Si3 N4 Research Articles

Effect of Bulk Nitriding on Magnetic Properties of Iron

Results of a study of nitriding of iron with the use of boron, aluminum and silicon nitrides are presented. It is shown that the method suggested, which involves mixing of Fe powders with BN, AlN and Si3 N4, pressing of the briquette, heating in a nitrogen atmosphere to 1550°C, 3-h holding, and cooling with the furnace, gives specimens consisting of two parts, i.e., ceramic and metallic ones. The structure of the metallic part is represented by primary precipitates of iron and eutectic colonies of type Fe – Fe2 B in which a part of boron is substituted with nitrogen. The metallic specimens possess enhanced hardness and relatively high coercivity comparable to that of nitrided thin films and nanosize powders.

Comparison of polyetheretherketone versus silicon nitride intervertebral spinal spacers in a caprine model

Polyetheretherketone (PEEK) is commonly used as a spinal spacer for intervertebral fusion surgery. Unfortunately, PEEK is bioinert and does not effectively osseointegrate into living bone. In contrast, comparable spacers made of silicon nitride (Si3 N4 ) possess a surface nanostructure and chemistry that encourage appositional bone healing. This observational study was designed to compare the outcomes of these two biomaterials when implanted as spacers in an adult caprine model. Lumbar interbody fusion surgeries were performed at two adjacent levels in eight adult goats using implants of PEEK and Si3 N4 . At six-months after surgery, the operative and adjacent spinal segments were extracted and measured for bone fusion, bone volume, bone-implant contact (BIC) and soft-tissue implant contact (SIC) ratios, and biodynamic stability. The null hypothesis was that no differences in these parameters would be apparent between the two groups. Fusion was observed in seven of eight implants in each group with greater bone formation in the Si3 N4 group (52.6%) versus PEEK (27.9%; p = 0.2). There were no significant differences in BIC ratios between PEEK and Si3 N4 , and the biodynamic stability of the two groups was also comparable. The results suggest that Si3 N4 spacers are not inferior to PEEK and they may be more effective in promoting arthrodesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000-000, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 688-699, 2019.

Incorporating Si3 N4 into PEEK to Produce Antibacterial, Osteocondutive, and Radiolucent Spinal Implants.

Polyetheretherketone (PEEK) is a popular polymeric biomaterial which is primarily used as an intervertebral spacer in spinal fusion surgery; but it is developed for trauma, prosthodontics, maxillofacial, and cranial implants. It has the purported advantages of an elastic modulus which is similar to native bone and it can be easily formed into custom 3D shapes. Nevertheless, PEEK's disadvantages include its poor antibacterial resistance, lack of bioactivity, and radiographic transparency. This study presents a simple approach to correcting these three shortcomings while preserving the base polymer's biocompatibility, chemical stability, and elastic modulus. The proposed strategy consists of preparing a PEEK composite by dispersing a minor fraction (i.e., 15 vol%) of a silicon nitride (Si3 N4 ) powder within its matrix. In vitro tests of PEEK composites with three Si3 N4 variants-β-Si3 N4 , α-Si3 N4 , and β-SiYAlON-demonstrate significant improvements in the polymer's osteoconductive versus SaOS-2 cells and bacteriostatic properties versus gram-positive Staphylococcus epidermidis bacteria. These properties are clearly a consequence of adding the bioceramic dispersoids, according to chemistry similar to that previously demonstrated for bulk Si3 N4 ceramics in terms of osteogenic behavior (vs both osteosarcoma and mesenchymal progenitor cells) and antibacterial properties (vs both gram-positive and gram-negative bacteria).

