Analytical model for oblique ion reflection at the Si surface

Experimental and analytical studies on oblique ion implantation into a Si trench sidewall are discussed. The observation that implanted ions at small incident angle are reflected at the trench sidewall cannot be explained by the conventional Gaussian distribution model. A simple analytical model for oblique ion reflection, considering the Rutherford scattering collision between implanted ions and the Si nucleus, is introduced. As the ion incident angle becomes smaller than 10°, more and more ions are reflected at the trench sidewall. In addition, the reflection index of arsenic ions is larger than that of phosphorus ions