BiCMOS Technology
The need for high-performance, low-power, and low-cost systems for network transport and wireless communications is driving silicon technology toward higher speed, higher integration, and more functionality. Further more, this integration of RF and analog mixed-signal circuits into high-performance digital signal-processing (DSP) systems must be done with minimum cost overhead to be commercially viable. While some analog and RF designs have been attempted in mainstream digital-only complimentary metal-oxide semiconductor (CMOS) technologies, almost all designs that require stringent RF performance use bipolar or semiconductor technology. Silicon integrated circuit (IC) products that, at present, require modern bipolar or BiCMOS silicon technology in wired application space include the essential optical network (SONET) and synchronous digital hierarchy (SDH) operating at 10 Gb/s and higher.
The viability of a mixed digital/analog. RF chip depends on the cost of making the silicon with the required elements; in practice, it must approximate the cost of the CMOS wafer, Cycle times for processing the wafer should not significantly exceed cycle times for a digital CMOS wafer. Yields of the SOC chip must be similar to those of a multi-chip implementation. Much of this article will examine process techniques that achieve the objectives of low cost, rapid cycle time, and solid yield.
INTRODUCTION
The history of semiconductor devices starts in 1930’s when Lienfed and Heil first proposed the mosfet. However it took 30 years before this idea was applied to functioning devices to be used in practical applications, and up to the late 1980 this trend took a turn when MOS technology caught up and there was a cross over between bipolar and MOS share.CMOS was finding more wide spread use due to its low power dissipation, high packing density and simple design, such that by 1990 CMOS covered more than 90% of total MOS scale.
In 1983 bipolar compatible process based on CMOS technology was developed and BiCMOS technology with both the MOS and bipolar device fabricated on the same chip was developed and studied. The objective of the BiCMOS is to combine bipolar and CMOS so as to exploit the advantages of both at the circuit and system levels. Since 1985, the state-of-the-art bipolar CMOS structures have been converging. Today BiCMOS has become one of the dominant technologies used for high speed, low power and highly functional VLSI circuits especially when the BiCMOS process has been enhanced and integrated in to the CMOS process without any additional steps. Because the process step required for both CMOS and bipolar are similar, these steps cane be shared for both of them.
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Love this valuable information, especially CMOS history. I was searching about CMOS and SiGe technologies to check a fact came online and ended up here, instead going further I read your post and it is helpfull. Thanks for sharing your knowledge. Analog Asic Design