Traditional silicon semiconductors need to find the next generation of semiconductor materials due to their own development limitations and Moore's Law. The high electron mobility, direct energy gap, and wide energy band characteristics of compound semiconductor materials are just in line with the needs of future semiconductor development. The trend will be led by applications such as 5G communications, automotive electronics and optical communications.
Compound semiconductor market analysis
According to the current compound semiconductor component supply chain, the wafer manufacturer selects a substrate with appropriate characteristics for the initial step of the component manufacturing process. Materials such as silicon, germanium and gallium arsenide are used as the substrate for the semiconductor component manufacturing process. After the substrate is determined, epitaxy According to the functional requirements of different components, the factory grows several layers of compound semiconductor epitaxial layers on the substrate. After the epitaxial layer is grown, the entire component manufacturing process is completed through the steps of IDM factory or IC design, manufacturing and packaging. Finally, terminal product manufacturers assemble and configure component circuits to produce smart application products such as mobile phones and automobiles.
Compound semiconductor applications in the end market
Component products are developed based on the characteristics of compound semiconductor materials (such as high temperature resistance, high voltage resistance, radiation resistance and luminescence), and the end market is divided into 5 areas: power control (Power Control), wireless communication (Wireless), infrared (Infrared) ), Solar and Photonics.
Take power supply control as an example. As materials such as gallium nitride (GaN) and silicon carbide (SiC) have good resistance to high voltage and high frequency, they are suitable for the manufacture of Power Factor Correction (PFC) and high voltage power High-power components such as amplifiers (High Voltage Power Amplifier, HVPA) are important indicators supporting the field of compound semiconductor power control at this stage.
In terms of solar energy and optical communications, as gallium arsenide (GaAs) materials have a better energy conversion rate and are suitable for receiving signals from red and infrared wavelengths, they are suitable for the development of solar cells (Photovoltaics) and photodetectors (Photonic Detection). ) And other application fields.
In recent years, the field of mobile phone communication has been booming, which has driven the growth of the demand for components such as filters, switching components and power amplifiers (Power Amplifier), which are key components of wireless modules. GaAs materials have low noise, low power consumption, The characteristics of high frequency and high efficiency have been widely used in mobile phone communication and occupy an important position, driving the demand for GaAs epitaxy to increase year by year.
In the national defense field, the current demand for infrared light (such as infrared photothermal imaging and high-function night vision goggles) is dominated by military fields such as medium and long wavelength infrared light (LWIR, MWIR), which also drives the demand for gallium arsenide epitaxy. . In the biological and medical fields, indium phosphide (InP) materials are used as the key core of the laser light source, making the demand for related epitaxy rising. On the whole, applying the diverse material properties of compound semiconductors to the field of related components can create many new possibilities and drive the continuous development of the epitaxial industry.
Current status of compound semiconductor epitaxy plants
The current commercial epitaxy process technology for compound semiconductors can be roughly divided into MOCVD (metal organic vapor deposition) and MBE (molecular beam epitaxy). In terms of growth technology, MOCVD growth conditions are carried out by gas phase methods, and hydrogen (H2 ) Or nitrogen (N2) or other specific carrier gas (Carrier Gas) to make the Group III (III A) and Group V (VA) gases uniformly mixed, and then introduced into the reaction chamber, and then pass through the appropriate reaction temperature (400 ～800 degrees), let the gas crack and grow on the substrate. MBE growth conditions are through element heating, and the required epitaxial element is heated and sublimated to form a molecular beam through a cavity in an ultra-high vacuum environment. When the molecular beam contacts the substrate, the desired epitaxial structure can be formed.
If the advantages and disadvantages of MOCVD and MBE epitaxy equipment are analyzed at the mass production rate, MOCVD is introduced into the reaction chamber in a gas phase, and its speed is 1.5 times faster than MBE (MBE needs time to heat to form molecular beams); but in terms of epitaxial quality, Since MBE can precisely control the growth of molecular beam epitaxy, it has better results than MOCVD.