Theoretical Investigation of Tensile-Strained GeSn/SiGeSn Multiple Quantum Well Laser Wrapped in Si 3N4 Liner Stressor

A tensile-strained GeSn/SiGeSn multiple quantum well (MQW) laser wrapped in Si3N4 liner stressor is designed and characterized theoretically. A biaxial tensile strain is introduced into the GeSn/SiGeSn MQW laser by the Si3N4 liner stressor. The boosting effects of tensile strain on the threshold current density J th and optical gain in GeSn/SiGeSn lasers are attributed to the modulation of energy band structure and carrier distribution in the GeSn wells. Tensile-strained Ge0.90Sn 0.10/Si0.161Ge0.695Sn0.144 MQW laser wrapped in 500 nm Si3N 4 liner stressor achieves a J th reduction from 476 to 168 A/cm2 and a significant enhancement of optical gain, as compared to the relaxed control device without Si3N4 . The design of GeSn/SiGeSn MQW structure wrapped in Si3N4 liner stressor provides a practical way to realize high performance GeSn based mid-infrared laser.

Photocurable acrylate-based composites with enhanced thermal conductivity containing boron and silicon nitrides

Boron nitride (BN) and silicon nitride (Si3N4) are very promising particulate fillers for production of photocurable composites dedicated to thermally conductive and electrically insulating protective coatings. Composites containing crosslinked methacrylate-based matrices filled with BN or Si3N4 (in amounts up to 5 wt%) were prepared in a fast in situ photocuring process with high conversion (>90%). The monomers were polyethylene glycol dimethacrylate and mono-methacrylate (50/50 by weight mixture). Investigations included determination of properties of the monomer/filler compositions, photocuring kinetics and thermal, conductive and mechanical properties of the resulting composites. It was found that addition of the fillers improves polymerization kinetics and mechanical properties compared to the pure polymer matrix. Despite the very low loading level a substantial improvement in thermal conductivity was obtained: a 4-fold increase after addition of only 2 wt% of Si3 N4 and 2.5-fold increase after addition of 0.5 wt% of BN. SEM and AFM imaging (with nanoscopic Young’s modulus determination) revealed good matrix-filler adhesion for the both types of fillers, tendency of the particles to be preferentially located in the bulk rather than at the interface and formation of thermally conducting paths (for the Si3N4 filler).

Photonic Crystal Phosphors Integrated on a Blue LED Chip for Efficient White Light Generation.

Following the proof-of-concept experiment in the unit structure level, photonic crystal (PhC) phosphors-structurally engineered phosphor materials based on the nanophotonics principles-are integrated with a blue light-emitting diode (LED) chip to demonstrate a compact and efficient white light source. Red- or green-emitting CdSe-based colloidal quantum dots (CQDs) are coated on a Si3 N4 thin-film grating to fabricate PhC phosphors. The underlying PhC structure is designed such that the photonic band-edge modes at the zone center (k∣∣ = 0) are tuned to the energy of the blue excitation photons. By progressively stacking the PhC phosphor plates on a blue LED chip, the blue, green, and red emission intensities can be tightly controlled to obtain white light with the desired properties. The chromaticity coordinates, (0.332, 0.341), and correlated color temperature, 5500 K, are obtained from a stack of 3 red and 11 green PhC phosphor plates; in contrast, a stack of 5 red and 16 green reference phosphor plates are required to generate a similar white light. Overall, the PhC phosphors produce 8% higher total emission intensity out of 33% less amount of CQDs than the reference phosphors.

Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model.

While silicon nitride (Si3 N4 ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si3 N4 implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si3 N4 implants displayed significant reductions in adherent bacteria versus machined Si3 N4 (2.6 × 104 vs. 8.7 × 104 CFU, respectively; p < 0.0002). Moreover, SEM imaging demonstrated that MRSA cannot directly adhere to native as-fired Si3 N4 . Subsequently, a cross-sectional study was completed in which sterile or MRSA contaminated as-fired and machined Si3 N4 implants were inserted into the tibiae of 8-week old female Balb/c mice, and harvested on day 1, 3, 5, 7, 10, or 14 post-operatively for SEM. The findings demonstrated that the antimicrobial activity of the as-fired implants resulted from macrophage clearance of the bacteria during biofilm formation on day 1, followed by osseointegration through the apparent recruitment of mesenchymal stem cells on days 3-5, which differentiated into osteoblasts on days 7-14. In contrast, the antimicrobial behavior of the machined Si3 N4 was due to repulsion of the bacteria, a phenomenon that also limited osteogenesis, as host cells were also unable to adhere to the machined surface. Taken together, these results suggest that the in vivo biological behavior of Si3 N4 orthopaedic implants is driven by critical features of their surface nanotopography. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3413-3421, 2017.

