Browse Prior Art Database

Improved Base Contact for Collapsor Device

IP.com Disclosure Number: IPCOM000036849D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 86K

Publishing Venue

IBM

Related People

Bartush, TA: AUTHOR

Abstract

A process has been proposed for making a base contact on top of a pedestal in a semiconductor device. The proposal works to make the contact much closer to the actual base region than was done previously thereby lowering base resistance. (Image Omitted)

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Improved Base Contact for Collapsor Device

A process has been proposed for making a base contact on top of a pedestal in a semiconductor device. The proposal works to make the contact much closer to the actual base region than was done previously thereby lowering base resistance.

(Image Omitted)

The conventional pedestal device, or collapsor (Fig. 1) has the configuration shown with the base contact 1, emitter 2 and collector 3 as indicated. This arrangement suffers from a large base volume which results in a high base resistance and it may build up charges due to lateral injection into the base region. The object of this disclosure is to bring the base contact as close to the active region as possible. It would be accomplished using a non-photo, self- aligned technique.

A cross-section of a completed device (Fig. 2) cut through the active region shows the nitride substrate 4, oxide 5, the Si pedestal 6 and metal 7. The pedestal width is 1 mm, as is the width of the two metal regions. In the process sequence for a new base contact, planar quartz 8 (Fig. 3) would be deposited over the foregoing assembly 9. The dimension "h" of the quartz peak 10 is controlled by adjusting the re-sputter rate of the tool, with the low rate being used resulting in high peaks.

(Image Omitted)

A sacrificial layer of photoresist (PR) is applied to planarize and cover the peaks and baked. A reactive ion etch (RIE) is used to etch both the resist and quartz peaks with the etch rate ratio...