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Use of Ion Damage to Reduce the Amount of As Precipitation in High C(o) Diffusions

IP.com Disclosure Number: IPCOM000074745D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Crowder, BL: AUTHOR [+2]

Abstract

A two step process is used in fabricating emitters in bipolar transistors. Very high electrically active arsenic concentrations are obtained.

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Use of Ion Damage to Reduce the Amount of As Precipitation in High C(o) Diffusions

A two step process is used in fabricating emitters in bipolar transistors. Very high electrically active arsenic concentrations are obtained.

A conventional arsenic diffusion onto a Si substrate is carried out. An amorphous surface layer is produced by bombardment with energetic Si ions. The amorphous region is then recrystallized on the Si substrate at a low temperature, e.g., 600 degrees C, for about 30 minutes. An epitaxial regrowth occurs which results in the incorporation of the As on substitutional sites and in removing any compensating defects produced by ion damage.

A restriction on the location of the boundary between the amorphous region produced by ion implantation and the adjacent heavily-damaged but crystalline region does exist. If this boundary is at or near an active junction, the defects in the heavily-damaged crystalline region, which are not removed by low- temperature annealing, will adversely affect junction characteristics. This restriction, for example, precludes the use of simply ion-implanting the As in conjunction with a low-temperature anneal to achieve a low-nonsubstitutional level. In this case, the interface between the amorphous-crystalline region lies very close to the region where one would like the emitter-base junction. Thus damage by an "inert" species (preferably Si) must be used so that the location of the amorphous-crystalline boundary is suff...