Improved RF Characteristics of InGaP/GaAs HBTs by Using Novel Ledge Coupled Capacitor (LCC) Structure

Naohiro TSURUMI  Motonori ISHII  Masaaki NISHIJIMA  Manabu YANAGIHARA  Tsuyoshi TANAKA  Daisuke UEDA  

IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.10   pp.2004-2009
Publication Date: 2003/10/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Heterostructure Microelectronics with TWHM2003)
HBT,  InGaP,  GaAs,  ledge,  capacitor,  base resistance,  recombination,  

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InGaP/GaAs HBT with novel ledge coupled capacitor (LCC) structure has been proposed and demonstrated for the first time. The LCC employs an extrinsic InGaP ledge layer as a capacitor parallel to the base resistor. This configuration enables feeding RF signals directly into the base without passing them through the base resistor. With the fabricated HBT, no increase of leakage current between emitter and base electrode was observed. The maximum oscillation frequency (fmax) of the HBT was improved by 10 GHz as compared with an HBT without the LCC.