Oxygen-related defects in low-dose separation-by-implanted oxygen wafers probed by monoenergetic positron beams

The depth distributions of oxygen-related defects in separation-by-implante d oxygen wafers were determined from measurements of Doppler broadening spe ctra of the annihilation radiation. Vacany-oxygen complexes were introduced by implanting 180-keV oxygen at (2-6)x10(17) cm(-2) into Si substrates. Th eir sizes decreased below the subsurface region (<100 nm) because an agglom eration of vacancy-type defects was suppressed by the interaction between v acancies and oxygen atoms. As the dosage was increased, in the region near the projected range of oxygen, atomic rearrangement of vacancy-type defects occurred, and this rearrangement is considered to introduce SiOx (x<less t han>2) that is stable at high annealing temperatures. Oxygen-related defect s were presented in the superficial Si layer even after annealing at 1350 d egreesC. The concentration of such defects was low when the substrate was i mplanted with a dose of 4x10(17) cm(-2). (C) 2001 American Institute of Phy sics.