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Poor mechanical and thermal properties are the chief problems in implementing mesoporous low-κ materials in future integrated circuits. Much work has been done on measuring these physical properties of some candidate low-κ materials; however, there exists no work in the literature tying the internal matrix properties of mesoporous dielectrics to their bulk mechanical properties. Mesoporous silica films were deposited by us over a wide range of porosities, pore size distribution, structure, interconnectivity and chemistry using a binary solvent sol–gel process and by sintering. A detailed pore size and structure characterization was done by using ellipsometric porosimetry (EP) followed by the measurement of the elastic modulus of these films. Both films consisted of mainly two types of pore geometries which were tied to the size of the pores. Sintered films show a narrower pore size distribution with an increased population of micropores in comparison with as-deposited films. We have correlated the elastic properties to the internal matrix structure of the silica pore network and shown that they depend strongly on the film porosity and the pore size distribution in the film. We propose that sintering helps in improving the mechanical strength by modifying the pore size distribution to incorporate a higher fraction of cylindrical micropores in the film. The contribution of the internal solid matrix was minimal as it was found to be perfect in our as-deposited films and our sintering conditions did not modify the backbone structure significantly. Lastly, finite-element simulations for two different pore geometries are shown and support the argument that cylindrical pores show much better mechanical properties than tubular pores for the same porosity.

The paper is devoted to examination of porous silicon properties and structures obtained by molecular beam epitaxy (MBE) methods by methods of ellipsometric porosity measurement. These methods allow one to gain general porosity allocation of pores on the sizes, and also to explore adsorption and optical properties of a material. Also application of an ellipsometric porosity measuring method is described to encapsulating epifilm quality control.

At present, multilayer heteroepitaxial compositions with latent layers of porous silicon are prospective semiconductor structures. This is caused by the opportunity of their use to damp pliable substrates for making multilayer structures with methods of molecular-beam epitaxy (MBE), and for creating radiating p-n transitions. The present paper is devoted to an examination of properties of this material and structures obtained with MBE methods with the aid of ellipsometric measurement of porosity. These methods allows us to obtain allocation of pores on the sizes together with general porosity, and also to explore the adsorption and optical properties of the material.

Ellipsometric porosimetry (EP) is an effective method for characterization of porosity, pore size distribution (PSD) and specific surface area in porous films deposited on top of any smooth substrate. EP is a new modification of the adsorption porosimetry. In situ ellipsometry is used to determine the amount of adsorptive which adsorbed/condensed in the film. Change in refractive index is used to calculate of the quantity of adsorptive present in the film. Results of the analysis are in good agreement with data obtained by other instrumentation like low-temperature nitrogen porosimetry (BJH), positronium annihilation lifetime spectroscopy (PALS) and small angle neutron scattering (SANS).

Porosity and pore size of siloxane-based porous spin-on-glass (SOG) thin films are comparatively studied with different non-destructive methods and also with reference to nitrogen porosimetry. The pore size and its spread are found to increase with increasing porosity, or with decreasing dielectric constant.

Ellipsometric porosimetry (EP) is a simple and effective method for the characterization of the porosity (volume of both open and close pores), average pore size, specific surface area and pore size distribution (PSD) in thin porous films deposited on top of any smooth solid substrat e. Because a laser probe is used, small surface area can be analyzed. Therefore, EP can be used on patterned wafers and it is compatible with microelectronic technology. This method is a new version of adsorption (BET) porosimetry. In situ ellipsometry is used to determine the amount of adsorptive which adsorbed/condensed in the film. Change in refractive index is used to calculate of the quantity of adsorptive present in the film. EP also allows the study of thermal stability, adsorption and swelling properties of low-K dielectric films. Room temperature EP based on the adsorption of vapor of some suitable organic solvents and method of calculation of porosity and PSD is discussed. Examination of the validity of Gurvitsch rule for various organic adsorptives (toluene, heptane, carbon tetrachloride and isopropyl alcohol) has been carried out to assess the reliability of measurements of pore size distribution by the ellipsometric porosimetry.

The optical properties and electrical conductivity of pyrolytically formed oxynitride films were investigated. Experimental work on the electron photoemission from aluminium and silicon made it possible to determine the electron affinity for silicon oxynitride films with a varying oxygen and nitrogen content. The band gaps for oxynitride films with a composition close to silicon nitride were determined from the spectral dependence of the absorption coefficient for photon energies exceeding the band gap. A band diagram for silicon oxynitride with a varying oxygen and nitrogen content was constructed on the basis of the findings. The electrical conductance of the films varies gradually over a range of six orders of magnitude from SiO 2 to Si 3 N 4 . The conductivity of films with a composition close to that of silicon nitride is governed by the Frenkel mechanism; for compositions nearer to SiO 2 there is a change to a contact-limited conduction mechanism. In films with a composition close to Si 3 N 4 both the electron current and the hole current contribute to the conductivity.