Soitec has introduced its eSI90 substrate, the newest high-end wafer in its radio-frequency silicon-on-insulator (RF-SOI) product family. The eSI90 is designed to improve the RF performance of mobile communication components such as high-linearity switches and antenna tuners that are integrated in high-end smart phones for LTE Advanced networks using carrier aggregation. This enables multiple LTE carriers to be used together, providing higher data rates to enhance user experience.

The new wafers are Soitec's second generation of eSI(TM) substrates, based on engineered high-resistivity (HR) substrates. Today, eSI substrates have been widely adopted by leading RF semiconductor companies to address device cost and performance needs for the 3G and 4G/LTE mobile wireless markets. Soitec's eSI90 product exhibits higher effective resistivity than first-generation eSI wafers, enabling a 10-decibel (dB) improvement in linearity performance in RF front-end modules to address the stringent new requirements of LTE Advanced smart phones.

Soitec developed a new metrology standard, the Harmonic Quality Factor (HQF), to predict the expected RF linearity of finished ICs. HQF correlates with the second harmonic distortion value of a coplanar waveguide deposited on the substrate. The new eSI90 wafers' HQF maximum value is set to -90 decibel-milliwatts (dBm) compared to -80 dBm for first-generation eSI substrates.

The lower limit on eSI90 wafers enables chip makers to take advantage of design and process improvements to increase the RF performance of their semiconductor designs and to meet MIMO (Multi-Input Multi-Output) and Carrier Aggregation LTE Advanced requirements, providing faster data connections. The new eSI90 substrates are already under evaluation at multiple leading chipmakers and foundries. Production-ready samples are now available from Soitec.