Superconducting Nanowire Single Photon Detector for Coherent Detection of Weak Signals

Traditional photon detectors are operated in the direct detection mode, counting incident photons with a known quantum efficiency. Here, we have investigated a superconducting nanowire single photon detector (SNSPD) operated as a photon counting mixer at telecommunication wavelength around 1.5 μm. This regime of operation combines excellent sensitivity of a photon counting detector with excellent spectral resolution given by the heterodyne technique. Advantageously, we have found that low local oscillator (LO) power of the order of hundreds of femtowatts to a few picowatts is sufficient for clear observation of the incident test signal with the sensitivity approaching the quantum limit. With further optimization, the required LO power could be significantly reduced, which is promising for many practical applications, such as the development of receiver matrices or recording ultralow signals at a level of less-than-one-photon per second. In addition to a traditional NbN-based SNSPD operated with normal incidence coupling, we also use detectors with a travelling wave geometry, where a NbN nanowire is placed on the top of a Si 3N4 nanophotonic waveguide. This approach is fully scalable and a large number of devices could be integrated on a single chip.

Development of a SiYAlON glaze for improved osteoconductivity of implantable medical devices.

The application of bioactive coatings onto orthopaedic appliances is commonly performed to compensate for the otherwise bioinert nature of medical devices and to improve their osseointegration. Calcium phosphates, hydroxyapatite (HAp), and bioglasses are commercially available for this purpose. Until recently, few other inorganic compounds have been identified with similar biofunctionality. However, silicon nitride (Si3 N4 ) has emerged as a new orthopaedic material whose unique surface chemistry also enhances osteoconductivity. Recent research has confirmed that its minority intergranular phase, consisting of silicon yttrium aluminum oxynitride (SiYAlON), is principally responsible for this improvement. As a result, it was hypothesized that SiYAlON itself might serve as an effective osteoconductive coating or glaze for medical devices. To test this hypothesis, a process inspired by traditional ceramic whiteware glazing was developed. A slurry containing ingredients similar to the intergranular SiYAlON composition was applied to a Si3 N4 surface, which was then subjected to a heat treatment to form a glaze. Various analytical tools were employed to assess its chemistry and morphology. It was found that the glaze was comprised predominately of Y5 Si3 O12 N, a compound commonly referred to as N-apatite, which is isostructural to native HAp. Subsequent exposure of the glazed surface to acellular simulated body fluid led to increased deposition of biomimetic HAp-like crystals, while exposure to Saos-2 osteosarcoma cells in vitro resulted in greater HAp deposition relative to control samples. The observation that SiYAlON exhibits enhanced osteoconductivity portends its potential as a therapeutic aid in bone and tissue repair. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1084-1096, 2018.

Nanocomposites through the Chemistry of Single-Source Precursors: Understanding the Role of Chemistry behind the Design of Monolith-Type Nanostructured Titanium Nitride/Silicon Nitride.

