Peregrine Semiconductor, a leading supplier of high-performance RFICs, has been making impressive market gains, having shipped over half a billion devices including their low-loss, high-isolation switches and low-phase-noise PLLs. The company’s proprietary silicon-on-sapphire technology, known as UltraCMOSTM, has generated significant industry activity in RF SOI (silicon-on-insulator) process and technology development. Recently, the company has demonstrated that its technology can be expanded from high power RF switches and tunable components to multi-mode power amplifiers and highly integrated devices targeting configurable RF cellular front ends.
The company is now aggressively developing its capabilities and forming strategic alliances to enable the highest-levels of integration for 4G multi-band mobile wireless devices while maintaining their best in class performance, scaled to CMOS based economics.
One component to this initiative is their exclusive joint development and foundry agreement with IBM Corp., announced in May, providing Peregrine access to key process technology and manufacturing capacity. The two companies will jointly develop Peregrine's next-generation, silicon-on-sapphire technology, based on a 180-nm process on 200-mm wafers to be manufactured within IBM's 200-mm fab in Burlington, Vt. Migration to 200mm wafers facilitates the evolution of the process to advanced 180nm, 130nm and 90nm nodes. It also provides access to advanced manufacturing toolsets and enables significantly expanded digital integration capability. Further, the agreement with IBM provides, through its world-class Technology Alliance partners, unprecedented levels of manufacturing capacity and a robust supply chain.
The arrangement should allow Peregrine to expand its current product offerings of RF switches, DSAs, PLLs, prescalers, etc. to also include highly integrated RF CMOS devices that incorporate PAs and switch throws. Peregrine reports that it has built and measured switch, tunable capacitors and power amplifiers using the IBM 7RF SOI process and UltraCMOS SOS at.18um, concluding that UltraCMOS technology provides a superior RF platform for a monolithic RF front end. The exclusive relationship with IBM will see product launch in 2011 with initial devices being sampled to key customers.
Data-driven mobile wireless devices will likely call for new complex RF front-end architectures that support high throw count switches, multiple switch paths, multi-mode PAs, increased filter counts and broadband and/or multiple antennas. Demand for such devices will require high volume production and considerable attention to lowering component counts and costs.
Peregrine believes it has the technology in place to take on these challenges. From Peregrine’s perspective, UltraCMOS is a more systematic path to implementing monolithic IC solutions with high-performance, tunable (and reconfigurable) integrated components, providing an advantage over the “multiple technologies” approach also known as optimum technology matching (in modules), taken by other integrated device manufacturers (IDMs). The multiple technologies approach requires the development of various technologies as well as the multi-chip module integration and may be vulnerable to supporting multiple technology supply chains and fabs.
UltraCMOS supports FET stacking with low-loss, highly insulating substrates, which allows efficient power handling using low power devices. In addition, the process supports high linearity and voltage handling, low power, excellent RF connectivity, low capacitance (for fast switching speeds and higher operating frequencies), good thermal conduction and temperature stability, high electrical isolation, low leakage currents and high Q passive components. In addition, this single process supports all functional blocks, flip-chip packaging, to digital integration at CMOS cost metrics, to help achieve the monolithic front-end vision. In comparison, Silicon-on-Insulator (SOI) has limited linearity and voltage handling, poor thermal conductivity, electrical isolation, high leakage currents and low Q passives.
UltraCMOS – Enabling Moore’s Law in RF Front End
Silicon-on-sapphire is a type of silicon-on-insulator (SOI) technology, formed by depositing a thin layer of silicon onto a sapphire wafer. This in turn creates an insulating sapphire substrate, which has certain advantages over bulk silicon and gallium arsenide (GaAs) in RF applications. Moving to increasingly smaller process nodes allows Peregrine to increase the gross die per wafer while improving performance.
Before joining forces with IBM, fabless Peregrine's manufacturing model relied on four CMOS foundry suppliers, MagnaChip, Oki/Rohm, Sapphicon and UMC for qualified 0.5um, 0.35um and 0.25um processes on 150-mm substrates with 200 mm wafers in development. The company’s sapphire supply came from three qualified multinational suppliers. Peregrine’s device volume consumes ~3% of the worlds sapphire wafer demand. This high growth demand (projections call for 200 million units shipped in 2010) is expected to help drive down costs. For a particular switch product built on 150 mm diameter wafers, Peregrine shipped 7,000 die per 0.5um CMOS and 9,000 die per 0.25um CMOS. The company expects to ship over 30,000 die per wafer on 200 mm diameter, 0.18um CMOS.
Peregrine refers to the new 180-nm silicon-on-sapphire process as its Step7 technology. The company claims Step7 produces devices that are 50 percent smaller, half the insertion loss with 100 times better linearity. The technology is expected to propel a new class of RF devices, including high-power switches and tunable components, said Rodd Novak, chief marketing officer for Peregrine.
Peregrine was founded in 1990 by former researchers at the Naval Ocean Systems Center in San Diego to commercialize silicon-on-sapphire. The technology was invented in 1963 at North American Aviation (now Boeing), but never made it outside the lab, according to Peregrine. HP, RCA and others developed silicon-on-sapphire chip technology for niche applications in the 1970s. But for the most part, the technology was exotic, expensive and difficult to make. Even Peregrine experienced difficulties in the early years until a turning point came in 2003, when the company was able to scale the technology, thereby gaining some traction in RF applications.
Silicon-on-sapphire began life in rad-hard space and military products over 25 years ago. Sapphire is a superior insulator compared to SOI, and it has finally become cheap enough for commercial deployment,'' said Will Strauss, president of Forward Concepts Co. (Tempe, Ariz.). As a result, Peregrine's revenues have steadily increased through the semiconductor market.