2217 results about "Silicon nitride" patented technology

The invention discloses high-toughness ultrathin flexible glass and a preparation method thereof, and relates to the technical field of glass manufacturing. The ultrathin flexible glass is prepared from the following raw materials: silicon dioxide, aluminum oxide, lithium oxide, sodium oxide, magnesium oxide, a modified nano reinforced phase, a high-temperature melting regulator and cerium dioxide. The modified nano reinforced phase is prepared by the following steps: pre-treating silicon carbide and silicon nitride with hydrochloric acid, and mixing with nano zirconium oxide to obtain a mixture; and modifying the mixture with a silane coupling agent to obtain the modified nano reinforced phase. The high-temperature melting regulator is a mixture of lithium borate, sodium sulfate and lithium fluoride. The preparation method of the ultra-thin flexible glass comprises the following steps: preparing the modified nano reinforced phase, melting and homogenizing the glass, forming the glass substrate, and preparing the ultra-thin flexible glass. The ultra-thin flexible glass prepared by the invention has relatively high fracture toughness and structural rigidity, excellent flexibility and bending fatigue durability, and excellent thermal shock resistance.

The invention provides a low-compression-stress low-density heat-conducting gasket and a preparation method thereof.The heat-conducting gasket is prepared from, by weight, 100-300 parts of vinyl silicone oil, 1-3 parts of end chain hydrogen-containing silicone oil, 2-6 parts of side chain hydrogen-containing silicone oil, 0.2-0.6 part of platinum catalyst, 300-700 parts of heat-conducting filler, 0.1-0.5 part of coupling agent and 0.1-0.5 part of inhibitor. Wherein the vinyl silicone oil is prepared by matching two kinds of vinyl-terminated polydimethylsiloxane with different viscosities and vinyl contents; and the heat-conducting filler is a ternary combination of spherical aluminum oxide, spherical boron nitride and beta-type silicon nitride with a lubricating function. The preparation method comprises the following steps: adding the raw materials into stirring equipment, controlling the vacuum degree during stirring by adopting staged negative pressure, stirring under the conditions that the negative pressure is less than or equal to-0.095 MPa,-0.06 to-0.07 MPa and less than or equal to-0.095 MPa in sequence, fully mixing the materials, clustering, transferring to a calender, and carrying out high-temperature vulcanization molding at 120-140 DEG C. The heat-conducting gasket has the characteristics of low compression stress and low density, and the production efficiency is remarkably improved.

The invention discloses a silicon nitride ceramic-based composite material and a preparation method thereof, and relates to the technical field of silicon nitride ceramics. The silicon nitride ceramic-based composite material is prepared from silicon dioxide coated modified boron nitride and resin composite phase change microcapsules, Si3N4-C coated Al2O3 core-shell fiber aerogel, nano yttrium oxide and polyvinyl butyral, the silicon dioxide coated modified boron nitride and resin composite phase change microcapsules are stably attached to the surface of the Si3N4-C coated Al2O3 core-shell fiber aerogel in a chemical bonding and mechanical interlocking mode, the interface bonding strength is enhanced, the risk of phase separation is reduced, the combination effect of the silicon dioxide coated modified boron nitride and resin composite phase change microcapsules and the Si3N4-C coated Al2O3 core-shell fiber aerogel is better exerted, and the composite phase change effect of the silicon dioxide coated modified boron nitride and resin composite phase change microcapsules is improved. According to the present invention, the fracture toughness can be improved through fiber toughening, aerogel pore and microcapsule stress dispersion, the high temperature resistance can be improved through the low thermal conductivity of the aerogel and the heat absorption effect of the microcapsule, the mechanical property of the silicon nitride can be significantly improved through multiple ways and multiple modes, and the high temperature resistance can be effectively enhanced.

