Enhanced Uniformity of GaAs FETs by Dual Implant
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-29
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.