Si3 N4/SiO2 Multi-Layer Reflecting Stacks for Photonic Switching Applications

1993 ◽  
Vol 298 ◽  
Author(s):  
D.J. Stephens ◽  
S.S. He ◽  
G. Lucovsky ◽  
H. Mikkelsen ◽  
K. Leo
Keyword(s):  
Optical Properties ◽  
Periodic Structures ◽  
Chemical Vapor ◽  
Optical Path Length ◽  
High Energy ◽  
Fused Silica ◽  
Nitride Film ◽  
Photonic Switching ◽  
Model Calculations ◽  
Nitride Layers

AbstractWe have fabricated stacked-structures comprised of i) fused silica substrates, and ii) near-periodic Si3N4/SiO2 bi-layers by low-temperature, 250°C, remote plasmaenhanced chemical-vapor deposition. Comparing the reflectance of these structures with model calculations, we have been able to identify the effects on the reflectance spectra of departures from i) exact periodicity, ii) not having the constituent dielectric layers each posses an ideal optical path length, OPL, exactly equal to λcentral/4, and iii) the intrinsic dispersion in the dielectric functions of the oxide and nitride materials. We have prepared quasi-periodic structures in which the OPL of the higher index Si3N4 layer was > λcentral/4, and in which the OPL of the lower index SiO2 layer was < λcentral/4. This promotes a second strong reflectance band at an energy that is approximately two times that of the primary band. Calculations have shown that the reflectance values in this band, and near a reflectance minimum on the high energy side of the band, are both very sensitive to changes in the optical properties of the nitride film. We present calculations that demonstrate the effects on the reflectance of this band by a temperature-induced modulation of the optical properties of the oxide and nitride layers.

Some optical properties of waveguides made by high energy ion implantation in fused silica

1992 ◽  
Author(s):  
J. Albert ◽  
B. Malo ◽  
D. C. Johnson ◽  
K. O. Hill ◽  
J. L. Brebner ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ion Implantation ◽  
High Energy ◽  
Fused Silica

The Optical Properties of Plasma-Deposited SiO2 and Si3N4 Bragg Reflectors in the Spectral Range from 1.8 to 3.0 eV

1992 ◽  
Vol 281 ◽  
Author(s):  
D. J. Stephens ◽  
S. S. He ◽  
G. Lucovsky ◽  
H. Mkkelsen ◽  
K. Leo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Periodic Structures ◽  
Spectral Response ◽  
Chemical Vapor ◽  
Visible Spectrum ◽  
Bragg Reflectors ◽  
Spectral Bands ◽  
Entire Visible Spectrum ◽  
Optical Behavior ◽  
Constituent Layer

ABSTRACTWe have prepared 19-layer Si3N4:SiO2/…‥Si3N4:SiO2/Si3N4 (HL/HL/…HL/H), Bragg reflectors by remote plasma-enhanced chemical-vapor deposition, and have adjusted the constituent layer thicknesses to generate highly reflecting films over the entire visible spectrum from approximately 1.8 eV (∼690 nm) to 3.0 eV (∼410 nm). Peak values of the reflectance, in spectral bands with half-widths of ∼0.4 to 0.5 eV, are in the range of 96 to 98 %. The spectral response functions of these stacks exhibit departures from the optical behavior as calculated for exactly periodic structures with λ/4 layer thicknesses, and can be accounted for by taking into account: i) dispersion and absorption in the optical properties of the constituent layers; and ii) departures from the idealized and constant layer thicknessses.

A two-step UV curing process for producing high tensile stressed silicon nitride layers

2012 ◽  
Vol 1455 ◽  
Author(s):  
Tobias Fischer ◽  
Lutz Prager ◽  
Joerg Hohage ◽  
Hartmut Ruelke ◽  
Stefan E. Schulz ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Vacuum Ultraviolet ◽  
Chemical Vapor ◽  
Uv Curing ◽  
High Energy ◽  
Increasing Process ◽  
Nitride Layers ◽  
Uv Curing Process ◽  
Curing Procedure ◽  
Stressed Silicon

