Thread: I apologize in advance for the length of this post, but there seems to be very strong interest in SiGe amongst participants in this thread, I am posting the text of an article that might be useful.
IBM Plans to Challenge GaAs
A SiGe product line scheduled for next year is key to Big Blue's strategy for establishing a presence in the market for communications semiconductors.
Marie Meyer
Compound Semiconductor Magazine, Volume 3 Number 4, July/August 1997
IBM Microelectronics is gearing up for a new campaign to promote its SiGe technology as a commercially viable process. In doing so, it plans to challenge GaAs IC makers in virtually every high volume application. IBM is hoping that its unique ability to manufacture SiGe-based bipolar and BiCMOS circuits in large volumes will enable it to establish greater credibility as a supplier of semiconductors for communications systems - a red-hot market which Big Blue has largely missed out on.
The First Customers
On June 19 IBM announced that it had signed an agreement with Nortel for the development of SiGe ICs for high-speed telecommunications and wireless applications. Nortel will design prototype microchips and IBM will manufacture the devices.
"SiGe-based devices can move information across a network at speeds traditionally considered to be beyond the reach of silicon technology," said Robert Hadaway, director, technology access and applications, Nortel "Nortel's prototype microchips will be used in fiber transport products as well as for several high-speed cellular and personal communications services' (PCS) wireless applications. Our objective is to work towards developing advanced devices at commodity-level costs."
Nortel is said to be designing the new chips already. Early prototypes will reportedly be manufactured and validated later this year.
IBM says Nortel is their second customer for its SiGe process. In May of 1996, they announced a collaborative effort with Hughes Electronics to prototype devices for potential applications in several Hughes divisions, including Network Systems, Aircraft, Telecommunications & Space, and Delco Electronics. (See CS 2(4), p. 19.) According to Ron Finnila of Hughes, that work is continuing, and he says that Hughes' interest "remains high". The SiGe circuits under consideration are still in the prototype stage, and at this point there is no public forecast for production will start. Finnila reports that an automotive collision avoidance system is one of several applications that are being investigated.
What about Analog Devices?
The Hughes and Nortel announcements are, in reality, the second introduction of IBM's SiGe plans. The first came in 1993 when IBM announced an agreement with Analog Devices to commercialize RF and mixed-signal SiGe circuits for wireless communications. There were also plans for high-speed SiGe circuits such as a 1 GHz digital-analog converter for multi-media telecom and datacom markets such as ATM/SONET and digital CATV. However, both parties to the deal apparently got cold feet, and the agreement was terminated before any chips were produced. There is no current active relationship between the two companies.
According to Ron Soicher, vice president of analog and mixed signal development for IBM Microelectronics, the Analog Devices agreement was "a little bit ahead of its time". In the two years since then IBM has increased it commitment to the SiGe process, raised its funding levels, and improved its "marketing savy" for communications semiconductors. He reports that IBM is "committed to building a business" on its SiGe process. As a result, IBM is putting in place a volume manufacturing capability for next year, and more announcements about deals with other electronics companies are planned for the very near future.
Targets
IBM's standard high volume ion-implant BiCMOS process is targeted at a maximum frequency of 18 - 20 GHz. The SiGe technology is being developed in bipolar-only and BiCMOS iterations, both with an fmax of around 50 GHz. According to Bernie Meyerson, who has led the IBM SiGe development program, at above 10GHz IBM employs a polyimide based backend process to lift transmission lines and passives well off the substrate to eliminate coupling and associated losses.
Soicher says that whereas IBM might be legendary for indulging in some pretty exotic bipolars, in the present case they have reduced the complexity because the potential applications don't require it. In the case of SiGe BiCMOS, he says, "we are trying to build a process profile that is very cost competitive and close to a standard BiCMOS, but is also 'super-charged' through the use of epi and the addition of the Ge in the base, as well as the implementation of deep trench isolation."
IBM's target markets include virtually all of the high volume applications where GaAs is currently thriving, with the possible exception of 900 MHz analog phones. For applications above 1.5 GHz, Soicher says, the high frequency and noise attributes give SiGe "compelling advantages over BiCMOS and GaAs in terms of cost, power dissipation and other features." Therefore, he says, "we want to go after the high volume GaAs sockets in digital cellular, GPS receivers, and high performance wireless LANs at 2.4 GHz and 5.2 GHz." Other possible applications mentioned include direct broadcast satellite (DBS) receivers at 11-12 GHz; global positioning satellite (GPS) receivers at 1.6 GHz; TV set-top box tuners at 1.2 GHz and above; collision avoidance radar at 24 GHz, as well as high-speed data communications circuits for standards such as SONET and ATM.
"I don't want this to be viewed as a technical curiosity, but as a commercial and highly manufacturable process" Soicher says. "That is why we have waited until we were well into our qualification processes before making announcements." He reports that the bipolar version is already qualified, and that IBM is in the process of qualifying the BiCMOS version. Both are run on the same high volume 8" lines are also used for IBM's standard BiCMOS and CMOS.
Can IBM Cut It In Communications?
IBM's historical strengths in semiconductors lie in the computing area. They are not known as a leader in the communications sector. Soicher says it will be necessary for them to earn some credibility in the field, perhaps by implementing SiGe designs into IBM products in the networking and communications field, as well as continuing to work with outside customers such as Hughes and Nortel. To that end, IBM plans to introduce its own line-up of merchant and captive SiGe BiCMOS circuits next year. The first captive application may be for 5.2 GHz wireless LANs which will be offered by another IBM division.
SiGe technology appears to be an important component of their strategy for establishing a presence in the communications area. They hope that it will give them an exclusive niche that will help to make up for their late entry into this sector. But it might be dangerous to have a too exclusive position, because buyers will likely be reluctant to make volume commitments to a new technology without having a qualified second source. Therefore IBM is encouraged to see that other companies are also pursuing their own SiGe R&D programs. "All of the major semiconductor companies that are active in communications today have SiGe projects, in varying levels of maturity" says Soicher. "We think that you will see, over the nest 2-3 years, a lot of these companies getting into the market."
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