Optical and Compositional Properties of SiOx Films Deposited by HFCVD: Effect of the Hydrogen Flow

López, José Alberto Luna; Valerdi, D. E. Vázquez; Lara, Alfredo Benítez; Garcı́a-Salgado, G.; Luz, A. D. Hernández-de la; Morales–Sánchez, A.; Gracia, F.J.; Dominguez, Miguel A.

doi:10.1007/s11664-016-5271-1

Cited by 11 publications

(5 citation statements)

References 38 publications

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“…In recent years, silicon oxide (SiO x ) based coatings (a combination of stoichiometric oxide (SiO 2 ) with a non-stoichiometric sub-oxide (SiO x , x < 2) [1]) have been studied due to their technological importance in numerous applications, including microelectronics [2], communication [3], pharmaceutical, food and packaging industries [4,5]. The use of silicon oxide coatings as a dielectric insulator of electronic switches and sensing devices such as thin-film transistors (TFTs), metal-insulator-semiconductor (MIS) switching devices, optical coatings and optoelectronic applications or even in processes associated with the fabrication of micro-electromechanical-systems (MEMS), serving for example, as etch masks in bulk micromachining or as sacrificial layer in surface micromachining processes [6][7][8][9] is particularly noteworthy due to its properties, as SiO x compounds are known to have good abrasion resistance, electrical insulation, high thermal stability and also being insoluble in the majority of acids.…”

Section: Introductionmentioning

confidence: 99%

Compositional, Optical and Electrical Characteristics of SiOx Thin Films Deposited by Reactive Pulsed DC Magnetron Sputtering

et al. 2019

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The influence of O2 flow rate on the compositional, optical and electrical characteristics of silicon oxide (SiOx) thin films (x < 2) were studied in this work. The SiOx thin films were obtained by pulsed direct current (DC) magnetron sputtering (PMS) onto n-type Si wafers (and also on glass substrates) at a vacuum of 3 × 10−3 Pa. Rutherford backscattering spectrometry (RBS) was used to check the compositional elements of deposited films and its oxidized states were analysed via Fourier-transform infrared (FTIR) spectroscopy. The optical properties of as-deposited SiOx thin films were investigated from transmittance measurements at room temperature in the wavelength range of 250–800 nm. The obtained data reveal that the Urbach energy (a measure of the band tail extension, Eu) decreased from about 523 to 172 meV as the rate of oxygen gas flow increased. On the contrary, the optical energy band-gap (Eg) increased from 3.9 to 4.2 eV. Conduction and valance band positions (relative to the normal hydrogen electrode) were also evaluated. The observed behavior is probably associated with the degree of disorder and defects presented in the as-deposited SiOx thin films, probably due to the presence of newly inserted oxidized OnSiHy species resulting from some contamination with water vapor desorbed from the walls of the deposition vacuum chamber. After deposition of a gold top electrode, the electrical characteristics of the fabricated Au/SiOx/n-Si system (i.e., a metal/insulator/semiconductor structure—MIS) were studied via characteristic I-V curves and their dependence upon the O2 flow rate are reported. It was observed that the Au/SiOx/n-Si structure behaves like a Schottky-diode exhibiting a very good diode rectifying performance with a rectification ratio of at least 300 and up to 104, which refers to the samples produced with the lower and higher O2 flow rates, respectively. It was also found that the O2 flow rate influences the rectifying performance of the SiOx/n-structures since both the diode ideality factor, n, and the diode series-resistance, RS decreases with the increase of O2 content, possibly reflecting a closer approximation to a full stoichiometric condition.

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Section: Introductionmentioning

confidence: 99%

Compositional, Optical and Electrical Characteristics of SiOx Thin Films Deposited by Reactive Pulsed DC Magnetron Sputtering

et al. 2019

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“…The temperature of deposit zone is measured by means of a type-K thermocouple on the substrate. The SRO films typically obtained before of the outlet modification had a thickness ranging from 1 to 8 𝜇𝜇m [17].…”

Section: Methodsmentioning

confidence: 99%

“…Such thicknesses became thinner since they changed from the micrometer range to nanometer one for all flow levels and source-substrates distances. The average film thickness before the modification ranged from 1 µm to 8 µm [17] after the modification it ranged from 122 nm to 593nm. The film thickness calculated has an average value which results from measurements made on different points distributed on all the wafer surface.…”

