Mechanism of formation of the response of a hydrogen gas sensor based on a silicon MOS diode
| Autor: | V. M. Kalygina, V. Yu. Gritsyk, V. I. Balyuba, T. A. Davydova, V. I. Gaman |
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| Rok vydání: | 2008 |
| Předmět: |
Materials science
Silicon Hydrogen Passivation Physics::Instrumentation and Detectors Analytical chemistry chemistry.chemical_element Condensed Matter Physics Space charge Capacitance Atomic and Molecular Physics and Optics Computer Science::Other Electronic Optical and Magnetic Materials Condensed Matter::Materials Science Adsorption chemistry Physics::Atomic Physics Polarization (electrochemistry) Diode |
| Zdroj: | Semiconductors. 42:334-338 |
| ISSN: | 1090-6479 1063-7826 |
| Popis: | Experimental data on the dependence of the flat-band voltage and relaxation time for the capacitance of the space-charge region in an MOS diode (Pd-SiO2-n-Si) on the hydrogen concentration in a hydrogen/air gaseous mixture are discussed. It is assumed that variation in the flat-band voltage U fb in an MOS structure with the thickness d = 369 nm subjected to a hydrogen/air gaseous mixture can be accounted for by the formation of dipoles in the Pd-SiO2 gap due to polarization of hydrogen atoms (H a ). An analytical expression describing the dependence of variation in the flat-band voltage ΔU fb on the hydrogen concentration \( n_{H_2 } \) was derived. In MOS structures with d ≤ 4 nm (or MOS diodes), the value of ΔU fb is mainly controlled by passivation of the centers responsible for the presence of the surface acceptor-type centers at the SiO2-n-Si interface by hydrogen atoms. Analytical expressions describing the dependences of ΔU fb and the capacitance relaxation time in the space-charge region on \( n_{H_2 } \) are derived. The values of the density of adsorption centers and the adsorption heat for hydrogen atoms at the Pd-SiO2 and SiO2-n-Si interfaces are found. |
| Databáze: | OpenAIRE |
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