Browse Prior Art Database

Transistors With Low Topography

IP.com Disclosure Number: IPCOM000039324D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Chen, TC: AUTHOR [+4]

Abstract

Bipolar transistors can be constructed with lower topographical features by using an n+ - polysilicon contact to the emitter, a self- aligned lateral line and extrinsic base profile, and a self-aligned, planar platinum-silicide contact to the extrinsic base. The sheet resistance of the platinum-silicide is comparable to that of tungsten on silicon. Three alternative emitter and base configurations are shown in Figs. 1-3 in decreasing heights. In construction, an insulation layer 1, such as oxide, passivates the surface of silicon 2. Emitter and (Image Omitted) base contact holes 3 and 4, respectively, are formed at least one overlay tolerance away from the edge of n+ - polysilicon layer 5 and optional tungsten layer 6. A platinum-silicide layer 7 is formed over extrinsic base 4.

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Transistors With Low Topography

Bipolar transistors can be constructed with lower topographical features by using an n+ - polysilicon contact to the emitter, a self- aligned lateral line and extrinsic base profile, and a self-aligned, planar platinum-silicide contact to the extrinsic base. The sheet resistance of the platinum-silicide is comparable to that of tungsten on silicon. Three alternative emitter and base configurations are shown in Figs. 1-3 in decreasing heights. In construction, an insulation layer 1, such as oxide, passivates the surface of silicon 2. Emitter and

(Image Omitted)

base contact holes 3 and 4, respectively, are formed at least one overlay tolerance away from the edge of n+ - polysilicon layer 5 and optional tungsten layer 6. A platinum-silicide layer 7 is formed over extrinsic base 4. Sidewall oxide 8 may be added as shown in Figs. 1 and 2. Thereafter, titanium-tungsten layers 9 and metallization 10 are added. The collector area depends on metallization pitch, as seen in Figs. 2 and 3.

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