ABSTRACTThis experimental study presents a comparison of differently tensile stressed silicon nitride (SiN) layers and their response to irradiation in a vacuum ultraviolet (VUV) curing system. Therefore, three types of silicon nitride with initial stress levels of 450 MPa, 700 MPa and 980 MPa were deposited by plasma enhanced chemical vapor deposition (PECVD). In contrast to industrial standard VUV curing with broadband lamps ≥ 220 nm radiation wavelengths, we analyzed the effects of curing with single wavelengths at 172 nm and 222 nm. The samples were characterized by Fourier Transform Infrared Spectroscopy, ellipsometry, and wafer bow measurement. It could be shown that high energy photons are able to dehydrogenize SiN films more than lower energetic photons compared with lower Si-N-Si crosslinking effects. Furthermore, we could show that a dual combined 172 nm and 222 nm VUV curing procedure can produce films with very low hydrogen concentration and high percentage of structural units consisting of Si-N-Si bonds. In conclusion of this study, an up to +900 MPa stress increasing process could be established.

Raman Analysis Of AlxGa1-xN Films

1997 ◽  
Vol 482 ◽  
Author(s):  
Leah Bergman ◽  
Mitra Dutta ◽  
Michael D. Bremser ◽  
Ok-Hyun Nam ◽  
William G. Perry ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Alloy System ◽  
High Energy ◽  
Line Broadening ◽  
Model Calculations ◽  
Raman Analysis ◽  
Thermal Expansion Coefficients ◽  
X Ray Scattering ◽  
The Difference ◽  
Superlattice Line

AbstractRaman analysis of the E2 mode of AlxGal-xN in the composition range 0 ≤ x ≤ 1 is presented. The lineshape was observed to exhibit a significant asymmetry and broadening toward the high energy range. The spatial correlation model is discussed, and is shown to account for the lineshape. The model calculations also indicate the lack of a long-range order in the CVD (chemical vapor deposition) alloys. These results were confirmed by X-ray scattering: the relative intensity of the superlattice line was found to be negligible. The line broadening of the E2 mode was found to exhibit a maximum at a composition x∼0.5 indicative of a random disordered alloy system. The stress state of the alloys was found to be tensile and was attributed to the difference in the thermal expansion coefficients of the SiC substrate and the film.

Composition, oxidation, and optical properties of fluorinated silicon nitride film by inductively coupled plasma enhanced chemical vapor deposition

1999 ◽  
Vol 14 (3) ◽  
pp. 995-1001 ◽  
Author(s):  
Byung-Hyuk Jun ◽  
Joon Sung Lee ◽  
Dae-Weon Kim ◽  
Tae-Hyun Sung ◽  
Byeong-Soo Bae ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Vapor Deposition ◽  
Inductively Coupled Plasma ◽  
Oxidation Mechanism ◽  
Chemical Vapor ◽  
Nitride Film ◽  
Silicon Nitride Film ◽  
Inductively Coupled

Amorphous fluorinated silicon nitride films have been deposited with the variation of NF3 flow rate using SiH4, N2, Ar, and NF3 gases by inductively coupled plasma enhanced chemical vapor deposition for the first time, and the absolute composition, oxidation mechanism, and optical properties were investigated. The absolute composition including hydrogen was performed by means of elastic recoil detection time of flight. It was found that the oxygen and fluorine contents in the film dramatically increased, but the hydrogen content decreased to below 4 at.% as the NF3 flow rate increased. The oxidation mechanism could be explained in terms of the incorporation of the activated residual oxygen species in the chamber into the film with unstable open structure by the fluorine-added plasma. It was shown that the density and optical properties such as refractive index, absorption coefficient, and optical energy gap depended on the film composition. The variations of the above properties for fluorinated silicon nitride film could be interpreted by the contents of fluorine and oxygen with high electronegativity.

scholarly journals The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 637
Author(s):  
Hongliang Li ◽  
Zewen Lin ◽  
Yanqing Guo ◽  
Jie Song ◽  
Rui Huang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Chemical Vapor ◽  
Wide Bandgap ◽  
Nonradiative Recombination ◽  
Very High Frequency ◽  
N Content ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
N Incorporation

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.

scholarly journals Investigations on the Optical Properties of InGaN/GaN Multiple Quantum Wells with Varying GaN Cap Layer Thickness

