BiCMOS

Technology for high-performance
optical and RF ICs

The demand for new data centers has surged in recent years, fueled by growing digitalization and the uptake of artificial intelligence (AI), which is expected to continue accelerating. Optical solutions play a key role in interconnecting data center resources, such as servers, switches, and storage units. They also facilitate short-reach GPU-to-GPU connections within AI clusters. Overall, the increasing data rates are driving the demand for higher-performing optical ICs.

Low Earth orbit (LEO) satellite constellations, under deployment to provide fast broadband connectivity around the world and 5G networks are driving the need for high-performance RF devices. Additionally, new microwave applications, such as automotive radars, LAN RF transceivers (60 GHz), point-to-point radio (V-band / E-band), and security or instrumentation solutions, require RF performance in challenging operating conditions, with greater chip integration, reduced power consumption, and optimized costs.

To support these demands, ST is investing aggressively in BiCMOS technology, which provides the optimal answer. Today, ST’s BiCMOS technology can be found in the most advanced optical modules, LEO satellite terminals, and wireless base stations worldwide, as well as in automotive radars and instrumentation solutions.

BiCMOS and silicon photonics

BiCMOS55X is ST’s latest generation of BiCMOS technology. Providing unprecedented low noise figures and excellent linearity, it is the ideal technology to address 200 Gbps per lane and 400 Gbps per lane transimpedance amplifiers (TIA) and laser drivers.

ST’s BiCMOS linearity plays a key role in facilitating linear pluggable optics (LPO), optimizing the bill of material of optical modules in terms of power efficiency and cost.

Integrated with ST’s silicon photonics technology, silicon germanium BiCMOS technology enables the development of most components in optical modules, offering the performance and power efficiency required in the next generation 800 Gbps and 1.6 Tbps optical interconnects.

BiCMOS: the best of two worlds

Silicon germanium (SiGe) BiCMOS combines the strengths of two different process technologies into a single chip. Bipolar transistors offer high speed and gain, which are critical for high-frequency analog sections, whereas CMOS technology excels for constructing medium-complexity, low-power logic gates.

By integrating the RF, analog, and digital parts on a single chip, ST’s SiGe BiCMOS technology drastically reduces the number of external components while optimizing power consumption.

Typical cellular base station or point-to-point radio receiver

Typical optical fiber and active optical cable module

ST’s BiCMOS process technology today offers a level of performance attainable in the recent past only with more expensive technologies such as gallium arsenide (GaAS), while providing a significant advantage in integration.

Compared to bulk CMOS, the BiCMOS heterojunction bipolar transistor (HBT) enables a much higher cutoff frequency at a given technology node. To reach similar frequency, bulk CMOS designs have to use much smaller process nodes, forcing compromises on the design and leading most of the time to overall lower performance and higher cost.

Thus, thanks to its better cost profile compared to the alternatives, ST’s BiCMOS enables a wide range of applicative use cases.

ST leads in BiCMOS process technology

With strong know-how in design, architecture and process integration, ST offers a leading-edge SiGe BiCMOS technology, enabling the design of high-performance RF ICs. The B55 and B55X technologies are produced in a 300 mm wafers production facility in Europe ensuring a high-volume supply.

The most advanced technologies

Designed with a true mixed-signal approach in mind, ST’s BiCMOS process family provides all the technologies for optimal product design, including:

A wide range of MOS and Bipolar transistors
V-PNP, DMOS, Dual-Gate Oxide MOS
SiGe-C HBT for the best speed-to-noise ratio
Millimeter-wave dedicated metal layers (thick copper) for high-Q inductance and low-loss transmission lines

Combined with high-resistivity substrate and deep trench isolation techniques, ST's BiCMOS process offers best-in class isolation for effective integration of RF blocks.

Through-silicon via technology is an integral part of the development roadmap, poised to offer customers a unique and distinctive solution in the market.

A complete offering for optimal design and manufacturing

ST’s BiCMOS design platform is supported by leading-edge CAD tools in a complete and effective design flow, including a very accurate set of simulation models. Its effectiveness has already been proven by many customers on successful IC designs.

ST supports different business models for its BiCMOS technology, from a pure foundry service to a range of services, including packaging and testing, for ASIC design, development, and support. This flexibility allows ST to provide the most appropriate answer to meet any customer requirements.

ST’s extensive experience on a wide range of analog, RF, and digital IPs, developed on its BiCMOS technology eases customers’ product design and ensures fast time-to-market.