Thermal Oxidation of Porous Silicon: Study on Reaction Kinetics

Autor:	Seppo Leppävuori, Andrea Edit Pap, Krisztian Kordas, Thomas F. George
Rok vydání:	2004
Předmět:	Arrhenius equation Thermal oxidation Chemistry Analytical chemistry Activation energy Atmospheric temperature range Chemical reaction Surfaces Coatings and Films Reaction rate Chemical kinetics symbols.namesake Reaction rate constant Materials Chemistry symbols Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry B. 108:12744-12747
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp049323y
Popis:	Porous silicon (PS) samples obtained by dark etching of p+-type silicon wafers are oxidized in dry air, at various temperatures from 200 °C up to 800 °C for 1−20 h durations, to determine the kinetics of the reaction. The extent of oxidation calculated from mass gains is plotted as a function of oxidation time and temperature. By fitting the general reaction kinetic solutions of different-order reactions, one finds that the function valid for first-order kinetics gives the best matches. From the obtained reaction rates, the pre-exponential factors and activation energies of the oxidation process are determined using Arrhenius plots. It is found that, depending on the temperature range of the oxidation process, either one or two chemical reactions take place. At lower temperatures (200−400 °C), a reaction with an activation energy Ea,1 ≈ 7 kJ·mol-1 and a pre-exponential factor A1 ≈ 0.2 h-1 dominates. When the temperature is increased (400−800 °C), a second reaction starts, showing Ea,2 ≈ 50 kJ·mol-1 and A2...
Databáze:	OpenAIRE
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