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Shallow Junctions by Dual Implantation and Annealing

IP.com Disclosure Number: IPCOM000062638D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Harrison, HB: AUTHOR [+2]

Abstract

This article relates generally to integrated circuit construction and, more particularly, to the formation of source/drain junctions. Desired but opposing properties of shallow source/drain junctions with high conductivity and low resistivity are achievable through steps of dual implantation and annealing. After normal processing of a semiconductor to the point of source/drain construction, a first set of implantation and annealing steps is undertaken. Implantation dosage is adjusted to avoid, as much as possible, concentration-enhanced diffusion. Conventional dopants, such as arsenic or boron, can be used for the first step, or antimony or gallium may also be used. Specific dosage and energy depend on the species involved. High temperature annealing (900-950ŒC) then takes place.

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Shallow Junctions by Dual Implantation and Annealing

This article relates generally to integrated circuit construction and, more particularly, to the formation of source/drain junctions. Desired but opposing properties of shallow source/drain junctions with high conductivity and low resistivity are achievable through steps of dual implantation and annealing. After normal processing of a semiconductor to the point of source/drain construction, a first set of implantation and annealing steps is undertaken. Implantation dosage is adjusted to avoid, as much as possible, concentration-enhanced diffusion. Conventional dopants, such as arsenic or boron, can be used for the first step, or antimony or gallium may also be used. Specific dosage and energy depend on the species involved. High temperature annealing (900-950OEC) then takes place. The dopant diffuses to a depth sufficient to pass the implant damage layer for a leakage-free junction. This provides a shallow junction, but with unsatisfactory sheet and contact resistivity. The second set of low energy and high dose implantation and annealing steps is then performed to increase dopant concentration. Gallium for p-type or antimony for n-type raises the implanted dopant concentration near the surface. The second annealing is done at approximately 600OEC that regrows the amorphized layer to yield the required dopant concentration. Crystal damage from the second implant is confined to the dopant layer defined by the fi...