Self-ordered microcavities embedded in ultrashallow silicon p-n junctions

Abstract

Scanning tunneling spectroscopy was used to obtain topographic images of the (100) surface of ultrashallow diffusion profiles of boron in silicon. This method makes it possible to study the influence of fluctuations of the surface deformation potential, which depend on the thickness of the preliminary deposited oxide layer and on the crystallographic orientation of the fluxes of nonequilibrium vacancies and self-interstitials that stimulate the exchange mechanisms of impurity diffusion. The existence of self-assembled systems of quantum anti-dots, which are formed due to fluctuations in the surface deformation potential and which are microdefects that penetrate through the diffusion profile of the dopant, is demonstrated for the first time. It is established that a spread in the sizes of quantum anti-dots is reduced with increasing temperature of the impurity diffusion. In addition, the sizes of quantum anti-dots are found to be interrelated to their spatial distribution, which is indicative of a fractal mechanism of formation of self-assembled zero-dimensional systems under conditions of strong interaction of the flux of impurity atoms with that of primary defects. Self-assembled quantum anti-dots embedded into a system of silicon quantum wells make it possible to design microcavities with distributed negative feedback; the existence of such microcavities is confirmed by spectral dependences of the reflection and transmission coefficients in the visible and infrared regions of the spectrum, respectively.