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Browse Prior Art Database

Extracting Aluminum from Silicon after Ion Implantation

IP.com Disclosure Number: IPCOM000051395D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+2]

Abstract

Aluminum unintentionally implanted into silicon during the ion implantation of doping material is extracted by low-temperature dry oxidation prior to annealing.

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This is the abbreviated version, containing approximately 100% of the total text.

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Extracting Aluminum from Silicon after Ion Implantation

Aluminum unintentionally implanted into silicon during the ion implantation of doping material is extracted by low-temperature dry oxidation prior to annealing.

Sputtering caused by the ion beam hitting parts of the implanter produces particles, consisting mostly of aluminum, impinging on the silicon surface exposed to ion implantation. Generally, such particles having a lower energy than the doping ions are caught in a screen oxide covering the silicon surface. If the screen oxide is inadequate, the particles are also implanted into the silicon surface.

In a typical arsenic implantation step at an energy of 50 keV, the aluminum is implanted down to a maximum depth of 13 nm. To remove this aluminum, the silicon wafers are dry-oxidized for about 10 minutes at about 800 degrees C, leading to the growth of a 6 nm thick oxide layer. Subsequently, the silicon wafers are annealed at about 1000 degrees C in an iner atmosphere. After annealing, the oxide layer is removed with buffered HF.

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