First-principles study of dopant trap level and concentration in Si(110)/a-SiO2 interface

We investigate the dopant trap level and equilibrium concentration of Si(110)/a-SiO
2
2 interface with a wide variety of dopants (B, C, N, Br, Cl, F and H). The electronic and atomic properties of intrinsic and extrinsic defects are analyzed using First-principles calculation. It is shown that the average trap levels for hole and electron deepen as the electronegativity of the dopant increases. Also, we applied a simple thermodynamic model to evaluate the equilibrium concentration of active trap as a function of dopant concentration at the interface. From the model it turns out that H and F completely passivate the intrinsic Pb center of Si and reduce the trap concentration, while other elements, especially N, Br and Cl, induces new trap states which amounts to several times more than the pre-existing Pb center.