Ultrahigh-Speed InP/InGaAs DHBTs with Very High Current Density

Minoru IDA  Kenji KURISHIMA  Noriyuki WATANABE  

IEICE TRANSACTIONS on Electronics   Vol.E86-C    No.10    pp.1923-1928
Publication Date: 2003/10/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on Heterostructure Microelectronics with TWHM2003)
heterojunction bipolar transistor (HBT),  indium phosphide,  graded base,  

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We describe 150-nm-thick collector InP-based double heterojunction bipolar transistors with two types of thin pseudomorphic bases. The emitter and collector layers are designed for high collector current operation. The collector current blocking is suppressed by the compositionally step-graded collector structure even at JC of over 500 kA/cm2 with practical breakdown characteristics. An HBT with a 20-nm-thick base achieves a high fT of 351 GHz at high JC of 667 kA/cm2, and a 30-nm-base HBT achieves a high value of 329 GHz for both fT and fmax at JC of 583 kA/cm2. An equivalent circuit analysis suggests that the extremely small carrier-transit-delay contributes to the ultrahigh fT.