The invention provides titanium-containing anhydrous stemming for a blast furnace and a preparation method of the titanium-containing anhydrous stemming, and belongs to the technical field of refractory materials for the blast furnace. The titanium-containing anhydrous stemming for the blast furnace comprises the following raw materials: 40-60 parts of titanium corundum, 5-15 parts of silicon carbide, 10-20 parts of ferro-silicon nitride fine powder, 5-15 parts of titanium dioxide fine powder, 5-15 parts of vanadium-titanium slag fine powder, 5-10 parts of coke fine powder, 1-5 parts of monatomic silicon fine powder, 1-5 parts of ball clay micro powder, 1-5 parts of aluminum nitrate micro powder and 1-2 parts of magnesium alon micro powder. Gas-phase substances of Si (g), Al (g) and Mg (g) can be formed in the stemming at high temperature by the monatomic silicon fine powder and the MgAlON micro powder in the raw materials and react with CO and N2 in the environment to generate ceramic whiskers such as SiC, Si3N4, AlN and MgAl2O4, and the generated ceramic whiskers are distributed in a staggered manner and are filled in pores of the stemming, so that the high-temperature strength and the volume stability of the stemming are remarkably improved.

The invention relates to the technical field of metal wire processing, and discloses a high-performance metal wire plastic coating process for aerospace engineering, which comprises the following steps: carrying out base material type selection on a metal wire, and carrying out surface treatment of precise cleaning, etching and depth gradient activation; a Ti-Cr alloy and graphene-copper composite transition layer is deposited through a magnetron sputtering technology, and a multi-layer coating structure is formed through electrostatic spraying of a base coating, a fluidized bed dipping function layer and high velocity oxy-fuel spraying of a nano composite coating in sequence; the molybdenum-gold composite sealing layer is prepared by adopting an electric arc spraying technology, and is subjected to vacuum ultraviolet curing enhancement, high-temperature gradient annealing, gradient sintering and vacuum curing treatment; and heat radiation on the surface of the coating is enhanced through laser-induced micro-nano structure regulation and silicon nitride film sputtering. Through collaborative optimization of base material treatment, coating construction, function strengthening and quality control, the interface bonding strength, the comprehensive performance and the environmental adaptability of the spaceflight metal wire coating are remarkably improved, and the service life of the spaceflight metal wire coating is remarkably prolonged.

The invention discloses a laser wireless energy transmission system based on a vertical tracking structure and double-stage global optimization and a control method, and belongs to the technical field of photoelectric energy conversion and intelligent control. Aiming at the technical bottlenecks of high reflection loss of a photovoltaic array and MPPT failure caused by multi-peak characteristics due to non-uniform irradiation in the existing laser wireless transmission system, the invention provides three innovations: (1) designing a two-degree-of-freedom vertical tracking type photovoltaic array, and adjusting the pitch angle and azimuth angle of a photovoltaic panel in real time through a servo motor driving holder; a silicon nitride anti-reflection coating (the refractive index is smaller than or equal to 1.8) and a laser positioning sensor are combined to construct an incident angle deviation dynamic compensation model, and the reflection loss rate is reduced to be lower than 5%; (2) putting forward a global MPPT dual-stage optimization algorithm, dividing a voltage interval based on irradiation non-uniformity in a coarse positioning stage and generating an optimal candidate solution, and adopting an improved particle swarm algorithm (introducing an inertia weight dynamic adjustment mechanism and a local extreme value escape strategy) in a fine search stage to realize that the global maximum power point tracking precision reaches 99.2% in a multi-peak scene; and (3) establishing a reflection loss-power coupling control model, and solving the problems of tracking delay and energy oscillation of a traditional system through angle adjustment of the photovoltaic panel and closed-loop feedback of MPPT (Maximum Power Point Tracking) output. Compared with the prior art, the comprehensive efficiency of the system is improved by 18.6% under the dynamic irradiation condition, and the system is suitable for space laser power supply and mobile equipment wireless charging scenes.

