Paper SS2-FrM10
Defect Engineering via Modification of Semiconductor-Oxide Interfaces

Friday, November 13, 2009, 11:20 am, Room N

The behavior of defects within silicon can be changed significantly by controlling the chemical state at nearby surfaces or solid interfaces. Experiments have shown that certain chemical treatments change the ability of a free surface to act as a “sink” for point defects such as interstitials. When the surface is made chemically active, this ability rises. The surface can then remove Si interstitials selectively over impurity interstitials and such behavior can be kinetically quantified through an annihilation probability. Although annihilation probabilities for interstitials have been measured under various conditions for free surfaces, very little understanding exists for the corresponding quantity at solid-solid interfaces. Understanding of interface influence on interstitial annihilation is very important in fabrication of advanced transistors for post-implantation damage removal and dopant activation. The present work seeks to develop scientific understanding of interface activity for Si interstitial annihilation and measure the annihilation probabilities at interfaces between silicon and several kinds of oxides and nitrides. Diffusion of isotopically labeled Si (mass 30) in Si host lattice was used as a marker for elucidating how changes in the Si-SiO₂ interface affected Si self-diffusion after annealing. Marked differences are observed among the various interfaces. Continuum simulations of the measured SIMS profiles were subsequently employed to quantify annihilation rates at the Si-SiO₂ interface.