Local Epitaxy under Conditions of Strong Growth Rate Anisotropy

The possibility of using protective silicon dioxide masks for the localization of growth in the epitaxial deposition of semiconductor materials was established at the beginning of the 60’s [1, 2], Many publications have been devoted since then to the study and development of planar selective epitaxy, a process in which the holes etched through windows in the protective mask are filled in a controlled manner by the epitaxially deposited material. Practical cases of great interest are planar local epitaxial structures in which the surface of the grown layer coincides (is coplanar) with the surface of the original substrate. It has been shown [3–7] that considerable difficulties have to be overcome to achieve coplanarity in the desired structures. The holes may be filled both by upward growth from the bottom (normal growth) and via growth starting from the side walls of the holes (tangential growth); consequently, a specific ratio of the normal and tangential growth rates must be maintained to achieve coplanarity.