The invention relates to the technical field of ceramic materials, in particular to a method for reducing the surface roughness of a silicon nitride instant-fired sheet, which comprises the following steps: S1, mixing alpha-silicon nitride, beta-silicon nitride, absolute ethyl alcohol and herring fish oil, grinding and dispersing to obtain basic mixed powder; s2, mixing, grinding and dispersing the filling mixed powder, absolute ethyl alcohol and herring fish oil, then carrying out filter pressing and drying, calcining and regrinding to obtain ground filling mixed powder; s3, mixing and ball-milling the basic mixed powder, the ground filling mixed powder, a solvent, an adhesive, a plasticizer and a dispersing agent to obtain slurry; s4, casting the slurry into a film; s5, attaching the thin film to the surface of the silicon nitride green body, and pressing the silicon nitride green body into a whole piece through an isostatic press to obtain a pressed green body; s6, a boron nitride isolation layer is printed on the surface of the pressed green body, and the green body with the isolation layer is obtained; and S7, stacking the green bodies with the isolating layers, and then carrying out adhesive removal and sintering reaction to obtain the silicon nitride ceramic chip.

The invention belongs to the technical field of silicon carbide ceramic product preparation, and provides a semiconductor recrystallized silicon carbide product and a preparation method thereof. The preparation method comprises the following steps: mixing preparation raw materials containing silicon carbide with water, and sequentially forming and sintering to obtain the semiconductor recrystallized silicon carbide product. The halogen-containing gas is introduced in the sixth heat preservation process of sintering, Fe ions, Al ions and Ca ions in the silicon carbide product can be removed, and the purity of the recrystallized silicon carbide product is obviously improved. Data of the embodiment shows that the purity of the obtained recrystallized silicon carbide product is greater than or equal to 4N. Furthermore, the pressure of the fifth temperature rise is controlled to be 102500-11000 Pa, and the pressure of the sixth temperature rise is controlled to be 102500-11000 Pa, so that the surface roughness of the recrystallized silicon nitride product is reduced, and the surface roughness of the recrystallized silicon carbide product is less than Ra10.

The invention discloses a preparation method of low-temperature rapid densification silicon nitride ceramic based on an aluminum oxide-yttrium oxide composite sintering aid, and aims to solve the problems of high temperature, high energy consumption, difficult densification and the like in the existing Si3N4 ceramic preparation. The preparation method comprises the following steps: 1, mixing alpha-Si3N4 powder, Y2O3 powder and Al2O3 powder, and carrying out ball milling dispersion to obtain mixed powder; 2, carrying out rotary evaporation drying on the mixed powder under a vacuum condition; 3, carrying out heat preservation treatment under the conditions of 1600-1700 DEG C and 40-60 MPa through a spark plasma sintering process; and 4, demolding after cooling. Under the action of the Al2O3-Y2O3 composite sintering aid, phase transformation from alpha-Si3N4 to beta-Si3N4 is remarkably promoted, the relative density of the ceramic reaches 97%-99%, the fracture toughness of the ceramic is 5.21 MPa.m < 1 / 2 >, and the bending strength of the ceramic is 924.99 MPa.

The invention provides a manufacturing method of a shallow trench isolation structure. The manufacturing method comprises the following steps: patterning a pad oxide layer-silicon nitride layer laminated structure based on a photomask to obtain a first mask opening; etching the substrate to obtain an isolation groove; carrying out a pull-back process; depositing a sacrificial layer material in the isolation trench and the first mask opening; forming a shielding layer; patterning the shielding layer based on the photomask to obtain a second mask opening; removing the sacrificial layer material in the isolation groove and obtaining a sacrificial side wall located on the side wall of the opening of the silicon nitride layer; removing the shielding layer and depositing a silicon oxide layer in the isolation groove and the first mask opening; and removing the silicon nitride layer, the liner oxide layer and the sacrificial side wall. According to the method, the first mask opening and the second mask opening are formed in different steps based on the same photomask by adopting the pull-back process, the sacrificial side wall on the side wall of the opening of the silicon nitride layer is used for protecting the trench oxide layer from being lost in the subsequent removal process of the liner oxide layer, and the problem of a sunken region at the top edge of the shallow trench isolation region can be avoided or improved.

