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IBM Technical Journals

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Advancing the state of the art in high-performance logic and array technology

Award plaque by K. H. Brown,
D. A. Grose,
R. C. Lange,
T. H. Ning,
and P. A. Totta

High-speed silicon bipolar technology continues to meet the demands of integrated circuits for mainframe computers. IBM has developed an advanced bipolar logic and high-speed array technology for its Enterprise System/9000™ systems. This technology, code-named ATX-4, is composed of trench-isolated, double-polysilicon self-aligned bipolar devices, and has four fully planarized wiring levels with interlevel connecting studs. Chip fabrication has been implemented in 1-μm ground rules and is in full-scale manufacturing. ATX-4 represents a significant advance in providing higher-speed and lower-power logic at increased levels of integration compared with that of the ATX-1 technology used in previous generations. An overview of the design and integration of ATX-4 is discussed.

Originally published:

IBM Journal of Research and Development, Volume 36, Issue 5, pp. 821-828 (1992).


This paper describes the design and modifications made to optimize bipolar technology for use in IBM Enterprise System/9000® mainframe computers. The resulting device, code-named ATX-4 and constructed with 1-μm ground rules, was a high-reliability, high-performance bipolar transistor with low power and planarized interconnections. Despite the advances made to the bipolar transistor technology, a decision was made to switch from bipolar to CMOS transistors in IBM mainframe computers because of the greater reliability of CMOS and lower system costs. [For details, see “IBM S/390 Parallel Enterprise Servers G3 and G4,” by G. S. Rao, T. A. Gregg, C. A. Price, C. L. Rao, and S. J. Repka, IBM Journal of Research and Development 41, No. 4/5, 397-403 (1997).]

An important alternative application for bipolar transistors with many of the ATX-4 features emerged at this time. A large market for high-speed SiGe-based heterogeneous bipolar transistors and SiGe BiCMOS developed for high-end telecommunications equipment. In 2005, “high-speed silicon germanium devices” were among the innovations cited when IBM received the 2004 U.S. National Medal of Technology.

Related paper: IBM S/390 Parallel Enterprise Servers G3 and G4 (JRD 1997) by G. S. Rao et al.

See the 2004 National Medal of Technology awarded to the IBM Microelectronics Division in 2005 and the IBM Press Release of the announcement.

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