The super “power” of 5G – gallium nitride(GaN)
The world is excited about 5G technology. 5G will deliver lightning-fast speeds 20 times faster than 4G LTE and open up a host of innovative applications and opportunities beyond our imaginations.But it also requires overhauling existing network infrastructure—especially RF power applications. GaN technology is the key to driving this new type of infrastructure.
Gallium nitride (GaN) is a relatively new semiconductor for commercial applications. Its power efficiency, power density, and ability to handle a wider frequency range make it ideal for massive MIMO base stations.
Today, we’re going to discuss the value of GaN as a semiconductor, its distribution in the industry chain, key production process challenges, and what we can expect from GaN applications.
1 The value of GaN semiconductors
Gallium Nitride (GaN) is a wide bandgap compound semiconductor material with the following properties.
(1) The high breakdown electric field strength greatly improves the current density and withstand voltage capacity of gallium nitride power devices, while reducing the conduction loss.
(2) The wide band gap and the large forbidden band width greatly reduce the leakage current of the GaN semiconductor device and make it resistant to radiation. At the same time, the wider band gap means that gallium nitride can withstand high voltage, and high voltage means that high-power applications, high output energy density and high temperature resistance can be achieved.
(3) High thermal conductivity and excellent heat dissipation performance, which means that the integration and power density of gallium nitride devices can be higher than those of traditional components.
(4) The electron saturation drift is fast and can work at higher frequencies.
(5) The dielectric constant is small, which can reduce the leakage current of the integrated circuit, reduce the capacitance effect between the wires, and reduce the heating of the integrated circuit.
(6) The chemical properties are stable and not easy to corrode.
(7) Wurtzite-like structure, high hardness.
These properties have propelled gallium nitride into the 5G RF spotlight. GaN can better support the lightweight of electronic products. For example, PC power adapters using GaN transistors are smaller and lighter than chargers that are common today.
According to third-party calculations, after using GaN devices, standard mobile phone chargers can lose weight by up to 40%. Or output more power under the same size condition, similar performance improvements can be achieved in terms of energy efficiency and power density, which are suitable for various electronic products such as consumer, industrial, and automotive.
2 GaN semiconductor industry chain
The links in the GaN semiconductor industry chain are: GaN single crystal substrate → GaN material epitaxy → device design → device manufacturing.
(1) GaN single crystal substrate
GaN substrates are mainly dominated by Japanese companies, and Japan’s Sumitomo Electric has a market share of more than 90%.
(2) GaN epitaxial wafer
GaN epitaxial wafer related companies mainly include Epi-GaN in Belgium, IQE in the United Kingdom, and NTT-AT in Japan. Chinese manufacturers include Suzhou Jingzhan, Suzhou Nenghua and Century Jinguang.
(3) GaN devices
In terms of GaN device designers, there are EPC, MA-COM, Transphom, Navitas in the United States, Dialog in Germany, and Ampleon, which was acquired by Chinese capital, in China.
Among the global independent design and production suppliers (IDMs) of GaN RF devices, Sumitomo Electric and Cree are the leading companies in the industry, with a market share of more than 30%, followed by Qorvo and MACOM. Sumitomo Electric has a large market share in the wireless communication field. It has become Huawei’s core supplier and the largest supplier of Huawei’s GaN radio frequency devices. In addition, there are Exagan in France, NXP in the Netherlands, Infineon in Germany, Mitsubishi Electric in Japan, and II-VI in the United States.
3 Main production processes of GaN devices
One is the gallium nitride GaN RF process based on silicon carbide SiC as the substrate, which is used by Qorvo and most manufacturers. One is the gallium nitride GaN radio frequency process dominated by Macom based on silicon Si as the substrate.
Both RF processes have their own pros and cons.According to Qorvo, the GaN-on-silicon carbide-based GaN RF process has higher power density and better thermal conductivity than GaN-on-silicon-based GaN.
4 Problems to be solved
①The production process of gallium nitride semiconductor materials is relatively complex and the yield is lower than that of traditional silicon semiconductor materials.
②The price of gallium nitride semiconductor materials is high, and the price of MOS tubes using gallium nitride semiconductor materials is nearly 20 times that of traditional silicon semiconductor materials.
③ A large number of gallium nitride semiconductor production process and component patents are in the hands of countries such as Europe, America, Japan and South Korea, and a considerable number of key components also rely on imports.
5 Gallium Nitride Applications
Communication field: 5G high-power base station GaN power amplifier is mainly used in 5G high-power base station, which solves the problem of small area but relatively concentrated data traffic requests in 5G mobile network. The 5G millimeter-wave base station GaN monolithic power amplifier has the characteristics of ultra-large bandwidth and ultra-low latency.
Power semiconductor fields such as electric vehicles, photovoltaics and smart grids: At present, IGBTs used in electric vehicles, photovoltaics, smart grids and other fields are silicon-based materials. In the future, gallium nitride technology will make further breakthroughs and penetrate into the field of IGBT semiconductors. In addition, many mobile phone fast charging solutions also use gallium nitride solutions.
Especially at a voltage of around 600V, gallium nitride has obvious advantages in power management, power generation and power output, which makes the power products of gallium nitride materials thinner and more efficient.
And the GaN charging plug is small in size and high in power, and has the opportunity to unify the mobile phone charger and communication power market in the future.
Military field: It has been widely used in various military radar devices, especially the airborne active phased array radar devices of new fighters.
Electronic field: Gallium nitride transistors are suitable for high frequency, high voltage and high temperature occasions. Based on gallium nitride transistors instead of silicon-based MOSFETs, hard-switching half-bridge DC/DC power modules with synchronous rectification function are produced.
The use of GaN transistors allows DC/DC power modules to operate at higher frequencies without a significant drop in efficiency, at the same time, a small LC filter can be used to achieve low output ripple, which has the advantages of small size, high efficiency, small ripple and fast dynamic response.