Observing the current development trend of epitaxial plants, although MBE requires a higher cost and slower speed, it meets the needs of high-precision component products in the fields of national defense and optical communications. At present, most IDM factories of compound semiconductors choose MBE epitaxy equipment as their growth method. In addition to IDM factories, the British IQE and IET foundries also use MBE as their in-plant epitaxial equipment.
On the other hand, because MOCVD adopts the vapor phase growth method, it can quickly and extensively grow epitaxially. Although its epitaxial quality is slightly inferior to that of MBE, it is attractive for devices that require a large amount of large-area epitaxial growth, such as solar cells. Components etc. Currently, 60% of global compound semiconductor epitaxy plants choose MOCVD machines that can grow on a large scale; another 40% choose high-precision MBE equipment.
According to the estimated revenue share of global compound epitaxy plants in 2018, the global compound semiconductor epitaxy industry revenue has exceeded US$490 million, and British IQE revenue accounted for about 44% of the overall revenue, which remained the same as 2016 revenue The proportion is firmly ranked as the leading epitaxy; the second-ranked United Asia, the estimated proportion in 2018 will remain at 16% (same as 2016). In addition, the revenue of new optoelectronics dropped from 17% in 2017 to 14% of the estimated 2018; the revenue of IET, the second largest MBE epitaxy plant in the world, dropped from 7% in 2017 to 2018 The reason for the decline of the estimated 5% of the year is related to the Sino-US trade war and the lower than expected global mobile phone sales, resulting in a slight decline in market share.
The future development of compound semiconductor epitaxy
In view of the future terminal market demand of compound semiconductors, according to the characteristics of different components, it can be divided into three areas: 5G chips for transmission and wireless communication, high temperature and high voltage resistant automotive chips, and optical communication chips that can receive and return signals. The development of components for 5G chips, automotive chips and optical communication chips will drive the revenue and capital expenditures of epitaxial plants in the future and establish future investment directions.
The future trend of the terminal market
From the development trend of compound semiconductors, it can be seen that the future component demand will be high-speed, high-frequency and high-power, connecting applications in the fields of 5G communications, automotive electronics and optical communications, and breaking through the limitations of silicon semiconductor Moore's Law.
The future trend of epitaxy factory terminal products; Source: Tuoqi Industry Research Institute
Silicon semiconductor devices are limited by electron mobility, luminous efficiency, and ambient temperature, which make it difficult to meet device characteristics. Therefore, when compound semiconductors appear, they have characteristics such as high electron mobility, direct energy gap, and wide energy band. , Provide new opportunities for the future of component development. With the development of science and technology, the device process technology of compound semiconductors has also matured. The traditional silicon semiconductor thin film, exposure, development and etching process steps have been successfully transferred to compound semiconductors, which will help the continued development of the subsequent semiconductor industry.
Regarding the future development of the wireless communication field, current manufacturers have gradually upgraded from the original 4G equipment to the 5G infrastructure. The deployment density of 5G base stations will be even higher than that of 4G, and the power components used in the base stations will be replaced by broadband gallium nitride. Power components replace DMOS (Double Diffusion Metal Oxide Half Field Effect Transistor) components. In the base station construction part, currently concentrated in IDM factories (such as Qorvo, Cree and Japan's Sumitomo Electric), and various foundry factories have successively invested, resulting in fierce market competition; in addition, Chinese manufacturers originally intended to acquire foreign manufacturers Entering the GaN foundry market is blocked due to defense and security reasons. Therefore, at this stage, Chinese manufacturers are limited in the development of GaN base stations.
In order to improve the quality of wireless communication, the 5G communication market will strive for lower power consumption and better electronic components. Therefore, compound semiconductor materials such as gallium arsenide and indium phosphide are selected as PA (power amplifier) and LNA ( Low noise amplifier) and other radio frequency components (Radio Frequency, RF).
