Browse Prior Art Database

Complementary Bipolar Technology With Optional Implanted or Low Temperature Epitaxy Base

IP.com Disclosure Number: IPCOM000122698D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 102K

Publishing Venue

IBM

Related People

Burghartz, JN: AUTHOR [+4]

Abstract

Described is a fabrication process that features the integration of independent NPN and PNP transistor devices into the same technological flow. Produced is an implanted-base PNP device with a low temperature epitaxy (LTE) base NPN transistor.

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Complementary Bipolar Technology With Optional Implanted or Low Temperature
Epitaxy Base

      Described is a fabrication process that features the
integration of independent NPN and PNP transistor devices into the
same technological flow.  Produced is an implanted-base PNP device
with a low temperature epitaxy (LTE) base NPN transistor.

      The technological process of conventional NPN and PNP
transistors assumes that a complementary structure should meet the
following criteria:
       Since arsenic has a very low diffusion coefficient and boron a
very high diffusion coefficient, the As doped base of the PNP device
should be fabricated before the processing of the B doped base of the
NPN transistor is started.
     - The NPN device should be finished before the P-emitter is
formed because the boron emitter of the PNP tends to diffuse out
rapidly.

      Based on the above criteria, the complementary technology
process is defined as follows:
     1) After finishing the sub-collector process, both collector re
gions are implanted and defined with two masks.  A nitride/oxide
stack is formed to define the emitter region of the PNP.  The same
material protects the NPN and the collector contacts.  A spacer is
formed on the nitride/oxide stack in order to space the subsequent
extrinsic base implant a controlled distance from the emitter
opening.  After stripping the spacer and adding an additional link
implant (if desired), a local oxidation is carried out to passivate
the surface of the PNP extrinsic base, as shown in Fig. 1....