Critical problems of ion implantation in processing small geometry integrated devices

A brief review is described on the critical problems of ion implantation in processing small geometry integrated devices. The commonly recognized critical paths of the technology, i.e. formation of shallow junctions, impurity doping of vertical side walls, shadowing and the scattering effect of the incident beam are discussed based on recent data. Discussion is also given of the annealing behavior and residual defects of small and isolated implanted regions, and the considerable difference from those of the continuous implanted layers is shown. These problems are more or less related to the fundamental principles of implantation that impurities are doped by the incidence of energetic ions. Based on these facts, attempts are made to estimate the final size of the future devices to which implantation can be applied.