The foundry market is a customer service oriented business. This is very evident in the number of providers and the services they offer. In order to have a well-rounded portfolio of products, foundry suppliers are even offering services in smaller, niche markets. One example of this is the growth in the number of foundries now offering silicon germanium (SiGe) process technologies.

When business was booming in 2000, the demand for high-performance, low-power technology became even more evident. Foundries--such as IBM Corp.'s Microelectronics Division and Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC)--stepped up to the plate by offering a SiGe foundry process as a very cost effective solution.

Today, there are even more suppliers jumping into this market. Germany's Communicant Semiconductor Technologies AG, a new, dedicated foundry, was established to focus primarily on SiGe BiCMOS processes. Even Singapore's Chartered Semiconductor Manufacturing Pte. Ltd.--known for its expertise in RF CMOS and mixed signal--will be adding SiGe to its offerings in order to provide its customers with more options.

Semico believes the SiGe market will grow rapidly from 2002 thru 2006. This technology has been available for quite awhile, but there are now more applications that require its performance level. In fact, SiGe is quickly growing in popularity for high-speed, low-power applications.

The three primary markets for SiGe products are cellular base stations and handsets, optical networking and disk drives. SiGe will only replace a portion of the RF components for each of these individual markets. However, even at that, SiGe revenues will have a compound annual growth rate (CAGR) of 49%. Units will grow at a 55% CAGR. Unit growth is slightly more elevated due to a decline in average selling price during the forecast time frame.

What is SiGe?

SiGe may be the next "big thing" in technology, but what is it? Germanium doped silicon is deposited on a silicon substrate. Originally, deposition of this material required specialized processing techniques, such as MBE (molecular beam epitaxy). However, SiGe film can now be grown using UHV CVD (ultra-high-vacuum chemical vapor deposition) tools or in standard epitaxial reactors with SiGe chemistry.

SiGe is used in bipolar transistors, either as a simple transistor circuit or as the bipolar segment of a BiCMOS chip. In BiCMOS applications, all of the standard CMOS processing techniques can be used before and after the SiGe is deposited. Deposition of SiGe has become just one more processing step added to traditional CMOS devices.

The device type determines at what point in the process flow the SiGe layer is deposited. In a simple bipolar transistor, the SiGe would be deposited as one of the first layers. In BiCMOS, the location of the transistor layer in the process flow determines when the SiGe is deposited on the wafer.

Germanium makes faster, more power efficient transistors, as well as improving noise characteristics when compared to standard silicon transistors. The process technology has evolved to the point where it is relatively easy to incorporate SiGe into a standard CMOS facility. When SiGe is added to a mature silicon process it will enhance the bipolar performance to the point where it is competitive with a much more "advanced" pure silicon process.

SiGe vs. other technologies

For example, the deposition of SiGe in a 0.35m silicon BiCMOS device could enhance the performance to the point where it is comparable to a 0.13m pure silicon BiCMOS process. At that point, the additional cost of the SiGe is offset by the cost of the higher technology in the silicon BiCMOS.

SiGe's competition at the low end (2.4GHz and below) includes RF CMOS as well as silicon BiCMOS. SiGe provides much better performance trade-off opportunities for designers to optimize noise, gain, linearity, and power consumption over both RF CMOS and BiCMOS.

SiGe is competitive in RF performance for mobile communication systems in the 1- to 2.4-GHz frequency range, since it offers additional integration potential and is less expensive to process than gallium arsenide (GaAs).

At higher frequencies, between 5- and 100-GHz, pure silicon BiCMOS solutions are not available and SiGe must be used. Cellular, wireless and optical communication systems will all reach the frequency range that requires SiGe technology.

The SiGe foundry players

SiGe companies are very candid about what the potential for this market is. During interviews with players in this market, it became quite clear that continuing technological advances make it difficult to distinguish where the limits to BiCMOS, RF CMOS and SiGe BiCMOS will be. This is an extremely competitive market, with advantages and disadvantages evenly distributed across technologies. While SiGe seems to have been label a "niche" market, in this case, the niche appears to have great potential.

IBM has been at the forefront of SiGe technology since 1982, and was the first company to broadly manufacture SiGe technology. IBM has now moved it from the laboratory to the marketplace and offers its manufacturing services as a part of its foundry service program.

TSMC claims to be the first pure-play foundry to offer SiGe BiCMOS technology. TSMC offers a 0.35-micron SiGe BiCMOS today and expects to have a 0.18-micron SiGe BiCMOS ready by late 2002.

Chartered will begin offering 0.18-micron SiGe BiCMOS manufacturing capabilities by the second half of 2003. Chartered is known for its extensive mixed-signal and RF CMOS technology and decided to broaden its offerings with the SiGe BiCMOS process in order to give companies more choices in high-performance, low-noise semiconductor technologies for the RF components of system-on-chip (SOC) applications.

Under a non-exclusive agreement through IMEC's Industrial Affiliation Program, Chartered is licensing IMEC's 0.18-micron SiGe-based bipolar module, along with the test chip structures and bipolar model.

And last but certainly not least, it is interesting to note that a small fab startup in Frankfurt, Germany, named Communicant offers SiGe. The company plans to begin production in the first quarter of 2004. The company's SiGe:C (carbon) is licensed from the Innovation for High Performance (IHP) Microelectronics Institute in Germany, with CMOS processes from Intel.

In addition to the CMOS licensing, Intel has invested in this foundry and has production allocation in the fab. Although Communicant has not revealed the specific breakdown of investment dollars by source, it has been reported that Intel is guaranteed a 20% share of capacity, with an option for a further 10%.

Foundry suppliers continue to expand services and remain flexible as the semiconductor market cycles through technologies, economic ups and downs and product lifecycles. This is a good sign that the foundry market is alive and well, and here to stay.