SiGe RF ICs: Benefits & Key Manufacturers

Introduction : Commercialization of massive satellite constellations, automotive radar and 5G mmwave networks require high frequency technology. Silicon Germanium (SiGe) technology has been choosen for millions of consumer devices due to extreme high frequency performance of this compound semiconductors with the low cost, high yield manufacturing scale of standard Silicon.

What is a SiGe RF Device?

Standard Silicon CMOS struggles at very high radio frequencies due to electron mobility limits and parasitic noise.

Silicon Germanium (SiGe) solves this by introducing a thin layer of germanium into the atomic lattice of standard silicon to create a Heterojunction Bipolar Transistor (HBT). The addition of germanium creates an electric field that literally accelerates electrons across the transistor, drastically increasing the speed at which the device can switch.

Crucially, SiGe HBTs are typically combined with standard Silicon CMOS on the exact same chip. This technology is known as SiGe BiCMOS (Bipolar CMOS). It allows engineers to place high speed RF analog circuits and complex digital control logic on a single piece of silicon.

Key benefits of SiGe in RF

Following are some of the advantages of SiGe in RF engineering.

1. Offers unprecedented integration. SiGe allows engineers to put the RF front end, phase shifters, amplifiers and the digital control interface onto a single, highly compact chip. This massively reduces the Size, Weight and Power (SWaP) of the overall system.
2. The manufacturing yield is incredibly high, making SiGe significantly cheaper to produce in high volumes than GaAs or GaN.
3. SiGe HBTs possess incredibly high cutoff frequencies often exceeding 200 GHz to 300 GHz. This makes the material highly effective for FR2 mmWave applications, such as 28 GHz 5G networks. It is also absolute dominant technology for 77 GHz automotive collision avoidance radar.
4. In hybrid phased array antennas such as those used in modern satellite user terminals, the system must drive hundreds or even thousands of individual antenna elements. SiGe provides a highly power efficient way to implement localized beamforming, phase shifting and amplification at each antenna element while keeping the overall thermal footprint low.

Key manufacturers of SiGe RF Devices

Summary:

By merging the speed of compound semiconductors with the low cost and massive integration capabilities of silicon, SiGe RF ICs have made technologies like active phased array satellite internet, 5G mmWave phones and autonomous driving radar commercially viable for the everyday consumer.