NEW APPROACH TO GROW PSEUDOMORPHIC STRUCTURES OVER THE CRITICAL THICKNESS

We propose to grow pseudomorphic and heteroepitaxial structures on thin, free-standing substrates. From the theoretical analysis, pseudomorphic layers of arbitrary thickness can be grown on a substrate thinner than the critical thickness. Even if the substrate is twice as thick as the critical thickness, very high-quality heteroepitaxy can still be achieved with all the threading dislocations gettered by the thin substrate. The conclusions derived from the theoretical models can be applied to most of the pseudomorphic and heteroepitaxial material systems of current interest.