With the rapid development of 5G and electric vehicle markets, will SOI wafers be out of stock?

5G wireless communications require higher frequencies to achieve faster network speeds. Compared with traditional gallium arsenide (GaAs) and silicon-on-sapphire (SOS) technologies, RF-SOI can provide excellent RF performance and lower costs at the same time.

Based on the above advantages, as one of the key components in the front-end module of mobile smart terminals, the RF switch chip has abandoned the original GaAs and SOS process and switched to the lower-cost RF-SOI process since 2013.

At present, a complete SOI industry chain has been formed in China from materials, chip foundry, RF devices to system design and complete machines.

Recently, the "2019 International RF-SOI Seminar" jointly organized by the SOI Industry Alliance, Shanghai Simao Technology, VeriSilicon Microelectronics, Silicon Industry Group and SIMIT was held as scheduled at the Shanghai Pudong Shangri-La Hotel. The guests discussed the various development opportunities of RF-SOI. Now that 5G demand is so broad, will SOI wafers be out of stock?

EDN reporters took this question to interview Dr. Carlos Mazure, Chairman and Executive Director of the International SOI Industry Alliance, Dr. Jon Cheek, Executive Director of the Alliance, and Dr. Wang Qingyu, General Manager of Shanghai Simao Technology Co., Ltd. in a later media interview.

Dr. Carlos Mazure, Chairman and Executive Director of the International SOI Industry Alliance, pointed out that the global consumption of 12-inch wafers is currently 6.5 million pieces per month, and the consumption of 8-inch wafers is about 8.5 million pieces per month.

The difference between 8-inch and 12-inch wafers is that 8-inch wafers are mainly used for single devices, while 12-inch wafers have smaller line widths and can be better integrated. Dr. Jon Cheek, executive director of the International SOI Industry Alliance, believes that in the future, when millimeter waves are applied, there will be a huge demand for 12-inch SOI wafers.

However, Dr. Cheek believes that the current global 12-inch production capacity is sufficient, because there are also limited RF-SOI foundries, including the big ones GlobalFoundries, towerjazz, Sony, TSMC and UMC, so there is basically no need to worry about insufficient SOI wafer production capacity.

In addition, Dr. Wang Qingyu, General Manager of Shanghai Simgui Technology Co., Ltd., also pointed out that Simgui's current production capacity is expanding, and by the end of this year, the capacity will reach 30,000 pieces per month and 360,000 pieces per year.

"In addition to 8-inch, Simao is also planning 12-inch RF-SOI. Our factory has been built." Dr. Wang pointed out that 12-inch is developing rapidly overseas, but most of the total volume is still on the 8-inch line.

In the future, the RF industry chain will be transferred to China. Dr. Wang pointed out that the domestic mobile phone industry is now very strong, with more and more design companies, but the distribution is very uneven and the foundry capacity is not enough. China's mobile phone production accounts for about 1/3 of the world's total, and the future opportunity must be how to strengthen the domestic industry.

He said that the RF front-end supply chain is currently mainly supplied by four foreign companies, Murata, Skyworks, Qorvo, and Broadcom. "The starting point in China is relatively low, but the growth rate is very fast, with a lot of design companies. Why do design companies develop faster? Because once they have design capabilities, they can use foundries around the world. Domestic foundries are developing relatively slowly.

Dr. Wang once worked at SMIC. From a technical perspective, he pointed out that the RF back-end needs copper. Copper has a high electrical conductivity, while aluminum has a lower conductivity. However, the only foundry in China that has copper technology is SMIC Fab 3. Other foundries do not have copper technology, so the performance is relatively low.

 "However, with the redistribution of the industrial chain, the domestic industrial chain will rise quickly." He added that 90% of our wafers are now exported, and as the domestic ecosystem improves, this proportion will definitely change in the future.