The invention provides a high-density photoelectric common connection pinboard based on a low-loss silicon nitride grating coupler. The invention aims to overcome the difficulty that the existing photoelectric heterogeneous chip is difficult to integrate, stack and package, and realizes high-density interconnection between the chip and the interposer by using a grating coupling structure and a silicon through hole technology, thereby realizing high-integration low-loss packaging of the heterogeneous chip on the interposer. According to the invention, high-efficiency optical interconnection between the heterogeneous chip and the photoelectric co-connection intermediate layer is realized through the high-efficiency grating coupler, and high-density electrical interconnection between the chip and the photoelectric co-connection intermediate layer is realized through the TSV technology and the RDL technology. Meanwhile, the optical interconnection efficiency between the interposer and the chip is improved by utilizing the electrode patterning advantage of the RDL technology, and the self-alignment between the chip and the interposer is realized. The method has extremely high compatibility to the packaging scene of the existing photoelectric heterogeneous chip, so that the method has great significance in improving the integration density and reducing the interconnection loss of a photoelectric heterogeneous integrated system and promoting the practicability of the photoelectric heterogeneous integrated system.

The invention discloses a silicon nitride ceramic thermal conductivity prediction method based on machine learning coding-free feature processing. The method comprises the following steps: acquiring a data set; declaring a chemical character string field of the sintering aid as a disordered data type, and preprocessing other numerical characteristics at the same time; keeping the field of the sintering aid as a disordered data type, and preprocessing other numerical values; selecting a gradient lifting decision tree model supporting native processing category features as a prediction model and performing optimization; a to-be-predicted formula-process parameter combination is input into the optimized prediction model, a thermal conductivity prediction value is output in real time, and the to-be-predicted formula-process parameter combination is directly input into the model through an original chemical formula character string. The invention further discloses a device for implementing the method, computer equipment and a readable storage medium. According to the invention, the original chemical formula of the sintering aid can be directly utilized, and the thermal conductivity can be predicted within millisecond response time without any code conversion.

Disclosed is a semiconductor device comprising a substrate including a first surface and a second surface that are opposite to each other, a via structure that penetrates the substrate, a first passivation pattern disposed on the first surface of the substrate and extending onto an upper sidewall of the via structure, and a second passivation pattern disposed on the first passivation pattern and exposing an uppermost surface of the first passivation pattern. At least a portion of the second passivation pattern is externally exposed. The first passivation pattern includes at least one selected from oxide and silicon oxide. The second passivation pattern includes at least one selected from nitride and silicon nitride.

The invention relates to a quartz crucible coating and a preparation method thereof.The coating is of a double-layer composite structure and comprises a substrate layer and a functional layer, the substrate layer is composed of 40-65 vol% of polycrystalline silicon powder (the particle size D50 ranges from 1 micrometer to 5 micrometers) and 35-60 vol% of nanometer silica sol, and the functional layer covers the surface of the substrate layer and is composed of 50-70 vol% of polycrystalline silicon powder, 20-35 vol% of nanometer silica sol and 5-15 vol% of calcium fluoride powder (the particle size D90 is smaller than 0.5 micrometer). The preparation method comprises the following steps: preparing a substrate layer slurry and a functional layer slurry, sequentially coating the inner wall of a crucible with the slurry, drying, and sintering in an inert atmosphere according to a three-step temperature control program to finally form a coating with the thickness of 180-300 microns and the porosity of 8-15 vol%; the coating structure can avoid pollution of silicon nitride or silicon carbide particles, has excellent demolding performance, thermal stability and adhesive force, further improves the service life of a crucible and the purity of a silicon ingot, and meets the requirements of an advanced semiconductor process for cleanliness and reliability.

The present invention relates to a method for controlling physical properties of a silicon nitride substrate, and more specifically, the method comprises the steps of: producing a silicon nitride substrate; and adjusting a residual magnesium content in the silicon nitride substrate. The thermal conductivity of the silicon nitride substrate is inversely proportional to the residual magnesium content in the silicon nitride substrate, and the flexural strength of the silicon nitride substrate is proportional to the residual magnesium content in the silicon nitride substrate.