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Liang ◽  
Degang Zhao ◽  
Zongshun Liu ◽  
Jianjun Zhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Layer Thickness ◽  
Stark Effect ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Three Samples ◽  
Measurement Results ◽  
Cap Layer ◽  
The Difference

Abstract Three InGaN/GaN MQWs samples with varying GaN cap layer thickness were grown by metalorganic chemical vapor deposition (MOCVD) to investigate the optical properties. We found that a thicker cap layer is more effective in preventing the evaporation of the In composition in the InGaN quantum well layer. Furthermore, the quantum-confined Stark effect (QCSE) is enhanced with increasing the thickness of GaN cap layer. In addition, compared with the electroluminescence measurement results, we focus on the difference of localization states and defects in three samples induced by various cap thickness to explain the anomalies in room temperature photoluminescence measurements. We found that too thin GaN cap layer will exacerbates the inhomogeneity of localization states in InGaN QW layer, and too thick GaN cap layer will generate more defects in GaN cap layer.

scholarly journals Sulfophosphate Glass Doped with Er3+ and TiO2 Nanoparticles: Thermo-Optical Characterization by Photothermal Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 115
Author(s):  
Zeinab Ebrahimpour ◽  
Humberto Cabrera ◽  
Fahimeh Ahmadi ◽  
Asghar Asgari ◽  
Joseph Niemela
Keyword(s):  
Optical Properties ◽  
Tio2 Nanoparticles ◽  
Refractive Index Change ◽  
Optical Path Length ◽  
Beam Deflection ◽  
Time Resolved ◽  
Tio2 Nps ◽  
Amorphous Glass ◽  
Laser Media ◽  
Materials Used

In this work, time-resolved thermal lens and beam deflection methods were applied to determine the thermo-optical properties of Er3+ doped sulfophosphate glass in which different concentrations of Titanium dioxide (TiO2) nanoparticles (NPs) were embedded. Thermal diffusivity (D), thermal conductivity (κ), and the temperature coefficient of the optical path length (ds/dT) were determined as a function of NPs concentrations. Moreover, the growth of TiO2 NPs inside the amorphous glass matrix was evidenced by Transmission Electron Microscopy (TEM) images as well as through optical effects such as refractive index change of the glass. The outcomes indicated relatively high values for D and κ as well as a low ds/dT as required for most optical components used for laser media. The addition of TiO2 NPs with concentration of dopants up to 0.6 mol% improved the optical properties of the glass samples but did not affect its thermal properties. The results indicate that the enhanced optical and thermal performance of the proposed co-doped glass fits the quality standards for materials used in photonic devices.

scholarly journals Temperature Dependence of Stress and Optical Properties in AlN Films Grown by MOCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 698
Author(s):  
Wenwang Wei ◽  
Yi Peng ◽  
Jiabin Wang ◽  
Muhammad Farooq Saleem ◽  
Wen Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Compressive Stress ◽  
Sapphire Substrate ◽  
Light Transmission ◽  
Chemical Vapor ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Transmission Electron ◽  
Nano Patterning

AlN epilayers were grown on a 2-inch [0001] conventional flat sapphire substrate (CSS) and a nano-patterned sapphire substrate (NPSS) by metalorganic chemical vapor deposition. In this work, the effect of the substrate template and temperature on stress and optical properties of AlN films has been studied by using Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer and spectroscopic ellipsometry (SE). The AlN on NPSS exhibits lower compressive stress and strain values. The biaxial stress decreases from 1.59 to 0.60 GPa for AlN on CSS and from 0.90 to 0.38 GPa for AlN on NPSS sample in the temperature range 80–300 K, which shows compressive stress. According to the TEM data, the stress varies from tensile on the interface to compressive on the surface. It can be deduced that the nano-holes provide more channels for stress relaxation. Nano-patterning leads to a lower degree of disorder and stress/strain relaxes by the formation of the nano-hole structure between the interface of AlN epilayers and the substrate. The low crystal disorder and defects in the AlN on NPSS is confirmed by the small Urbach energy values. The variation in bandgap (Eg) and optical constants (n, k) with temperature are discussed in detail. Nano-patterning leads to poor light transmission due to light scattering, coupling, and trapping in nano-holes.

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