Electron Spin Resonance Observation of Bias-Temperature Stress-Induced Interface Defects at NO/N₂O-Annealed Chemical-Vapor-Deposition SiO₂/(100) p-Si Substrates

Abstract

Using an electron spin resonance (ESR) technique, we observed bias-temperature (BT) stress-induced interface defects at chemical-vapor-deposition (CVD) SiO2/(100) p-Si substrates annealed in either NO or N2O gas. The g-factors and peak widths detected by ESR measurements are 2.0058 and 0.35 mT, and 2.0035 and 0.40 mT for interface defects, Pb0 and Pb1 centers, respectively. Before BT stress application, the total density of ESR-active defects at the interface was determined to be 1.51×1012 cm-2 for the NO-annealed sample, which is supposed to include a large number of hydrogen (H) atoms near the interface, and 1.85×1012 cm-2 for the N2O-annealed sample, which is supposed to include a small amount of H atoms. After BT stress application, the total interface defect density increases with positive BT stress time monotonically, which is mainly caused by H desorption reaction. In contrast, in the case of negative BT stress application, the total density decreases first, and then increases, which might be caused by two reactions; the first reaction is [·Si\tbondSi3→Si\tbondSi3], and the second reaction is [HSi\tbondSi3→H·Si\tbondSi3→·Si\tbondSi3].