Keywords BiCMOS technology, analogue/digital processing, analogue/digital converters, filters, ECL SRAMs
Start Date: 01-APR-85 (project 412), 15-NOV-88 (project 2430) / Duration: 44 months (project 412), 47 months (project 2430)
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The objective of the BICMOS project has been the development of a VLSI technology combining, on a single chip, high-density CMOS circuitry with bipolar circuitry of similar density, but better suited to specific tasks, such as high performance analogue circuits. The main effort has been on the technological side, in the development of methods which allow both bipolar and CMOS transistors to be made in compatible process steps, and in dimensions comparable to those obtained in CMOS-only technology. In parallel with the technological work, design methods for this specific type of circuit (mixing analogue and digital functions) have been under development, along with studies to determine, for various types of application, the most appropriate division of sub-systems between the two circuit techniques.
During the first phase of the BICMOS project (as project 412), a rather complex process, called BICMOS-1 (1.5 micron emitter width for bipolar devices combined with 1.5 1.2 micron CMOS transistors), was developed. Application studies of the mixed process resulted in the design of a number of digital and analogue functions. These functions were first simulated and implemented on silicon in the already-developed 2 micron process, BICMOS-0. Besides showing the strengths and weaknesses of the design tools in the analogue field, this allowed the quantitative evaluation of the advantages of a mixed process over plain CMOS, notably for drivers and analogue functions. As a first circuit demonstrator, a microprocessor-controlled "audio centre" (of about 20K transistor complexity) was successfully designed and processed at Philips in both BICMOS-0 and BICMOS-1. At the same time, target specifications for the performance of BICMOS-1 (570 MHz for CMOS toggle frequency and 5.2 GHz for bipolar transition frequency) for digital applications were met at Siemens.
A BICMOS-2 (1.2 micron feature size in CMOS and 0.9 - 1.2 micron in the bipolar part) was developed within project 2430, based on the integration of standard LDD MOS devices and self-aligned double polysilicon bipolar devices. At Siemens a bipolar transit frequency of 10 GHz was achieved. At Philips, isolated vertical pnp transistors with a transit frequency of over 1 GHz have been incorporated for analogue applications. A number of circuits have been designed and processed. Among them are:
The partners have further developed a BICMOS-3 technology aiming at a further improvement in performance of CMOS and bipolar devices, a reduction in process complexity and a CMOS packing density that is competitive with 0.7-0.8 micron CMOS technologies. In this process the following circuits have been designed and processed:
During the project (and as a result of it) it became clear that there is a market for BiCMOS IC products with an added value that more than compensates the somewhat higher intrinsic cost of the process.
At Philips, the BICMOS-0 process is running high-volume production of analogue bas-band video and audio ICs, and a derivative of BICMOS2 is ramping up in the factory for similar applications.
Siemens brought the BICMOS-3 to MSI maturity within the 4 MB DRAM 6" fab. Spin-off process modules from this process are used in high-precision analogue BiCMOS as well as high-speed bipolar processes.
Apart from the direct visibility of the project results in terms of processes in factories, the project has had a tremendous influence in the IC industry in terms of the level of experience obtained.
Ir K. J. Wouda
PHILIPS RESEARCH LABORATORIES
Prof. Holstlaan 4
NL - 5656 AA EINDHOVEN
tel: + 31/ 40-742937
fax: + 31/ 40-744657
PHILIPS RESEARCH LABORATORIES - NL - C
SIEMENS AG -
SEMICONDUCTOR GROUP - D - P
UNIVERSITÄT STUTTGART - D - S
MIKROELEKTRONIK GMBH - A - A
TRINITY COLLEGE DUBLIN - IRL - A
PHOENIX VLSI CONSULTANTS LTD - UK - A
INESC - P - A
BICMOS - 2430, December 1993
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html version of synopsis by Nick Cook