Structural and Electrical Characterization of Boron Implanted in Preamorphized Silicon Layers

Low energy boron ions are implanted in silicon substrates, preamorphized by self-ion bombardment. Dopant activation is obtained by conventional furnace heat treatments. The X-ray rocking curves, obtained by (n, –n, n) triple crystal geometry from the annealed samples, are simulated through application of the dynamical theory of diffraction from imperfect crystals. The strain profiles so obtained consist of a surface region of lattice contraction due to substitutional boron and a buried layer of lattice expansion produced by the dislocation loops at the original amorphous—crystalline interface. After conversion from lattice strain to boron concentration, the dopant profiles are obtained and compared with the carrier distributions determined by electrical measurements. This comparison provides information on the nature of the inactive boron.