Do you wish to understand the relationship between an RF semiconductor and the frequency range of its operation? Do you want to learn more about RF semiconductor materials like gallium nitride and silicon carbide? Are you interested in RF semiconductor applications? Keep reading to find out what RF semiconductor materials are, how their electrical properties vary,RF semiconductor devices are used to build equipment that is used for the amplification, and their many applications from modern consumer electronics that you use every day to the sophisticated instruments used by the aerospace industry.
What Are RF Semiconductor Devices?
filtration, phase shifting, and switching of radio frequency signals. They are used in everything from consumer devices such as smartphones to telecommunication and defense applications. Semiconductor materials such as gallium-arsenide, gallium-nitride, indium-phosphide, and other silicon-based materials are the most widely used.
The differing physics and the resulting electrical properties of these semiconductor materials determine their use case. Depending on which material is used, RF semiconductor devices will exhibit various frequency characteristics, allowing manufacturers to create a wide range of devices like oscillators, switches, power amplifiers, antenna tuners, attenuators, couplers, filters, phase shifters, and duplexers to name a few.
The frequency band for RF semiconductors could go from VHF (Very High Frequency) used in radio and television broadcasting to the SHF (Super High Frequency) used in home Wi-Fi routers and microwave antennas. Going even further, there is the EHF (Extremely High Frequency) range which lies between SHF and the far infrared band which supports scientific research applications, military radar systems, and even the airport security scanners passengers walk through. The increasing penetration of 5G networks is due to advancements made with RF semiconductors that utilize the lower part of the EHF frequency band.
Apart from their operational frequency ranges, each RF semiconductor material will also have its own operating temperature and electron mobility. They also have their own unique band gap energy, which is the minimum energy needed to move electrons from the valence band to the conduction band, allowing the semiconductor to conduct an electric current. These factors determine the performance, bandwidth, noise, light-emitting qualities, ability to operate reliably under extreme heat, and cost of an RF semiconductor device.
What Are RF Semiconductor Applications?
RF semiconductor devices are used today in many applications that range from consumer devices to the telecommunication industry, as well as industrial and military equipment. Let’s look at the product portfolio for RF semiconductor-based devices.
Consumer Devices
In this section of the RF semiconductor market, the main driver of growth for the past decade has always been smartphones and other wearable devices that are growing in popularity. This type of electronic device has multiple amplification and switching functions, each with its own frequency band. The RF transceiver as well as Bluetooth, Wi-Fi, and GPS elements within smartphones are all made from RF semiconductor parts.
Telecommunication Industry
As smartphone users are accessing social media applications and streaming video content on services like Netflix, their data consumption rates have been skyrocketing in recent years. As a result, the mobile networks that support them have to handle increasingly faster data transmission rates. Wireless network operators have to develop more sophisticated modulation techniques and find solutions to issues like increased network traffic. Their infrastructure has to support a wide range of frequencies and power levels at their base stations with devices such as repeaters and power amplifiers.
Therefore the rise in demand for smartphones and social media apps worldwide has also resulted in developments in mobile communications technology such as 4G and 5G. The RF semiconductor materials used in wireless infrastructure such as antennas will require different properties than the ones used in smartphones.
Automotive Industry
RF semiconductor-based devices are now making their way into the automotive market. The low-noise amplifiers used in smart vehicles are the crucial components that make their radar systems work along with infrared cameras and other sensors. It is through this that advanced assistive driving features like collision warning, blind-spot detection, and lane-departure warning systems are possible. RF semiconductor technology is essential for vehicle-to-vehicle and vehicle-to-infrastructure communications to work in the future to support self-driving cars and even the smart cities of tomorrow.
Industrial Applications
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Industrial automation in manufacturing applications is another area where RF semiconductor-based technologies are making a difference. Today’s production lines include sophisticated robotics and manufacturing equipment that need to be monitored and controlled remotely. The centralized systems that operate them need to communicate and collect data from their sensors as well as maintain a constant connection with them. This is also enabled through the use of RF semiconductor technology.
The semiconductor industry itself is expected to start using Industry 4.0 manufacturing methods to automate processes. This is possible through the use of sensors that collect real-time data during production, and advanced analytics that provide engineers with ways to monitor performance. Predictive maintenance of automated equipment is also possible.
Aerospace And Defense Applications
The aerospace and defense industries make up the other applications of RF semiconductor technologies. These include advanced radar, navigation, countermeasures, and communication systems. In fact, many of the great strides made in the early days of semiconductor technology were due to research and development conducted by the US military.
For example, parameters such as switching response time, noise figure, signal linearity, frequency stability, and RF output power were absolutely critical for a specific device to function as intended. The success of operations and human lives depended on the reliability of such a device. Therefore, devices needed to be designed for hard use but still deliver great performance consistently. RF semiconductor technology used in satellites and high altitudes has to work in extreme conditions like massive temperature variations and electromagnetic interference.
The performance, reliability, and ease of manufacturing of RF semiconductor technology we enjoy today were mostly thanks to groundbreaking studies done for aerospace and military applications long before these devices made their way into consumer electronics. These sectors still drive massive growth in the global RF semiconductor market today.
RF Semiconductor Materials And Their Frequency Ranges
The earliest solid-state transistors made from germanium were developed in the late 1940s by the Bell Labs team led by William Shockley. While early computers made use of a germanium transistor, it wasn’t the most suitable due to temperature and reverse leakage issues. These problems were then resolved with the development of silicon-based transistors.
While silicon quickly became the semiconductor material of choice for integrated circuits made at a high volume, research conducted by the US Department of Defense in the 1980s started looking for an alternative material. These research programs proved successful, with gallium arsenide being selected as a great RF semiconductor material suitable for high-frequency amplifiers.
