ST’s innovative RF Silicon on Insulator (SOI) technology solutions enable the design of a full range of advanced RF Front-End Modules (FEMs), including modules for 5G technology.


Radio Frequency Front End Modules: a critical block in connected devices The RF Front-End Module is one of the most complex and critical designs in 4G LTE-A and 5G smartphones and base stations. Acting as an interface between the antenna and RF transceiver, the FEM integrates the RF components required for analog performance, such as multiple RF switches (used in both Tx and Rx paths), Low Noise Amplifiers (LNAs), Power Amplifiers (PAs), and antenna tuners.


The growing use of multiple antenna elements (or high order MIMO, Multiple-Input Multiple-Output) and multiple bands combined with carrier aggregation requirements have raised 5G FEM complexity and integration, thereby increasing RF silicon content in the latest smartphones and RF infrastructures.   Leveraging its strong know-how in Silicon-On-Insulator technology, ST developed a complete RF-SOI technology portfolio that includes H9SOIFEM and C65SOIFEM nodes. ST’s RF-SOI technology is a specialized process, optimized to perfectly meet the demanding analog RF performance and integration requirements of RF Front-End Modules for 4G, 5G, 2.4-5 GHz RF connectivity and Narrowband IoT devices, also known as LTE Cat NB1.   H9SOIFEM technology: the ideal solution for compact RF Front-End Modules The key applications of H9SOIFEM technology include 4G LTE-Advanced and 5G Sub-6 GHz RF FEMs with a focus on switch performance and RF FEM integration. H9SOIFEM technology also addresses the requirements of RF FEMs for 2.4 to 5 GHz and Narrowband IoT devices. The H9SOIFEM process is built on a 130-nm technology node and is manufactured on 8-inch wafers.


This process supports multiple active devices, such as 2.5 V thick Gate Oxide (GO) Metal-Oxide-Semiconductors (MOS) for standard cells and IOs,  2.5 V MOS optimized for RF switches, 1.2 V thin GO MOS optimized for LNAs, and high breakdown-voltage N-type Lateral Drain Extended MOS (NLDMOS) optimized for PAs in order to address all key RF components. The process also offers a choice of passive components, such as high-current and high-Q factor inductors, high-value poly resistors, MIM (Metal-Insulator-Metal) and MOM (Metal-Oxide-Metal) capacitors, RF diodes and RF varactors.   In order to ensure performance and flexibility despite process complexity, multiple back-end stack options are available, including the possibility to implement a top thick copper layer for improved transmission lines and inductance performance.

H9SOIFEM RONCOFF evolution over multiple generations

RONCOFF factor of merit

  • Switch MOS layout optimized for best RON x COFF
  • Low RON for low insertion loss
  • Low COFF for high isolation


C65SOIFEM technology: for optimized 5G RF FEMs in the Sub-6 GHz band C65SOIFEM is optimized for LNA performance across the entire 5G Sub-6 GHz bands, with the key added value of integrating a switch capability.   The C65SOIFEM process is built on a 65-nm technology node and manufactured on 12-inch wafers. It includes a low-noise, high-speed 1.2 V MOS (with fMAX = 200 GHz) optimized for 5G Sub-6 GHz band. This device addresses the increasing demand of LNAs, in both receiver diversity and the main antenna path, driven by 4 x 4 MIMO and multi-band requirements. As a key benefit, C65SOIFEM technology enables the integration of LNAs and switches, as required by most 5G UHB Rx FEMs.   The process also features an extended set of options for active devices (including a 2.5 V thick GO MOS optimized for RF switch, 1.2 V thin GO MOS optimized for LNA in the Sub-6 GHz band) and passive components (including spiral inductor, RF diodes, MOM capacitors, high value poly resistors). The back-end of line stack is full copper, for low-loss transmission lines and high-Q inductance.

C65SOIFEM NMOS FT vs VGS (Si measurements VS model)

ST value as RF-SOI technology partner

  • Supplier of innovative best-in-class RF-SOI technologies enabling a full range of 4G & 5G RF FEMs
  • Enabling design flexibility through multiple process options
  • Experienced supply chain handling billion of units per year
  • Dedicated customer support
  • Assembly, packaging, testing services

Key applications

  • RF switches and tuners
  • Low noise amplifiers
  • Power Amplifiers
  • Monolithically Integrated RF FEMs (Switches, LNAs, PAs, Passives)

High-performance RF devices and top-class manufacturing

  • H9SOIFEM: low RONCOFF, high PMAX for high-performance 4G & 5G RF switches and antenna tuners, multiple back-end stack options for the best performance/cost trade-off
  • C65SOIFEM: fMAX at 200 GHz, low noise figure, 1.2V MOS for Sub-6 GHz LNA and integrated switch, full copper back-end

Complete and flexible design platforms for all applications

  • 1.2 V MOS and 2.5 V MOS optimized for respectively LNAs & switches
  • High BV NLDMOS for PA (H9SOIFEM)
  • Choice of passives (incl. high Q factor inductors, high value poly resistors, capacitors)
  • High resistivity and trap rich substrate options
  • Optimized metal stack options, including thick copper for low-loss transmission lines and high Q inductances



Radio Frequency (RF) Front-End Module



4GスマートフォンやWi-Fi(IEEE 802.11ac)などの高速通信の新しい規格では、データ・スループットを増やす目的で40もの異なる周波数帯域を使用します。そのため、最新の通信機器はRFフロントエンド回路の増強が必要で、従来のディスクリート部品を使用したアプローチでは全体のサイズが非常に大きくなります。





H9SOI FEM : STのRFフロントエンド・モジュール向けRF-SOIソリューション

2012年、STは、これらの経験を基にH9SOIプロセスをさらに最適化し、最先端の完全統合されたRFフロントエンド・モジュールの開発を可能にする、専用のH9SOI FEMプロセスを開発しました。

競争力に優れたH9SOI FEMプロセスは、従来の技術よりも小型かつ高性能のRFフロントエンド・ソリューションを実現します。この新しいプロセスは、0.13µmと0.25µmのデュアルゲートMOSFETをベースにしており、1.2V MOS、2.5V MOS、および最適化されたNLDMOS(1) などの多数のデバイスをサポートし、RFフロントエンド・モジュールのあらゆるアプリケーション(スイッチ、アンテナ・チューニング、パワー・アンプ、低ノイズアンプなど)に対応します。

H9SOI FEMの性能上のメリット

STのRF-SOIは、アンテナ・スイッチおよびアンテナ・チューニング製品向けに優れたRon-Coff性能指数を提供し、堅牢な絶縁性と高いMOSブレークダウン電圧を維持しつつ、非常に高い性能を実現します。   Ron-Coff性能指数



最適化されたNLDMOSに厚膜銅配線層(Thick Copper Layer)を組み合わせることで、電力付加効率(PAE)とゲインが従来製品と比較して10%も改善された高効率パワー・アンプを実現できます。


さらに、H9SOI FEMプロセスは、安全マージンを持って5GHzの設計が可能なしきい値周波数で超低ノイズ指数(GO1 NMOSで0.2 dB)を維持できるため、非常に高性能なLNAを実現できます。

H9SOI FEMの製造上のメリット

STは、H9SOI FEMプロセスにおいてマスク数を削減し、プロセス・フローを簡略化しました。マスク数とプロセス・ステップ数を減らすことで、従来技術よりもリード・タイムを全体で25%削減しています。この新しいRF-SOIプロセスにSTの製造能力を組み合わせることで、顧客の非常に厳しい要求にも最短の開発期間でサポートします。

(1)NLDMOS : N type Lateral Drain Extended MOS(N型横方向拡散MOS)

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