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|Development of a SiGeC Heterojunction Bipolar Transistor for|
|Ultra-high-speed/High-frequency Communication LSIs|
|- Ultra-high maximum oscillation frequency of 174 GHz -|
Japan, December 5, 2001 - Hitachi, Ltd. (NYSE:HIT)has developed
a prototype SiGeC heterojunction bipolar transistor (HBT) by using selective
epitaxial growth of a mixture of silicon (Si), germanium (Ge) and carbon
(C), and has achieved the world's fastest device performance; cutoff
frequency 1) of 124 GHz and a maximum oscillation
frequency 2) of 174 GHz. As SiGeC HBT features
little change in performance after high temperature processing, it is
well suited to application in bipolar CMOS (combination of HBT and CMOS)
device technology, which is expected to be the most promising candidate
for next generation communication LSIs. The high-speed performance developed
is expected to accelerate the application of the bipolar CMOS to transmitter/receivers
in ultra-high-speed communication systems.
The demand for large-capacity data transmission in optical and mobile communication systems is increasing with the rapid proliferation of the Internet and cellular phones. Thus, a significant improvement in high-speed performance is being required of LSIs (Large Scale Integrated Circuits) embedded in transmitters and receivers for communication systems. Bipolar CMOS (BiCMOS), a combination of the ultra-high-speed HBT and the mid-to-low speed signal processing CMOS (Complementary Metal-Oxide Semiconductor), is currently considered a viable solution to the above-mentioned requirement, and research is being focused on this device. Although, SiGe HBTs can operate at a high speed alone, a rapid deterioration in performance occurs due to heat-treatment when integrated with the CMOS, resulting in the lower performance than expected. Thus, SiGeC has been receiving much attention as a new material suitable for BiCMOS due to its high tolerance to heat treatment 3). Until now, however, it was not possible to fabricate a SiGeC HBT with a self-aligned structure 4) by using selective epitaxial growth, and thus high-speed performance could not be obtained.
Given this background, Hitachi developed a high-speed SiGeC HBT technology suitable for BiCMOS and achieved the world's fastest performance. The two technology developed are as follows:
As a result, the following performances were achieved:
Using this technology, it will now be possible to integrate high-speed HBT and 0.1m CMOS. This ultra-high-speed high-functional device technology is expected to play an important role in supporting next-generation information technology such as multi-media services offered by next-generation backbone transmission systems, large-capacity radio communication systems, and intelligent traffic control systems using millimeter-wave bands.
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|WRITTEN BY Corporate Communications Division