Over 300 GHz f/sub T/ and f/sub max/ InP/InGaAs double heterojunction bipolar transistors with a thin pseudomorphic base |
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Authors: | Ida M Kurishima K Watanabe N |
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Affiliation: | NTT Photonics Labs., NTT Corp., Kanagawa, Japan; |
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Abstract: | Describes 150-nm-thick collector InP-based double heterojunction bipolar transistors with two types of thin pseudomorphic bases for achieving high f/sub T/ and f/sub max/. The collector current blocking is suppressed by the compositionally step-graded collector structure even at J/sub C/ of over 1000 kA/cm/sup 2/ with practical breakdown characteristics. An HBT with a 20-nm-thick base achieves a record f/sub T/ of 351 GHz at high J/sub C/ of 667 kA/cm/sup 2/, and a 30-nm-base HBT achieves a high value of 329 GHz for both f/sub T/ and f/sub max/. An equivalent circuit analysis suggests that the extremely small carrier-transit-delay contributes to the ultrahigh f/sub T/. |
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