All-chemical vapor deposited graphene/silicon nitride TFTs

All-chemical vapor deposited silicon nitride / monolayer graphene TFTs have been fabricated. Polychromatic Raman spectroscopy shows high quality monolayer graphene channels with uniform coverage and significant interfacial doping at the source-drain contacts. Nominal mobilities of approximately 1900 cm 2V-1s-1 have been measured opening up a potentially useful platform for analogue and RFR-based applications fabricated through allchemical vapor deposition processes. © The Electrochemical Society.

On-chip switching of a silicon nitride micro-ring resonator based on digital microfluidics platform.

We demonstrate the switching of a silicon nitride micro ring resonator (MRR) by using digital microfluidics (DMF). Our platform allows driving micro-droplets on-chip, providing control over the effective refractive index at the vicinity of the resonator and thus facilitating the manipulation of the transmission spectrum of the MRR. The device is fabricated using a process that is compatible with high-throughput silicon fabrication techniques with buried highly doped silicon electrodes. This platform can be extended towards controlling arrays of micro optical devices using minute amounts of liquid droplets. Such an integration of DMF and optical resonators on chip can be used in variety of applications, ranging from biosensing and kinetics to tunable filtering on chip.

Ultrathin silicon nitride microring resonator for biophotonic applications at 970 nm wavelength

We experimentally demonstrate a high-Q ultrathin silicon nitride microring resonator operating at wavelength of 970 nm that is favorable for large variety of biophotonic applications. Implementation of thin device layer of 200 nm allows enhanced interaction between the optical mode and environment, while still maintaining high quality factor of resonator. In addition, we show the importance of spectral window around 970 nm to improve device sensing capability. © 2010 American Institute of Physics.

Ultra-thin silicon nitride microring resonator for biophotonic applications at 970nm wavelength

We experimentally demonstrate an ultra-thin silicon nitride microring resonator operating at wavelength of 970nm that is favorable for large variety of biophotonic applications. Optimization parameters for improved sensitivity and light-mater interaction are presented. © 2010 Optical Society of America.

Fracture Properties of LPCVD Silicon Nitride and Thermally Grown Silicon Oxide Thin Films From the Load-Deflection of Long Si3N4 and SiO2/Si3N4 Diaphragms

The bulge test is successfully extended to the determination of the fracture properties of silicon nitride and oxide thin films. This is achieved by using long diaphragms made of silicon nitride single layers and oxide/nitride bilayers, and applying comprehensive mechanical model that describes the mechanical response of the diaphragms under uniform differential pressure. The model is valid for thin films with arbitrary z-dependent plane-strain modulus and prestress, where z denotes the coordinate perpendicular to the diaphragm. It takes into account the bending rigidity and stretching stiffness of the layered materials and the compliance of the supporting edges. This enables the accurate computation of the load-deflection response and stress distribution throughout the composite diaphragm as a function of the load, in particular at the critical pressure leading to the fracture of the diaphragms. The method is applied to diaphragms made of single layers of 300-nm-thick silicon nitride deposited by low-pressure chemical vapor deposition and composite diaphragms of silicon nitride grown on top of thermal silicon oxide films produced by wet thermal oxidation at 950 degrees C and 1050 degrees C with target thicknesses of 500, 750, and 1000 mn. All films characterized have an amorphous structure. Plane-strain moduli E-ps and prestress levels sigma(0) of 304.8 +/- 12.2 GPa and 1132.3 +/- 34.4 MPa, respectively, are extracted for Si3N4, whereas E-ps = 49.1 +/- 7.4 GPa and sigma(0) = -258.6 +/- 23.1 MPa are obtained for SiO2 films. The fracture data are analyzed using the standardized form of the Weibull distribution. The Si3N4 films present relatively high values of maximum stress at fracture and Weibull moduli, i.e., sigma(max) = 7.89 +/- 0.23 GPa and m = 50.0 +/- 3.6, respectively, when compared to the thermal oxides (sigma(max) = 0.89 +/- 0.07 GPa and m = 12.1 +/- 0.5 for 507-nm-thick 950 degrees C layers). A marginal decrease of sigma(max) with thickness is observed for SiO2, with no significant differences between the films grown at 950 degrees C and 1050 degrees C. Weibull moduli of oxide thin films are found to lie between 4.5 +/- 1.2 and 19.8 +/- 4.2, depending on the oxidation temperature and film thickness.

Strong visible and infrared photoluminescence from Er-implanted silicon nitride films

Silicon nitride films were deposited by plasma-enhanced chemical-vapour deposition. The films were then implanted with erbium ions to a concentration of 8 x 10(20) cm(-3). After high temperature annealing, strong visible and infrared photoluminescence (PL) was observed. The visible PL consists mainly of two peaks located at 660 and 750 nm, which are considered to originate from silicon nanocluster (Si-NCs) and Si-NC/SiNx interface states. Raman spectra and HRTEM measurements have been performed to confirm the existence of Si-NCs. The implanted erbium ions are possibly activated by an energy transfer process, leading to a strong 1.54 mu m PL.

