Nowadays, the competition of science and technology is increasingly fierce, and the chip technology that attracts the most attention is changing with each passing day. Before news of IBM's 2-nanometre chip spread, TSMC and its partners announced a breakthrough in sub-1-nanometre chips. It is widely believed that humans are approaching the theoretical limits of electronic chips.
Silicon optical chip has the characteristics of high computing speed, low power consumption and low time delay, and it is not necessary to pursue the limit reduction of process size. In the manufacturing process, it is not necessary to be as strict as electronic chip, but must use extreme ULTRAVIOLET lithography machine (EUV).
So, can silicon light chip break through the "ceiling" of Moore's Law, open up a new "track"?
There are still technical bottlenecks that need to be overcome
"The concept of silicon photonics has been proposed for a long time, but it is not easy to make silicon photonics chips." Li Peigang, a professor and doctoral supervisor at Beijing University of Posts and Telecommunications, told Science and Technology Daily that as early as the 1990s, IT practitioners began to look for a successor to the traditional semiconductor chip industry, and photonic computing was once considered the most promising future technology. "Due to technical reasons, until the beginning of the 21st century, enterprises and academic institutions led by Intel and IBM took the lead in developing optical signal transmission technology of silicon chips, hoping to replace the data circuit between chips with optical path." Li Peigang said.
Li Peigang told reporters that silicon optical chip manufacturing technology is based on silicon and silicon substrate materials, the use of complementary metal oxide semiconductor (CMOS) process for optical device development and integration technology, which combines the characteristics of ultra-large scale, ultra-high precision manufacturing of integrated circuit technology and the advantages of ultra-high speed, ultra-low power consumption of photonic technology. It is complementary to the existing semiconductor wafer manufacturing technology.
Li Peigang said that China attaches great importance to the development of silicon optical chip industry. But at first, the domestic high-end silicon chips light is given priority to with design, flow sheet is main or abroad, chip preparation, long cycle, high cost, restrict the development of silicon photonics technology in China, "and limit the development of Chinese chip technology abroad, has adopted a series of measures, the development of silicon light chip companies in China has caused serious influence."
Li Peigang told reporters that the development of silicon optical technology can be divided into three stages: first, silicon-based devices gradually replace discrete components, with silicon to make the optical communication underlying devices, to achieve the standardization of the process; Second, the integration technology evolves from coupling integration to monolithic integration, realizing partial integration, and integrating these devices into different chips through the combination of different devices just like Lego bricks. Third, the integration of optoelectronic technology to achieve full integration of optoelectronic. Integrate both light and electricity to achieve more complex functions. "We are now in the second phase of silicon-optic technology." Li Peigang said.
In his opinion, although silicon-optic technology is maturing and silicon-optic chips are about to enter the stage of large-scale commercial use, there are still technical bottlenecks that need to be overcome, such as non-standard design tools, high requirements of silicon-optic coupling process, and technical challenges such as automatic wafer testing and cutting.
Li Peigang believes that China has made technological breakthroughs in the research and development of silicon optical chips, but in the aspect of industrialization, there are still some problems in the industrialization technology of domestic silicon optical chips, including structural design, manufacturing process, device packaging and application supporting, etc., which need to be developed and mature. "In addition to the technology itself, The industrialization of silicon optical chips will also be affected by comprehensive factors such as materials, technology, equipment, software, talents and market ecology. Therefore, in addition to investing in technological research and development, it is also very important to form a good industrial ecology, build platforms and optimize ecology, and increase cooperation between upstream and downstream of the industrial chain for the development of silicon optical chips." Li Peigang said.
Silicon optical chips are developing rapidly in China
On November 28, 2017, the Ministry of Industry and Information Technology officially approved the construction of the National Information Optoelectronics Innovation Center in Wuhan. The center is jointly participated in by many domestic enterprises and RESEARCH and development institutions such as Optoelectronics Technology, Fiberhome Communication, Hengtong Optoelectronics and so on, gathering more than 60% of the innovation resources in the field of information optoelectronics in China. Bearing the strategic task of solving the "collaborative research and development of key and generic technologies" and "realizing the first commercialization" in China's information optoelectronics manufacturing industry, we strive to solve the situation of "lack of core" in information optoelectronics.