Since then, many types of RF semiconductor materials have been created, each with its own operating temperature, frequency ranges, bandgap, switching speed, and other electrical properties.
Silicon (Si)
Silicon is found in abundance and is easy to process through silicate minerals, making it one of the cheapest semiconductor materials to manufacture. Combined with its widely understood fabrication techniques, makes Silicon one of the most popular semiconductors in existence today.
Silicon-based semiconductors are easy to manufacture and deliver great performance. CMOS technology where both digital and analog circuits are integrated on a single chip is possible because of this. While silicon is one of the cheapest and easiest to fabricate, other RF semiconductor materials have advantages in terms of performance and reliability in more demanding applications.
Gallium-Arsenide (GaAs)
Gallium-arsenide is an RF semiconductor material with higher electron mobility than silicon. This gives them high gain and fast switching speeds, making them very useful to build amplifiers. The material can support functionality at frequencies over 250 GHz and creates less noise.
Gallium-arsenide also has high thermal stability, making it useful in a wide operating temperature range without the risk of overheating.
Gallium-arsenide also has a direct bandgap, allowing it to absorb and emit light in a way that silicon which has an indirect bandgap cannot. This allows it to be useful to create infrared light-emitting diodes (LEDs), and laser diodes. Furthermore, the unique band gap makes gallium-arsenide resistant to radiation damage, making it useful in space applications. The bandgap is also wide, making it highly resistive, a useful property for integrated circuit substrate materials.
While economies of scale have made silicon the most widely used material, gallium arsenide is used extensively in everything from mobile phones to satellite communications, high-frequency radar, and point-to-point microwave links.
Gallium-Nitride (GaN)
Gallium-nitride has a wide bandgap as well and can absorb and emit visible light near the ultraviolet region. It has been in use to make blue LEDs since the 1990s and full-color LED displays were only possible through them. The violet laser diodes used to read the information contained in Blu-ray discs are made from GaN-based materials.
Gallium-nitride also has high electron mobility, high thermal conductivity, high breakdown voltage, high power density, and high switching frequency. This makes it good at transferring a current without losing too much energy as heat. This makes them useful for the production of MOSFET and MESFET transistors which allow the automotive industry to make electric cars.
The high power density of power ICs (integrated circuits) made from gallium-nitride makes it possible to produce lighter and smaller devices such as laptop and mobile phone chargers. GaN-based materials are also used to develop sophisticated military radar systems used by both fighter jets and unmanned aerial drones. These equipment made from GaN semiconductor materials are well-known and trusted for their high performance and reliability during missions.
Silicon-Carbide (SiC)
Silicon carbide is also known for high electron mobility and its large bandgap energy. The first commercial light-emitting diodes were made from SiC long before gallium-nitride took over its position. Its electrical properties made silicon-carbide useful in producing fast, high-temperature, and high-voltage devices used in power electronics. Schottky diodes, junction-gate FETs, and MOSFETs which benefited from SiC’s high switching frequency were the earlier mass-produced devices.
Crystal defects made early devices have poor reverse blocking performance, although researchers have been working on improvements for a long time. Packaging is another issue faced by silicon-carbide RF semiconductors with more efficient methods to get the heat out of the devices required. However, SiC has a higher power density and can handle a higher operating temperature than pure silicon semiconductor devices.
The Tesla Model 3 used SiC MOSFET chips which allowed them to reduce weight and size much more than what silicon would’ve offered. Following this, other manufacturers in the automotive industry are also following Tesla to develop power electronic devices made from silicon-carbide chips.
Indium-Phosphide (InP)
This RF semiconductor material has vastly superior electron velocity compared to silicon and even gallium-arsenide. This has allowed researchers to create ultra-fast transistors that operate at over 600 GHz. 5G wireless communications with their fast data rates which require frequencies above 100 GHz may need this type of semiconductor materials although these options are still being explored.
Indium-phosphide also has a direct bandgap which makes it useful in optoelectronic applications. This allows for the development of laser technology suitable for fiber optic cables used in data centers and to connect mobile wireless base stations. The type of wavelengths possible from lasers made using InP-based materials makes them suitable for LiDAR which is used for object identification and classification. This is a core technology that will be deployed by the automotive industry for self-driving vehicles soon.
Furthermore, indium-phosphide is also used for RF semiconductors found in security scanning systems as well as biomedical applications such as cancer-tissue identification.
RF Semiconductor Market Trajectory
Apart from the above-mentioned RF semiconductor materials, others like silicon-germanium (SiGe), aluminum-nitride (AlN), and boron-nitride (BN) have useful applications as well. New materials are constantly being developed to improve their electrical and light-emitting properties as well as their ability to work under tough conditions and varying temperatures. The operating frequency is of course a huge factor as well, determining what applications each RF semiconductor device can be used in.
The two things that are expected to cause a massive shift in the future trajectory of the RF semiconductor industry are the Internet of Things (IoT) and 5G technology. Apart from the billions of devices that will be connected together, higher data rates will need to be supported to make them work. The battery life, data capacity, data transmission rate, size, and weight of both consumer and industrial electronics will all be dependent on the next generation of RF semiconductor devices that will be powering them.
FAQs
RF semiconductor devices are specifically designed integrated circuits that are used in radio frequency (RF) applications such as wireless mobile networks, satellite transmissions, and microwave communications.
RF semiconductor materials are semiconducting materials that have desirable electrical and optical properties when used in radio frequency (RF) applications. High electron mobility, wide temperature operating range, low noise, wide bandgap, high switching frequency, and high power density are some of these properties.
RF semiconductor materials such as silicon, silicon-germanium, gallium-arsenide, gallium-nitride, and silicon-carbide are the most commonly used in practical applications.