Section: Profilometry and Sem Micrographymentioning

confidence: 99%

“…In composite materials of silicon rich oxide, SRO, silicon nano-particles (Si-nps) are embedded in a matrix of SiO2, which have been widely studied because of their interesting photoluminescent properties aimed to optoelectronics applications [1,2].The SRO films has been deposited by plasmaenhanced chemical vapor deposition (PECVD) [3], Sputtering [4], Ionic implantation [5] and hot filament chemical vapor deposition (HFCVD) [6]. HFCVD is a technique suitable for obtaining SRO films, this material is obtained by thermal decomposition of the hydrogen gas and a solid source of quartz, from which we obtain the suitable chemical resulting reaction.…”

Section: Introductionmentioning

confidence: 99%

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Computational Simulation of a Hot Filament Chemical Vapor Deposition Process for Depositing SRO Films

Martínez

Luna-López

Sies

et al. 2021

AMR

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In the present report, a two dimensional (2D) model was developed to describe the fluid dynamics, heat and mass transfer of a Chemical Vapor Deposition activated by a Hot Filament (HFCVD) reactor, as well as the chemical generation of the precursor species which are present in the growth of non-stoichiometric silicon rich oxide (SRO) films. The SRO is known for have excellent photo luminescent properties which are useful in optoelectronic applications. This material can be obtained by the HFCVD technique which offers important advantages such as the easily to obtain thin films with diverse structural, compositional and optical characteristics. During deposition is a priority to control key parameters as inlet flow, substrate temperature and pressure so it compels to know previous theoretical information about these parameters which can be obtained by computational simulation. Therefore, by means of commercial Computational Fluid Dynamics (CFD) were solved the continuity, momentum and energy equations in steady state. Also, a thermodynamic equilibrium study of the SiO2(s) + H2 (g) reaction was carried out with the Factsage software. The thermodynamic equilibrium results provide the main chemical species which are present during the deposit process of the SRO films. The 2D model was used to simulate the temperature and velocity distribution of the hydrogen in the deposit process. The theoretical calculated temperatures were compared with those obtained experimentally by thermocouple measurements. From the simulation results, the temperature and gas velocity profiles were obtained at different hydrogen flow levels (50, 75, 100 sccm) and temperature source-substrate distances (5, 6 and 7mm) for a 50 sccm level. SEM micrographs and profilometry measurements disclose that the outlet configuration affects substantially both the thickness and surface uniformity of the SRO films. This parameter was modified to obtain a better quality (thickness and uniformity) and a large deposit area.

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“…Silicon-rich oxide (SRO) is a multiphase material with interesting structural, electrical, and optical properties that can be tuned by silicon excess and defects in thin films [ 1 , 2 , 3 ]. SiO x materials are strongly influenced by oxygen content, as it determines their optical and electrical properties, such as absorption coefficient, band gap energy, luminescence, refractive index, and electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

MIS-Like Structures with Silicon-Rich Oxide Films Obtained by HFCVD: Their Response as Photodetectors

Conde

López

Simón

et al. 2022

Sensors

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MIS-type structures composed of silicon-rich oxide (SRO), thin films deposited by hot filament chemical vapor deposition (HFCVD), show interesting I-V and I-t properties under white light illumination and a response as photodetectors. From electrical measurements, it was found that at a reverse bias of −4 V, the illumination current increased by up to three orders of magnitude relative to the dark current, which was about 82 nA, while the photogenerated current reached a value of 25 μA. The reported MIS structure with SRO as the dielectric layer exhibited a hopping conduction mechanism, and an ohmic conduction mechanism was found with low voltage. I-t measurements confirmed the increased photogenerated current. Furthermore, the MIS structure, characterized by current-wavelength (I-λ) measurements, exhibited a maximum responsivity value at 254 mA/W, specific detectivity (D*) at 2.21 × 1011 cm Hz1/2 W−1, and a noise equivalent power (NEP) of 49 pW at a wavelength of 535 nm. The structure exhibited good switching behavior, with rise and fall times between 120 and 150 ms, respectively. These rise and decay times explain the generation and recombination of charge carriers and the trapping and release of traps, respectively. These results make MIS-type structures useful as photodetectors in the 420 to 590 nm range.

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Optical and Compositional Properties of SiOx Films Deposited by HFCVD: Effect of the Hydrogen Flow

Cited by 11 publications

References 38 publications

Compositional, Optical and Electrical Characteristics of SiOx Thin Films Deposited by Reactive Pulsed DC Magnetron Sputtering

Compositional, Optical and Electrical Characteristics of SiOx Thin Films Deposited by Reactive Pulsed DC Magnetron Sputtering

Computational Simulation of a Hot Filament Chemical Vapor Deposition Process for Depositing SRO Films

MIS-Like Structures with Silicon-Rich Oxide Films Obtained by HFCVD: Their Response as Photodetectors

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