Inside Track with Duncan Pilgrim, Vice President of Marketing, Peregrine Semiconductor

Low insertion loss enables lower power-amplifier (PA) drive and thus lower energy consumption and higher output efficiency. High isolation prevents signal contamination between different RF signal paths. Additionally, high linearity lends itself to support higher-order modulation schemes without signal degradation.

If an RF SOI technology utilizes a mainstream CMOS process flow, it offers the bonus of leveraging a standard CMOS process. In doing so, it can add high scalability and fabrication capability factors, which are not otherwise accessible with RF integrated-circuit (IC) technology. CMOS also is recognized for its manufacturing repeatability, which reduces end-product performance variability.

Unlike other technologies, RF SOI enables these unique RF properties to be integrated along with analog, digital, and mixed-signal capabilities. The unique benefit of RF SOI is that it can accommodate multi-domain capabilities all in one chip. This superior level of integration delivers a smaller form factor, higher flexibility/configurability, higher reliability, and better performance.

JJD: What limitations does SOI technology have, and what applications would you expect not to see in SOI technology?

DP: RF SOI is not ideally suited for very high-power applications, such as wireless-infrastructure or PA applications. There, RF SOI technology is complementary to high-power technologies like gallium nitride (GaN) and laterally diffused metal-oxide semiconductor (LDMOS).  However, the RF SOI technologies that use a sapphire substrate have excellent high-frequency capabilities. 

Sapphire is an almost perfect insulator. As such, it allows the use of traditional monolithic-microwave-IC (MMIC) design techniques, which have traditionally been used on GaAs technologies. The same benefits of SOI at lower frequencies can now be realized at these high frequencies. Simple capabilities, such as high electrostatic-discharge (ESD) performance and integrated control interfaces, also can be featured in products at millimeter-wave frequencies.  As we see the key requirements for fifth-generation (5G) rollout, I think this capability will become increasingly important.

JJD: How has RF SOI been transformed in the past few decades?

DP: RF SOI was once considered an exotic niche technology, which couldn’t achieve the performance or cost structure required to compete with technologies like GaAs and silicon germanium (SiGe). Yet innovation in the three key areas of process, substrate, and design/IP have enabled it to achieve the RF performance required to compete with the incumbent technologies. As with all CMOS-based processes, RF SOI’s cost structure improved as volumes increased.

In 2009, for example, we hit a major milestone for our handset switch products when the UltraCMOS 5 technology beat the incumbent GaAs technology on all performance metrics. At that point, RF-SOI quickly became a widely accepted RF technology. It is now uncommon to find an antenna switch that utilizes GaAs. RF SOI enables many new products for which other technologies are not suited.

JJD: What applications does RF SOI technology best fit, and how are those applications adopting the technology?

DP: SOI is the best fit for RF applications that need high-end RF performance, configurability, high reliability, and a future need for integration.  Cost can never be ignored and, fundamentally, RF-SOI is a CMOS technology. It therefore benefits from the enormous manufacturing scale that CMOS brings. The additional advantage is that it doesn’t utilize the most advanced technology node.  As the complexity of end applications increases, the benefits of using an RF SOI process also rises. We expect this to continue as the world becomes a more connected place.

JJD: Where do you see RF SOI fitting in with the explosion of wireless devices and the Internet of Things?

DP: Assuming that all things are connected via the Internet, the critical requirements become size and power. The integration and scaling capability derived from SOI technology enables product and solution design at a performance level that would be very difficult to reach with any other technology. For example, our all-CMOS RF front-end product, UltraCMOS Global 1, boasts a level of integration and RF performance that is not feasible with other technologies. The core capability of the latest RF SOI technology for the handset market has very broad applicability across other applications.

In addition to Wi-Fi and small cells, it can be leveraged into adjacent markets like infotainment and connectivity systems for the automotive market. Currently, the primary industry focus for RF-SOI is on the mobile market. However, RF SOI technology supports many other end markets, such as wireless infrastructure, test and measurement, and automotive. These markets also are pushing for higher levels of performance and integration, and RF SOI is ideally suited to drive these demands.

JJD: We saw the recent news regarding Murata’s acquisition of Peregrine Semiconductor. What were the key factors in Murata’s interest in Peregrine?

DP: This acquisition will combine Murata’s mobile RF-module capabilities with Peregrine’s RF-front-end products. Peregrine invented RF SOI, has led its development for 20-plus years, and accomplished a large number of industry firsts. As a result, I would say that the acquisition will deliver to Murata advanced RF-front-end capabilities and the world’s best SOI process technology. RF SOI is a key enabler for the growing integration of mobile technologies.

The radio requirements of smartphones and other wireless devices continue to grow more complex. This complexity could be best solved with silicon technology. Peregrine supplies devices to many wireless markets including smartphones, test and measurement, automotive, public-safety radio, and wireless infrastructure. Peregrine also will give Murata a strong portfolio of Intellectual Property Rights (IPR), covering a wide range of proprietary RF SOI front-end solutions and techniques.