Self-Aligned SiGe HBTs with Doping Level Inversion Using Selective Epitaxy

Shuji ITO  Toshiyuki NAKAMURA  Hiroshi HOGA  Satoshi NISHIKAWA  Hirokazu FUJIMAKI  Yumiko HIJIKATA  Yoshihisa OKITA  

IEICE TRANSACTIONS on Electronics   Vol.E82-C    No.3    pp.526-530
Publication Date: 1999/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Ultra-High-Speed IC and LSI Technology)
Category: Silicon Devices
bipolar transistor,  SiGe HBT,  doping level inversion,  cutoff frequency,  selective epitaxy,  

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SiGe HBTs with doping level inversion, that is, a higher dopant concentration in the base than in the emitter, are realized based on the double-polysilicon self-aligned transistor scheme by means of selective epitaxy performed in a production CVD reactor. The effects of the Ge profile in the base on the transistor performance are explored. The fabricated HBT with a 12-27% graded Ge profile demonstrates a maximum cutoff frequency of 88 GHz, a maximum oscillation frequency of 65 GHz, and an ECL gate delay time of 13.8 ps.