The Lattice Misfit and Its Compensation in the Si‐Epitaxial Layer by Doping with Germanium and Carbon

Abstract

When germanium and carbon are doped into silicon, the silicon lattice is expanded or contracted depending on the tetrahedral covalent radius of germanium or carbon, respectively. But this effect of electrically nonactive elements can be of considerable use for compensating the lattice strain caused by other impurities, which are electrically active elements in silicon. From the investigation of the electrical characteristics and lattice defects of epitaxial layers doped with germanium, it was found that doping of germanium in silicon up to does not change the electrical characteristics of silicon and also that germanium is an element suitable for strain compensation in silicon. By the single doping of carbon over its solubility, many defects were generated. However, when carbon and antimony are simultaneously doped into the epitaxial layers, the layers become free from lattice defects and the saturation solubility of carbon in silicon changes from a solubility concentration of to with an increase in the concentration of antimony. These results show that the saturation solubility of carbon depends largely on the lattice strain or the existence of an impurity.