Bulge testing and fracture properties of plasma-enhanced chemical vapor deposited silicon nitride thin films

The mechanical properties and fracture behavior of silicon nitride (SiNx) thin film fabricated by plasma-enhanced chemical vapor deposition is reported. Plane-strain moduli, prestresses, and fracture strengths of silicon nitride thin film; deposited both oil a bare Si substrate and oil a thermally oxidized Si substrate were extracted using bulge testing combined with a refined load-deflection model of long rectangular membranes. The plane-strain modu i and prestresses of SiNx thin films have little dependence on the substrates, that is, for the bare Si substrate, they are 133 +/- 19 GPa and 178 +/- 22 MPa, respectively, while for the thermally oxidized substrate, they are 140 +/- 26 Gila and 194 +/- 34 MPa, respectively. However, the fracture strength values of SiNx films grown on the two substrates are quite different, i.e., 1.53 +/- 0.33 Gila and 3.08 +/- 0.79 GPa for the bare Si substrate a A the oxidized Si substrate, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over the edge, Surface, and volume of the specimens and fitted with the Weibull distribution function. For SiNx thin film produced oil the bare Si Substrate, the Volume integration gave a significantly better agreement between data and model, implying that the volume flaws re the dominant fracture origin. For SiNx thin film grown on the oxidized Si substrate, the fit quality of surface and edge integration was significantly better than the Volume integration, and the dominant surface and edge flaws could be caused by buffered HF attacking the SiNx layer during SiO2 removal. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

Photoluminescence of Er-doped hydrogenated amorphous silicon nitride

Er photoluminescence (Er PL) and dangling bonds (DBs) of annealed Er-doped hydrogenated amorphous silicon nitride (a-SiN:H(Er)) with various concentrations of nitrogen are studied in the temperature range 62-300 K. Post-annealing process is employed to change the DBs density of a-SiN:H(Er). PL spectra, DBs density and H, N concentrations are measured. The intensity of Er PL displays complicated relation with Si DBs density within the annealing temperature range 200-500 degreesC. The intensity of Er PL first increases with decreasing density of Si dangling bonds owing to the structural relaxation up to 250 degreesC, and continues to increase up to 350 degreesC even though the density of Si DBs increases due to the improvement of symmetry environment of Er3+. (C) 2003 Elsevier B.V. All rights reserved.

Fracture properties of PECVD silicon nitride thin films by long rectangular memrane bulge test

Bulge test combined with a refined load-deflection model for long rectangular membrane was applied to determine the mechanical and fracture properties of PECVD silicon nitride (SiNx) thin films. Plane-strain modulus E-ps prestress s(0), and fracture strength s(max) of SiNx thin films deposited both on bare Si substrate and on SiO2-topped Si substrate were extracted. The SiNx thin films on different substrates possess similar values of E-ps and s(0) but quite different values of s(max). The statistical analysis of fracture strengths were performed by Weibull distribution function and the fracture origins were further predicted.

EFFECT OF TOTAL HYDROGEN CONTENT IN SILICON-NITRIDE SENSITIVE FILM ON PERFORMANCE OF ISFET

Quantitative determinations of the hydrogen content and its profile in silicon nitride sensitive films by the method of resonant nuclear reaction have been carried out. At a deposition temperature of 825-degrees-C, hydrogen exists in an LPCVD silicon nitride sensitive film and the hydrogen content on its surface is in the range (8-16) x 10(21) cm-3, depending on the different deposition processes used. This hydrogen content is larger than the (2-3) x 10(21) cm-3 in its interior part, which is homogeneous. Meanwhile, we observe separate peaks for the chemical bonding configurations of Si-H and N-H bonds, indicated by the infrared absorption bands Si-O (1106 cm-1), N-H (1200 cm-1), Si-H-3 (2258 cm-1) and N-H-2 (3349 cm-1), respectively. The worse linear range of the ISFET is caused by the presence of oxygen on the surface of the silicon nitride sensitive film. The existence of chemical bonding configurations of Si-H, N-H and N-Si on its surfaces is favourable for its pH response.

MEV PROTON ELASTIC BACKSCATTERING ANALYSIS OF SILICON-NITRIDE AND OXIDE LAYERS ON SILICON

A simple method for the analysis of concentration ratios N/Si and O/Si in silicon nitride and oxide layers on silicon substrate is presented. 1.95-MeV proton elastic backscattering was used to determine the composition and density. A comparison with 2.1-MeV helium Rutherford backscattering measurements is given. Results are in good agreement with each other. The method is especially useful to analyze samples of 20 000 angstrom or thicker layers. We conclude that these two techniques are complementary for the measurements of samples with different thickness. A brief discussion has been given on results.

Photoluminescence spectroscopy of sputtering Er-doped silicon-rich silicon nitride films

Er-doped silicon-rich silicon nitride (SRN) films were deposited on silicon substrate by an RF magnetron reaction sputtering system. After high temperature annealing, the films show intense photoluminescence in both the visible and infrared regions. Besides broad-band luminescence centered at 780 nm which originates from silicon nanocrystals, resolved peaks due to transitions from all high energy levels up to ~2H_(11/2) to the ground state of Er~(3+) are observed. Raman spectra and HRTEM measurements have been performed to investigate the structure of the films, and possible excitation processes are discussed.