Ion-implantation distributions in non- uniform targets: Projected range

Abstract

Ion-implantation range distributions in inhomogeneous media are calculated with angular deflections included in the P ₁ approximation. The calculations assume power cross sections and neglect electronic stopping. The natural length scale found earlier in the path-length approximation is shown to be general. Attention is concentrated on a two-medium target, but the method may be generalized in an obvious manner to any number of layers of different target media. Results are more explicit when the source and the interface coincide, and are examined in greater detail when the medium behind the coincident source and interface is the vacuum. In this case the mean range within a semi-infinite medium and the reflection coefficient are calculated. The results are expected to be valid for slow light ions on a heavy-atom target. The reflection coefficient is in good agreement with earlier calculations when the target-atom/projectile mass ratio is large.