Browse Prior Art Database

Epi-Based Bipolar Transistor With Oxide-defined Collector Window

IP.com Disclosure Number: IPCOM000120887D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Wu, BS: AUTHOR

Abstract

Disclosed is an epi-based bipolar structure with an oxide-defined collector window smaller than the emitter window.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 69% of the total text.

Epi-Based Bipolar Transistor With Oxide-defined Collector Window

      Disclosed is an epi-based bipolar structure with an
oxide-defined collector window smaller than the emitter window.

      The extrinsic base/collector capacitance and the collector
resistance play an important role in determining the performance of
bipolar transistors and circuits.  By utilizing a "buried oxide" to
define the collector window to be smaller than the emitter window
(Fig. 1), the bipolar structure disclosed virtually reduces the
extrinsic base/ collector capacitance to zero.  In addition, it
excludes the possibility of extrinsic base/collector breakdown and
thus allows a thinner collector epi layer to be used to reduce the
collector resistance.  As a result, this structure improves the
performance of bipolar transistors and circuits.  Since the collector
window is defined by oxide, collector implantation (if used) is
self-aligned and straightforward (no extra mask).

      The structure disclosed here is compatible with conventional
double-poly or single-poly bipolar processes. Listed below is a
modified single-poly process that realizes the bipolar structure
disclosed.
      1.  Start with p- Si substrate.
      2.  Pattern or blanket As doped n+ subcollector.
      3.  Grow 0.2 - 0.3 mm n-epi.
      4.  Shallow trench and optional deep trench process.
      5.  Blanket implant collector and deposit
          oxide/nitride.
     ...