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Enhanced Uniformity of GaAs FETs by Dual Implant

IP.com Disclosure Number: IPCOM000037769D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hovel, HJ: AUTHOR

Abstract

The nonuniformity of device properties across GaAs processed wafers can be improved by implanting donors jointly from group 4 and group 6 of the Periodic Table. The group 4 impurity resides on the Ga site while the group 6 resides on the As site. This increases the uniformity by eliminating the effect of variations in Ga and As vacancies across wafers; it is these relative vacancy variations that give rise to differences in donor densities and FET properties when only one donor impurity specie is implanted. The invention can be implemented, for example, by co-implanting both Si and Se into GaAs such that the total dose is the same as that used for either impurity alone.

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Enhanced Uniformity of GaAs FETs by Dual Implant

The nonuniformity of device properties across GaAs processed wafers can be improved by implanting donors jointly from group 4 and group 6 of the Periodic Table. The group 4 impurity resides on the Ga site while the group 6 resides on the As site. This increases the uniformity by eliminating the effect of variations in Ga and As vacancies across wafers; it is these relative vacancy variations that give rise to differences in donor densities and FET properties when only one donor impurity specie is implanted. The invention can be implemented, for example, by co-implanting both Si and Se into GaAs such that the total dose is the same as that used for either impurity alone. The same threshold voltage and other FET properties are then obtained as would be obtained with either alone except that the uniformity is enhanced through elimination of the effect of variable vacancy distributions, and therefore elimination of the effect of dislocations.

The technique would work equally well for other III-V compounds and other group 4/group 6 species. Different doses and implant energies can also be used if desired for the two species.

Disclosed anonymously.

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