On the whole, since the gallium arsenide radio frequency component market is mostly controlled by IDM factories (such as Skyworks, Qorvo, and Broadcom), only when the demand exceeds the IDM factory load, orders will be outsourced to other component foundries, and other components will be invested. It is more difficult for manufacturers of component foundries. As the domestic demand for radio frequency components in the Chinese mobile phone market increases and the penetration rate of 5G mobile phones is expected to increase, perhaps China’s foundries can tap into the GaAs foundry supply chain and increase the market share of radio frequency components after the radio frequency process technology of Chinese foundries improves rate.
In the car chip part, due to the use environment requirements (need to operate under high temperature, high frequency and high power), and the inductance and capacitance on the car circuit, the volume of car components is larger than that of ordinary components. Among compound semiconductors, the characteristics of wide-band semiconductor materials such as gallium nitride and silicon carbide will help reduce the size of automotive components.
By replacing silicon semiconductors with gallium nitride and silicon carbide, it has gradually become possible to reduce energy consumption when switching automotive components. When gallium nitride and silicon carbide materials are used as automotive power components, due to the wide band material characteristics, the volume of the surrounding circuit can be greatly reduced, and the weight of the module can be reduced. In addition, gallium nitride and silicon carbide have better heat dissipation characteristics than silicon semiconductors. , It can reduce the cooling system modules, and further move towards the goal of lightweight vehicle.
In addition, automotive chips are also very important for the application of LiDAR sensors. In order to realize autonomous vehicles or unmanned vehicle technology, the LiDAR sensors in advanced driver assistance systems (ADAS) are indispensable. And gallium arsenide epitaxial materials meet the characteristics of its components and are required as light sensors.
In the field of optical communication chips, in order to solve the limitation and bottleneck of the signal transmission of metal wires, the concept of using laser light as the transmission source in the optical fiber was developed, breaking through the original electronic passing through metal cables that are prone to resistance and capacitance time delay (RC Delay) phenomenon, and with the rapid transmission of laser light and the characteristics of not easy to decay the signal, silicon photonics technology (Silicon Photonics) has gradually attracted attention.
Due to the demand of optical communication chips for optical transceiver modules, the demand for PD (photodetector) and LD (laser detector) modules has increased, driving the gallium arsenide and indium phosphide epitaxial markets. In addition, in recent years, mobile phones with 3D sensing applications have a clear growth trend, driving the increase in demand for VCSEL (vertical cavity surface emitting laser) components, and gallium arsenide epitaxy is gradually heating up. In the future, optical communication chips for 3D sensing will have applications in addition to Mobile phones will also be expanded to areas such as eye tracking technology, security, virtual reality (VR) and proximity recognition.
Future Outlook of Epitaxy Factory
Although mobile phone sales in 2018 declined slightly compared to 2017, and mobile phone sales in 2019 will tend to be conservative, the 3D sensing technology of Apple mobile phones has received attention in recent years, which has driven non-Apple camps to accelerate the introduction of the 3D sensing market, prompting VCSELs Increasing demand, the demand for components in the optical communication field has an increasing trend, driving the growth of capital expenditures of some epitaxial plants in 2018.
The possible decline in mobile phone sales in 2019 and the low estimated penetration rate of 5G mobile phones will affect the mobile phone component market (such as PA and LNA) and the revenue performance of epitaxy factories. At this stage, the 5G communication field still needs the base of telecom operators. Taiwan builds and develops the market, and revenue growth in 2019 is limited, which will affect part of the epitaxy factory's revenue.
Due to the harsh operating environment and the need to withstand high voltage and high temperature conditions, automotive chips often choose compound semiconductors such as gallium nitride and silicon carbide; and the electric vehicle market will continue to grow slightly in the future, driving the demand for automotive power semiconductor components, and then Promote the growth of GaN and silicon carbide epitaxy revenue.
In addition, the demand for LiDAR components for advanced driver assistance systems has been increasing year by year, which has led to an increase in the demand for gallium nitride and gallium arsenide epitaxy. Overall, the demand for automotive compound chips will gradually increase in the future, becoming the epitaxy market that continues to grow One of the main kinetic energy.
Source: (Global Semiconductor Watch) WeChat official account, thank you!