Monolith-type titanium nitride/silicon nitride nanocomposites, denoted as TiN/Si3 N4 , have been prepared by a reaction of polysilazanes with a titanium amide precursor, warm pressing of the resultant polytitanosilazanes, and subsequent pyrolysis of the green bodies at 1400 °C. Initially, a series of polytitanosilazanes was synthesized and the role of the chemistry behind their synthesis was studied in detail by using solid-state NMR spectroscopy, elemental analysis, and molecular-weight measurements. The intimate relationship between the chemistry and the processability of these precursors is discussed. Polytitanosilazanes display the appropriate requirements for facile processing in solution and as a melt, but they must be treated with liquid ammonia to be adapted for solid-state processing, that is, warm-pressing, to design dense and mechanically stable structures after pyrolysis. We provide a comprehensive mechanistic study of the nanocomposite conversion based on solid-state NMR spectroscopy coupled with thermogravimetric experiments. HRTEM images coupled with XRD and Raman spectroscopy confirmed the unique nanostructural features of the nanocomposites, which appear to be a result of the molecular origin of the materials. The as-obtained samples are composed of an amorphous Si3 N4 matrix, in which TiN nanocrystals are homogeneously formed in situ in the matrix during the process. The hardness and Young moduli were measured and are discussed.

Characterizing the Compression Behavior of Al2O3/Si3N4 Nano Sized Particulate Reinforced Ceramic Matrix Composites

Objectives: Nano sized objects are exhibiting extra ordinary potential in all the aspects of properties. Objective of this work is to develop the composite of alumina reinforced with nano sized silicon nitride particles to analyze the compression behaviour of the developed composite materials against compacting pressure and % of reinforcement. Methods: Powder metallurgical techniques were used to manufacture the sample specimens of composites. The specimens were prepared with various proportions Si3 N4 reinforcement ranges from 1 wt% to 20 wt%. Alumina was functionalized with 5 wt% of Poly Vinyl Alcohol (PVA) at 80°C using water as plasticizer to enhance the dispersion and flow behaviour essential for forming the material. The composites were cold formed in two cycles where compacting pressure was maintained as 510 MPa and 725 MPa. The sintering temperature was maintained as 1400°C for soaking period of 30 minutes. Findings: The results revealed that the reinforced composites showed 35% more compressive strength than unreinforced monolithic material. It was found that the reinforcement content of silicon nitride increased the compressive strength of the composite as expected. The barrelling behaviour was not observed during compression. The compressive strength of monolithic alumina at 725 MPa was 0.7 times greater than of 510 MPa. It was observed that 12.5% of reinforcement experienced maximum peak load of failure. The 1400°C for sintering was observed as not sufficient to make plastic flow in powder metallurgical preforms. Application/Improvements: The betterment in result can be achieved by increasing the sintering temperature to 1800°C for soaking time 30 minutes. This study reveals that this particular combination of ceramic matrix composites exhibit better results in compressive behaviour. This can be further analyzed for wear and can be used as outstanding material in hybrid ceramic bearings. Keywords: Ceramic Matrix Composites, Compression Behaviour, Hybrid Bearings, Powder Metallurgy, PVA

Experimental Demonstration of Directive Si3N4 Optical Leaky Wave Antennas With Semiconductor Perturbations

Directive optical leaky wave antennas (OLWAs) fabricated in CMOS-compatible semiconductor planar waveguide technology have the potential to provide high directivity with electrical tunability promising for modulation and switching capabilities. We experimentally demonstrate directive radiation from a silicon nitride (Si3N 4) waveguide-based OLWA. The OLWA design comprises a crystalline silicon (Si) nanowire array buried inside a Si 3N4 waveguide. Each Si nanowire has a width of 260 nm and a height of 150 nm. The OLWA is designed to exhibit a directive radiation pattern at telecom wavelengths. The measured radiation pattern at the wavelength 1550 nm has its maximum emission intensity at the angle of 85.1° relative to the waveguide axis and a half-power beam width of approximately 5.0°, which are consistent with our theoretical predictions. The results indicate that the TM mode is more radiative than the TE mode in our fabricated devices. Also, the radiation pattern of the measured OLWA shows dependence on wavelength, which is typical of leaky wave antennas. The device is promising in chip-to-space optical interconnect applications.

