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Complementary SiGe Heterojunction Bipolar Transistor Process with Common Sige Epilayer

IP.com Disclosure Number: IPCOM000110058D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 3 page(s) / 96K

Publishing Venue

IBM

Related People

Comfort, JH: AUTHOR [+2]

Abstract

A process is described whereby a single epitaxial SiGe layer is used to fabricate both a PNP and an NPN Heterojunction Bipolar Transistor (HBT) in an integrated, complementary fashion. Both structures resemble the industry standard double-poly transistor structure but may have either ion-implanted or epitaxial bases (either UHV/CVD or selective SiGe deposition) as desired.

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Complementary SiGe Heterojunction Bipolar Transistor Process with Common Sige Epilayer

       A process is described whereby a single epitaxial SiGe
layer is used to fabricate both a PNP and an NPN Heterojunction
Bipolar Transistor (HBT) in an integrated, complementary fashion.
Both structures resemble the industry standard double-poly transistor
structure but may have either ion-implanted or epitaxial bases
(either UHV/CVD or selective SiGe deposition) as desired.

      It is difficult to fabricate complementary heterojunction
bipolar transistors using in-situ doped SiGe epitaxial layers since
this requires two different SiGe depositions occuring at widely
different points in the fabrication sequence.  The primary
difficulties are related to  controlling the thermal budget to
achieve intrinsic base width control in each structure, protecting
each device during processing of the other and removal of undesired
SiGe deposits formed during the second epitaxial deposition.  An
integrated process is proposed in which a single, intrinsic SiGe
epitaxial layer is deposited and patterned for use in both a PNP and
an NPN double-poly bipolar transistor.  This process provides two
devices with identical structures and topography and which both
utilize a SiGe base region.  Dopant introduction into the SiGe base
regions is then accomplished using either ion-implant techniques or
using low temperature epitaxial deposition to provide a dopant
diffusion source above the base...