Persons

Plasma-enhanced CVD silicon nitride films SiN obtained from the gases of SiH and NH are widely used in microelectronics, micro- and nanoelectromechanical systems. For many applications, the residual mechanical stresses and composition of films are important characteristics. The properties of SiN films (in particular mechanical stresses and composition) significantly depend on deposition conditions: the reacting gases ratio, gas mixture composition, power and frequency of plasma generator, temperature and pressure at deposition. Despite the large amount of research, the obtained data on dependence of the properties and composition of SiN films on the deposition conditions are not sufficiently complete. In the present work, the influence of the reacting gases ratio on the mechanical stresses and composition has been studied for the PECVD silicon nitride films SiN , obtained from a gaseous mixture of SiH and NH using a low-frequency plasma. It was found that for PECVD SiN films with increasing of the reacting gases ratio (SiH to NH) from 0,016 to 0,25 the compressive mechanical stress decreases by 31%, the stoichiometric coefficient decreases from 1,40 to 1,20, the refractive index increases from 1,91 to 2,08, the concentration of N-H bonds decreases 7,4 times, the concentration of Si-H bonds increases 8,7 times and the concentration of hydrogen atoms decreases by 1,5 times. The obtained dependences can be used for controlled production of SiN films with specified characteristics: residual mechanical stresses, refractive index, stoichiometric coefficient and concentration of hydrogen-containing bonds.

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The simulation of the primary gas flow rate converter of membrane type based on the operation calorimetric principle has been carried out. Several options of the sensor construction have been considered. The results of numerical modeling for different variants of the sensor design in terms of the maximum sensitivity have been analyzed. The results permit to find the optimal for the moment the thermal sensor configuration and location.

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An algorithm of the relief analysis for the purpose of calculating the mechanical stresses in selected direction on a wafer in the form of a program package Matlab has been designed and implemented. The method provides the possibility of measurement at each point of the sample that delivers a visual picture of the data to obtain the distribution of mechanical stresses on the wafer surface. Using this technique the measurement of mechanical stresses in the film of plasma chemical silicon nitride has been conducted. The analysis in the environment of the device-technological simulation TCAD has been performed.

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