Papers by Keyword: Si-SiO₂ Interface

Abstract: This paper presents the results of the investigation of stress relaxation at the Si-SiO₂ interface using electron paramagnetic resonance (EPR) spectra, scanning electron microscopy (SEM) image technique, deflection analysis, X-ray photoelectron spectroscopy (XPS) and C-V characterisation of metal oxide semiconductor (MOS) structures. It has been shown, on the basis of EPR, XPS, C-V, and deflection data, that the mechanism of stress relaxation depends on the oxidation conditions: temperature, cooling rate and oxide thickness. In the Si-SiO₂-Si₃N₄ system the stress relaxation occurs due to the difference in the thermal expansion coefficient of SiO₂ and Si₃N₄ material. With an appropriate choice of oxidation conditions compressive stresses in SiO₂ and tensile stresses in Si are almost equal and stress can be reduced considerably at the interface.

Abstract: The effect of ultrasonic treatment (UST) on the defect structure of the Si–SiO₂ system is characterised by means of electron spin resonance (ESR), metallography, MOS capacitance measurements and secondary ion mass spectroscopy (SIMS). A non-monotonous dependence of the defect densities on the ultrasonic wave intensity has been observed. The influence of the UST frequency on the ESR signal intensity of the defect centres depended on the defect’s type and structure and may be caused by vibrational energy dissipation which is a function of the defect centre’s type. The influence of the UST on the Si–SiO₂ interface properties depends on the oxide thickness and crystallographic orientation. The density of point defects and absorbed impurities at the Si–SiO₂ interface can be reduced and its electrical parameters improved by an appropriate choice of UST and oxidation conditions.

Abstract: The results of an investigation of the point defects (PD) generation, redistribution and interaction with impurities in the Si-SiO₂ system during the process of its formation in use of of electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectra are presented. The type and density of the point defects that are generated in the Si surface layer during thermal oxidation depend on the oxidation conditions: temperature, cooling rate, oxidation time and impurity content. The difference between interface properties of n- and p-type wafers could be related to different Fermi level position at the interface and to different PD densities in volume.

Abstract: It has been shown by means of EPR and NMR technique that at the Si-SiO2 interface at appropriate oxidation temperature (time) local dynamical equilibrium may be achieved. At oxidation temperature 1130oC the dencity of point defects is less than at lower and higher temperature (1100oC and 1200°C) and the content of absorbed impurities (hydrogen, oxygen) diminishes.

Abstract: The results of investigation of the point defect generation and interaction with impurities in the Si-SiO2 system during the process of its formation by means of electron paramagnetic resonance (EPR) and nucleous magnetic resonance (NMR) technique are presented. It has been shown that the diference in point defects interaction with hydrogen at the Si-SO2 interface with n- and p-type conductivity are connected with the sign of hydrogen ions incorporation dependence on the Fermi level position in accordance with the proposed model. The interface properties may be improved by laser irradiation.

Abstract: The type and density of the point defects that are generated in the Si surface layer during thermal oxidation depend on the oxidation condition: temperature, cooling rate, oxidation time, impurity content. Interaction between the point defects with extended defects and impurities affects the SiO2 structure and Si-SiO2 interface properties. Hydrogen adsorption on n- and p- type wafers is different. One possible reason for that can be the strength of the magnetic interaction between the hydrogen and paramagnetic impurities of the adsorbent. The influence of point defects and impurities may be diminished and the interface properties improved by an appropriate choice of the oxidation conditions and postoxidation laser irradiation.