More than 65 percent of substrates used in fabricating switches for handsets are SOI based, according to the industry research firm Yole Développement. This shows the massive adoption of RF SOI for this booming electronic market experiencing double-digit growth. Soitec, the world’s leading manufacturer of SOI wafers, says that this shows that SOI-based technologies are now mainstream for manufacturing switches and antenna-tuners, key RF components used in all cell phones and tablet computers.
An RF SOI substrate has an active layer on which CMOS transistors are built, isolated from a high-resistivity silicon base layer. This reduces noise and interference, helping the finished die reach its target performance in terms of signal integrity, handling RF power and integration density. SOI technologies enable devices to reach a figure of merit for on-series resistance and off-equivalent capacitance (Ron.Coff ) below 200 fs (femtoseconds) with potential for further reduction. This directly relates to improved device performance and smaller die size.
On the strength of recent demonstrations, Soitec indicates that power amplifiers will likely be the next RF components based on SOI. The technology enables highly tunable amplifiers to address multi-region requirements on a single platform. In addition, the RF SOI substrates offer a path towards further integration, such as more mixed-signal and digital content.