Effects of additives on properties of Zr50Al15Ni10Cu25amorphous powders in low-pressure sintering

Amorphous Zr50 Al15 Ni10 Cu25 powders were prepared by mechanical alloying technique from low-purity raw materials. The beneficial effects of a certain amount of external additives such as C, Si3 N4 and SiC powders added to the amorphous powders on the thermal stability, densification and mechanical properties of the Zr50 Al15 Ni10 Cu25 amorphous powders after low-pressure sintering were investigated. The blended powers were hand-pressed into bars in the air under 35 MPa pressure. The preformed bars were sintered in an argon atmosphere under low pressure. The samples were characterized by XRD, SEM, TEM, DSC and tensile testing. The results suggest that the crystallization process of Zr50 Al15 Ni10 Cu25 during sintering could be inhibited for the increase in activation energy when the proper amount of external particles was added to the matrix. Furthermore, suitable additives could help to densify the matrix and improve its mechanical properties in the low-pressure sintering process.

Local Fracture Toughness of Si3N4 Ceramics Measured using Single‐Edge Notched Microcantilever Beam Specimens

Local fracture toughness gives us useful and important information to understand and improve mechanical properties of bulk ceramics. In this study, the local fracture toughness of silicon nitride (Si3N4) ceramics was directly measured using single‐edge notched microcantilever beam specimens prepared by the focused ion beam technique. The measured fracture toughness of grain boundary of the Si3N4 ceramics is higher than the fracture toughness of SiAlON glass, which exists in the grain boundaries of Si3N4 ceramics. It is also shown that the fracture toughness of grain boundary depends on the rare earth oxide added as a sintering aid, which is expected in terms of the difference in the grain‐boundary structure. The fracture toughness of a single β‐Si3N4 grains is higher than the grain‐boundary fracture toughness. It was also higher than the value estimated from ab initio calculations and surface energy, which means that any dissipative energy should be included in the fracture toughness of a grain in spite of the brittle fracture in Si3N4. The fracture toughness of polycrystals of Si3N4 ceramics measured using single‐edge notched microcantilever beam specimens is intermediate between those of grains and grain boundaries, and it agrees with the estimated initial value of the Rcurve, KI0, in Si3N4 ceramics.

INVESTIGATION OF SEMICONDUCTORS STRUCTURES FOR DEVELOPMENT OF pHSENSITIVE FIELD EFFECT TRANSISTORS

PH-sensitivity, stability and drift of semiconductors structures with various quality and type of surface dielectric layer have been investigated. Their parameters for creation of pH-sensitive field effect transistors were optimised. The best results were obtained for two-layer structure of dielectric that consists of SiO2 and Si3 N4 . These structures were proposed for development of pHsensitive field effect transistors. The best characteristics were shown by transducers created at R&D Institute “Microdevice” (Kiev, Ukraine).

INTENSE UV ENRICHED PHOTO DETECTION BY HIGHER ENERGY EDGE ATTUNED COATING ON CSI DETECTOR

Solar UV detector industrial applications and monit oring is potential approach for technology based in dustrial development and ecosystem management aspects. Respect to visible spect rum both shorter and longer line width are not so p romising for solar energy detecting/ harvesting by using Si technology. For l ower energy edge of UV band absorption process, uti lization of UV compatible higher energy edge reaping supportive thickness of additional Si 3N4 layer on SiO 2 coating layer for crystalline c-Si detector is found promising. As compared to single SiO 2 coating layer or bared c-Si cell, applications of S iO 2+Si 3N4 double coating layer enhancement of the detector current or responsivity is specific ally observed. Compare to lower energy edge of sola r spectrum, UV (A-B) band enhanced energy conversion slant is found attractiv e. In this article, using ≤60 nm SiO 2 +Si 3N4harmonized coating layers on P + N, N + P and P + IN Si based detector, very intense UV band response is realized. It appears that tiny i-layer with minimum n-doping in P + iN structure as compared to the P + N detector, increases the conversion efficiency. Co mpared to P + N detector N + P detector

