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

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, P_b0 and P_b1 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].