallium, let's take a look at the supply chain of gallium nitride.
According to Yole's recent report, China's Innoscience's GaN component output value will surpass PI, EPC, Navitas and other U.S.-based component design companies for the first time in the first quarter of 2023, and Innoscience is its own 8 Its products cover high-voltage and medium-low voltage components, and it competes with the above-mentioned American companies that use 6-inch wafer foundry in the form of IDM. It is self-evident. In the past, wafer foundries introduced gallium nitride components in order to bring new business opportunities to the old 6-inch factories. However, more than ten years have passed, and the yield rate and cost of 6-inch factories have not been effectively improved. As a result, the biggest bottleneck of GaN today is that the price is too high and the market development is limited.
Innosec's business model, although there is a considerable capital investment in the early stage, but the future operation will gradually improve, we will wait and see.
Gallium nitride is an extraordinary semiconductor material not only because of its wide energy gap characteristics, but also because of a characteristic that other types of semiconductors do not have. In general semiconductors, every time an electron is produced, it will be accompanied by a positively charged ion. When we want more electrons or current in the component, there will be more positive ions, and the electrons will encounter more scattering ( scattering), the electron mobility is reduced, and finally leads to a limited increase in current. The electrons in the gallium nitride device are caused by the polarization of the crystal and the stress between the epitaxial layers, so there are no positive ions, so even if there is a high electron concentration, the electrons can still maintain a considerable mobility . This significantly improves the on-resistance and switching speed of the components, two of the most important characteristics of a power conversion system.
In my previous article, I used these two characteristics to compare with silicon substrate components. In 650V components, GaN has a 10 times advantage over silicon components; for 100V components, this advantage is reduced to 3 times; for 30V components, the advantage is still 30%. Therefore, gallium nitride components should be widely used in power conversion systems. However, the biggest obstacle today is cost. If the cost of gallium nitride can be reduced by half, it will be very competitive. This depends on using 8-inch wafer fabs in the supply chain and increasing the epitaxy capacity of each MOCVD.
The Chinese government's decision on the export control of gallium has been carefully considered. On the one hand, it can respond majesticly to the sanctions imposed by Western countries and Japan, but on the other hand, it will not cause too much negative impact on the industrial chain. After all, China has a complete strategic layout for the compound semiconductor industry.
https://www.digitimes.com.tw/col/article.asp?id=12180
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