Ranges and Distributions of Ions Implanted in Dielectrics

Abstract

The projected range and range straggling of Zn, Ga, As, Se, Ce, and Te implanted in SiO₂, Si₃N₃, and Al₂O₃ at energies between 150 and 300₊keV were measured by backscattering techniques with 2.0 MeV He ions. The range distributions were measured relative to the thickness of the dielectric films by an analytical method which is insensitive to errors in the stopping power of He ions in dielectrics. The projected ranges, p_p in LSS normalized units, as a function of LSS normalized energy, ε, followed the relationship p=2.7ε where the arithmetic average atomic number of the target M₂=20, average atomic number Z₂=20 and average mass number Z₂=20 were used for all three dielectrics. The projected range values were systematically greater than LSS calculations by ratios of 1.2 to 1.5. Heat treatment of 900°C after implantation produced a movement of Zn, Ga, and Cd in SiO₂ toward the surface. This motion was shown to be associated with radiation damage in SiO₂. No motion was detected for other species in SiO₂, nor for any of the implanted species in Si₃N₄ and A1₂0₃ for anneal temperatures up to 1000°C for 30 minutes.

Work supported in part by Air Force Cambridge Research Laboratories.