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CNAA / Theses / 2005 / July /

Thin film semiconductor sensor of CO on the base of SnO

Author: Serghei Dmitriev
Degree:doctor of engineering
Speciality: 01.04.10 - Semiconductors physics and engineering
Scientific adviser: Vladimir Brînzari
doctor, associate professor (docent)


The thesis was presented on the 29 July, 2005
Approved by NCAA on the 22 September, 2005


Adobe PDF document0.85 Mb / in romanian


thin film gas sensor (TFGS), nanodimensional film, spray pyrolysis method (SPM), electronchemosorptional model (ECM), surface potential, gas partial pressure, gas sensitivity and selectivity, group electron technology (GET)


Complex investigations, performed in the frame of given scientific work, had been included: development of the model of TFGS on the base of nanodimensional film of semiconducting SnO2, development and optimization of the low-power consuming and compatible with GET technology of deposition of gas sensitive layers with required parameters, design of the low-power consuming TFGS constructions and technology of their manufacturing excluding utilization of noble and rare materials.

There was proposed and experimentally confirmed the electron-chemosorptional model of the functioning of TFGS on the base nanodimensional metal-oxide film. Model takes into account chemosorptional processes on the surface, establishes interconnection between gas sensitivity, film s electrophysical parameters and concentration of the active (CO) gas in atmosphere and allows to forecasting and controlling the gas sensitive characteristics of nanodimensional film already on the stage of its formation.

Technology of SnO2 gas sensitive nanodimensional films deposition was developed on the base of spray pyrolysis method. Modification of the installation for spray pyrolysis has allowed to considerably increasing the surface uniformity and reproducibility of the deposited film s parameters. Correlation between electrophysical and gas sensitive properties of the film with thickness 30-100 nm was established and optimal regimes of the film formation for achievement of maximal gas sensitivity and selectivity were determined for the TFGS manufacturing on their base.

On the base of performed numerical modeling of temperature distribution in a chip of TFGS there were developed and optimized two low-power consuming constructions of TFGS as well as technology routes of its manufacturing by the GET methods. Developed TFGS can be used for detection of CO and a number of explosive gases (methane, propane, hydrogen) as well as for fire detection.

Results obtained in the frame of dissertation research were published in 32 scientific papers, including one patent. Dissertation is written in Russian and contains 133 pages, 70 figures, 6 tables and 177 references.