In 2017, The Shanghai Municipal government listed silicon photonics as one of the first municipal major projects, and invested a large amount of funds to layout the r&d and production of silicon based optical interconnection chips, aiming to build the whole industry chain of silicon optical chips, master the key core technologies, and let domestic enterprises get rid of the dependence on foreign suppliers.
In October 2018, United Microelectronics Center Co., LTD., a new national international research and development institution created by chongqing Municipal government, was registered and established in Chongqing with an initial investment of over 10 billion yuan.
The Ministry of Industry and Information Technology released at the end of 2017 "China optoelectronic device Industry Technology Development Roadmap (2018-2022)" pointed out that the current rate of high speed optical chip localization is only about 3%, the requirements of 2022 low-end optoelectronic chip localization rate of more than 60%, high-end optoelectronic chip localization rate breakthrough 20%.
With the policy support, silicon optical chips are developing rapidly in China. In January 2018, China's first silicon photonics technology platform was established in Shanghai, narrowing the gap between China and foreign countries in processing and manufacturing.
On August 29, 2018, Sinotech announced that China's first commercial "100G silicon optical transceiver chip" was officially put into production.
In September 2019, United Microelectronics Center LLC realized the wiring of the 8-inch silicon-based optoelectronics technology process platform. In just a few months, its self-developed silicon optical process has reached a very good level, and officially released "180nm Complete set of silicon optical process PDK" to the world, which marks that the company has the independent process manufacturing capacity in the field of silicon based optoelectronics, and began to provide silicon optical chip flow services to the world.
At the national level, favorable policies supporting silicon optical technology have been coming, and local governments have also entered the board. Shanghai explicitly put forward the development of the photon chip with device, the key breakthrough silicon photonics, optical communication device, photon chip research and development and application of a new generation of photonic devices, such as, the photonic devices modular technology, based on CMOS silicon photonics technology, chip integration technology, photoelectric integration module encapsulation technology research to carry out the key research. Hubei Province, Chongqing Municipality, Suzhou and other governments have taken silicon optical chips as the key industry to develop during the 14th Five-Year Plan period. "It is hard to see substantial differences in layout among different regions based on their plans. "We will develop the silicon optical chip industry by actively introducing new companies and making use of our existing chip industry foundation." Li Peigang said.
Light and electricity will work together for a win-win future
Silicon optical technology has become the next target of the industry because of its many characteristics. With the continuous maturation of industrialization technology and optimization of industrial environment, China's silicon optical chip industry is poised for development.
According to Intel's development plan of silicon photonics industry, silicon optical module industry has
entered a period of rapid development. In 2022, silicon photonics technology will surpass traditional optical modules in terms of peak speed per second, energy consumption and cost. It is predicted that the market of silicon optical modules will grow by 40% and reach $3.9 billion by 2024, accounting for 21% of the overall market size by then.
"At the moment, light and electricity are on two 'racetracks', each with its own application scenario. In logical computing, the future trend is optoelectronic integration, and all-optical computing will take a long time to achieve." Li Peigang said that although the photonic integrated circuit is still in the initial stage of development, but it has become the mainstream development trend of optical devices has become inevitable.
"In general, photonic chips can now replace electronic chips only in individual computing and transmission fields." Li Peigang said that although the two are similar in the process and complexity of manufacturing process, photonic chip structure requirements are not as strict as electronic chips, generally 100 nanometers, "this greatly reduces the dependence on advanced technology, to a certain extent to alleviate the current chip development bottleneck."
"Light has the advantage of light, electricity has the advantage of electricity." 'In some application scenarios, there is competition, but more often, it's a win-win relationship,' Mr. Li said.
"Silicon optical chip technology is not as mature as electronic chip technology, so there are many unknown factors, the future should be a good link between the two." Li Peigang believes that electronic integrated circuit and photonic integrated circuit are complementary. "In the future, we can make full use of the advantages of photonic integrated circuits' high speed transmission and electronic integrated circuits' multi-function and intelligent, and run better on the new 'track'." Li Peigang said.