In recent years, silicon has proven as tough to live with as to live without. The material has trouble hitting the high frequency bands increasingly used in wireless communications, but it is also vital for etching filters, switches, and amplifiers SoCs, which engineers covet for being small and energy efficient.
But on Tuesday, an update came for one of the most successful technologies to bridge that gap. GlobalFoundries, one of the world's largest chip manufacturers, began selling tools to help engineers make chips based on its latest manufacturing process, one that is optimized for millimeter waves, which are considered vital for 5G communications.
The technology is known as a silicon-on-insulator process, more commonly known as SOI. It involves wrapping two layers of silicon around an insulator material - using anything from silicon dioxide to sapphire - slashing power leakage and improving efficiency. It has been used in computer processors and in the development of silicon photonics.
In a configuration called RF SOI, the chips are designed specifically for radio components, ranging from switches to low-noise amplifiers. These are major parts of the front ends that decipher wireless signals flowing in and out of smartphones and communications satellites. For 5G, they will have to support high frequency bands, which are sparsely used in modern cellular equipment or consumer devices.
The new manufacturing process, 45RFSOI, involves etching circuits only 45 nanometers long onto silicon wafers, almost four times longer than the most advanced computer chips under development by GlobalFoundries. But those microscopic circuits are enough to lift RF SOI into high frequency bands, from 24 to 100 gigahertz, where wireless carriers are likely going to move communications after 4G.
The updated process is also the latest example of how companies plan to give RF SOI an edge over the competition. Peregrine Semiconductor, a San Diego-based company that claims to have founded the RF SOI market, revealed the twelfth generation of its technology in January, with the highest linearity and lowest radio losses yet. It worked with GlobalFoundries to render it on 300mm wafers.
But many companies view RF SOI as outdated technology unsuited for the shift toward 5G standards. Smartphone makers are increasingly using tiny mechanisms, grown on silicon wafers and known as RF MEMS, to tune antennas into different frequencies. More competition comes from gallium arsenide, a semiconductor material used in radio components for multiple industries, like test equipment and cellular infrastructure.
"5G is expected to become the dominant worldwide mobile communications standard of the next decade and will usher in a new paradigm in mobility, said Bami Bastani, senior vice president of GlobalFoundries' RF business, in a statement. RF SOI "will help play a critical role in bringing 5G devices and networks to reality."
45RFSOI improves on earlier technology that had been developed for simpler communication systems. The passive devices built on the manufacturing process have high resistivity that maximizes quality factor – a measure of energy efficiency also known as the Q factor – and minimizes the disparity between phase and voltage.
One of the first chipmakers to sign onto the new process is Skyworks Solutions, a maker of wireless chips for smartphones and connected devices. The company has previously used RF SOI in its switching products, claiming that its efficiency and switching speed are better suited to operate over the growing number of spectrum bands used to send messages and stream video.
Peter Gammel, Skyworks’ chief technology officer, said in a statement that the more advanced process will enable the company to further “advance the deployment of highly integrated RF front-ends for evolving mmWave applications," using an abbreviation for millimeter waves.
GlobalFoundries will produce the technology on 300mm wafers at a factory in East Fishkill, N.Y., which was included in its acquisition of IBM's Microelectronics unit in 2015. Over 27 billion such chips have been shipped since the technology entered production in 2008, the company says.