Experimental and theoretical investigation of formation of the oxygen-containing precipitate-dislocation loop system in silicon

A model of coherent and incoherent oxygen-containing precipitates formed in an anisotropic silicon crystal due to the decomposition of a supersaturated oxygen solid solution has been considered. The stresses acting inside and outside the precipitate have been determined in the framework of the classical Eshelby’s approach. A criterion has been proposed for the generation of the misfit dislocation and the onset of motion of the perfect interstitial dislocation loop lying in the precipitate plane. The proposed precipitate model and criterion have been used for determining the dependence of the precipitate radius that corresponds to the formation of the misfit dislocation and the onset of motion of the perfect interstitial dislocation loop when an external load is applied to the sample. The results obtained are compared with the available experimental data.     

Determination of the sheet resistance of semiconductor films via near-field microwave microscopy

A method is proposed for determining the sheet resistance of a semiconductor film on a dielectric substrate with the help of a near-field (NF) microwave microscope. The method is based on the theory of NF probing of the object with an arbitrary 1D permittivity profile. The theoretical model parameters are found from calibration measurements performed with the use of a universal set of reference samples. The test structures are GaN films grown on an Al₂O₃ substrate. A comparison with dc measurements indicates that the method error is approximately 20%.     

Interamination of some aminooxypyrimidines

Bis(pyrimidinyl)amines have been prepared by reaction of aminooxypyrimidines with aminooxypyrimidine hydrochlorides.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 169–173, January, 1992.     

Synthesis of 1-Methyl and 1-Benzyl 3,5-Bis(ω-Mercaptoalkyl) Isocyanurates

1-Methyl and 1-benzyl 3,5-bis(-haloalkyl) isocyanurates were reacted with thiourea to obtain 1-methyl and 1-benzyl 3,5-bis[-[amino(imino)methylmercapto]alkyl] isocyanurates, respectively. Hydrolysis of the latter gave the corresponding 3,5-bis(-mercaproalkyl) izocyanurates.     

Synthesis of α,ω-Bis(3-methyl- or 3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydro-1-pyrimidinyl)alkanes

The reactions of stoichiometric amounts of sodium salts of 2-hydroxy-3-methyl-4-oxo-3,4-dihydropyrimidine or 2-hydroxy-3,6-dimethyl-4-oxo-3,4-dihydropyrimidine and dibromoalkanes in dimethylformamide were used to synthesize ,-bis(3-methyl- or 3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydro-1-pyirimidinyl)alkanes with 1 and 3-5 methylene units in the hydrocarbon brigde.     

The reaction of sodium salts of uracils with chlorides of acids of phosphorus. I

The reaction of the sodium salts of 6-methyluracil (I) and 3, 6-di-methyluracil (II) with methyl and ethyl phosphorochloridates and phosphorochloridothioates give the corresponding N-methyl and N-ethyluracils. The reaction of I with dimethyl phosphorochloridothioate has given a phosphorus- containing reaction product the structure of which has not been established.