터널 산화막 두께에 따른 Al2O3/Y2O3/SiO2다층막의 메모리 특성 연구

Conventional SONOS (poly-silicon/oxide/nitride/oxide/silicon) type memory is associated with a retention issue due to the continuous demand for scaled-down devices. In this study, Al₂O3/Y₂O₃/SiO₂ (AYO) multilayer structures using a high-k Y₂O₃ film as a charge-trapping layer were fabricated for nonvolatile memory applications. This work focused on improving the retention properties using a Y₂O₃ layer with different tunnel oxide thickness ranging from 3 nm to 5 nm created by metal organic chemical vapor deposition (MOCVD). The electrical properties and reliabilities of each specimen were evaluated. The results showed that the Y₂O₃ with 4 nm SiO₂ tunnel oxide layer had the largest memory window of 1.29 V. In addition, all specimens exhibited stable endurance characteristics (program/erasecycles up to 104) due to the superior charge-trapping characteristics of Y₂O3. We expect that these highk Y₂O₃ films can be candidates to replace Si₃ N₄ films as the charge-trapping layer in SONOS-type flash memory devices.

Millimeter wave transmission spectroscopy of gated two-dimensional hole systems

We developed a differential transmission to study cyclotron resonance of GaAs/AlxGa1−xAs two-dimensional hole samples. The technique utilizes a modulated AuPd gate isolated by a Si3 N4 dielectric from the sample, which is irradiated opposite the gate by millimeter waves ranging from 2 to 40 GHz. This technique effectively removes the background signal and yields a hole effective mass of 0.41me with a cyclotron scattering time of ∼20 ps, consistent with the previous results using different techniques.

Comprehensive Study of Pi-Gate Nanowires Poly-Si TFT Nonvolatile Memory With an HfO $_2$ Charge Trapping Layer

This work demonstrates the feasibility of a polycrystalline silicon thin-film transistor (poly-Si TFTs) nonvolatile memory (NVM) that utilizes a Pi-shaped gate (Pi-gate) and multiple nanowire channels with a HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> charge-trapping layer. The TFT NVM with the Pi-gate nanowires (NWs) structure has a higher program/erase (P/E) efficiency than that of the conventional single-channel TFT NVM; the memory window can achieve 2.3 V, only needs a programming time of 1 μs. This high P/E efficiency follows from the improved gate control of the Pi-gate structure. A Pi-gate NWs poly-Si TFT NVM with a Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> charge-trapping layer was also fabricated. Since HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> has a deeper conduction band than Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , the device with the HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> charge-trapping layer has a higher programming efficiency and the better retention characteristics than that with the Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> charge-trapping layer. Additionally, the high programming efficiency allows the device with the HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> charge-trapping layer to undergo more P/E cycles than that with the Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> charge-trapping layer.

Crystalline and liquid Si3N4characterization by first-principles molecular dynamics simulations

Silicon nitride (Si3 N4 ) has a wide range of engineering applications where its mechanical and electronic properties can be effectively exploited. In particular, in the microelectronics field, the amorphous silicon nitride films are widely used as charge storage layer in metal-alumina-nitrideoxide nonvolatile memory devices. Atomic structure of amorphous silicon nitride is characterized by an high concentration of traps that control the electric behavior of the final device by the trappingde-trapping mechanism of the electrical charge occurring in its traps. In order to have a deep understanding of the material properties and, in particular, the nature of the electrical active traps a detailed numerical characterization of the crystalline and liquid phases is mandatory. For these reasons first-principles molecular dynamics simulations are extensively employed to simulate the crystalline Si3 N4 in its crystalline and liquid phases. Good agreement with experimental results is obtained in terms of density and formation entalpy. Detailed characterization of c-Si3 N4 electronic properties is performed in terms of band structure and band gap. Then constant temperature and constant volume first-principles molecular dynamics is used to disorder a stoichiometric sample of Si3 N4 . Extensive molecular dynamics simulations are performed to obtain a reliable liquid sample whose atomic structure does not depend on the starting atomic configuration. Detailed characterization of the atomic structure is achieved in terms of radial distribution functions and total structure factor.