The invention provides silicon nitride and aluminum nitride powder and a preparation method, and relates to the technical field of ceramic powder. The preparation method of the silicon nitride and aluminum nitride powder comprises the following steps: mixing aluminum powder and aluminum nitride raw powder to obtain a first mixture; mixing silicon powder, silicon nitride raw powder and ammonium salt to obtain a second mixture; paving the first mixture and the second mixture in a material frame padded with a carbon felt, and separating the first mixture from the second mixture by using the carbon felt; the material frame is placed in a self-propagating reaction kettle, nitrogen is introduced after vacuumizing, and the first mixture is ignited so as to induce a combustion synthesis reaction of the second mixture; and after the combustion synthesis reaction, cooling to room temperature, releasing the pressure in the self-propagating reaction kettle, taking out a synthetic product, and grinding the synthetic product to obtain silicon nitride powder and aluminum nitride powder. The purity of the powder material can be improved.

The invention relates to the technical field of optical switches, in particular to a large-scale high-power high-speed optical switch based on a silicon-on-silicon nitride platform, which comprises a first silicon nitride waveguide, a second silicon nitride waveguide, a first optical path distribution unit and a second optical path distribution unit, the first optical path distribution unit is used for correspondingly distributing a first input optical signal into N paths of first output optical signals; the second silicon nitride waveguide is correspondingly provided with N paths of input ports; the first ends and the second ends of the N silicon waveguides are respectively connected with the output port of the first silicon nitride waveguide and the input port of the second silicon nitride waveguide; a first conversion area and a second conversion area are arranged at the joint of the silicon waveguide and the first silicon nitride waveguide and the joint of the silicon waveguide and the second silicon nitride waveguide respectively, and the corresponding conversion areas are used for achieving conversion transmission of optical signals on different waveguides. The problem that an existing optical switch is difficult to bear high power is solved.

The invention relates to a thin film electro-optical crystal-silicon nitride heterogeneous integrated N * N high-speed optical switch array and a preparation method thereof. The thin film electro-optical crystal-silicon nitride heterogeneous integrated N * N high-speed optical switch array is formed by connecting 1 * 2 or 2 * 2 Mach-Zehnder high-speed optical switch units according to a certain topological structure. Wherein the high-speed optical switch unit is composed of a silicon nitride passive waveguide and a thin-film electro-optical crystal / silicon nitride heterogeneous integrated phase shift region. Comprising but not limited to thin-film lithium niobate, thin-film lithium tantalate, barium titanate and lead zirconate titanate is integrated above the silicon nitride phase shifting arm through a micro transfer printing method to form a heterogeneous integrated phase shifting region. The large-scale high-speed optical switch array with excellent performance is realized by combining the characteristics of ultra-low loss, CMOS compatibility, thermal stability and the like of a silicon nitride material, the characteristics of low power consumption, low loss, high-speed modulation and the like of a thin film electro-optical crystal and the advantages of high flexibility, parallel integration, low cost, low loss and the like of a micro transfer printing method.

The invention belongs to the technical field of nanofiltration, and provides a preparation method of a recrystallized silicon carbide-silicon carbonitride ceramic membrane. The preparation method comprises the following steps: applying a polysilazane solution to a porous substrate for the first time, and then performing first pyrolysis to obtain a pyrolysis material; and applying a polysilazane solution on the pyrolysis material for the second time, and then carrying out second pyrolysis to obtain the recrystallized silicon carbide-silicon carbonitride ceramic membrane. According to the invention, a solution containing propargyl polysilazane or organic polysilazane Durazane 1500 quick-drying resin is used as a precursor to prepare the ceramic membrane, and the ceramic membrane has the advantages of high ceramic yield, excellent high-temperature stability, high retention rate and controllable microstructure, and is suitable for separation and protection application in extreme environments.

The invention provides a surface-emitting gallium nitride VCSEL laser chip and an epitaxial defect suppression preparation method thereof, and relates to the technical field of laser chips, the surface-emitting gallium nitride VCSEL laser chip comprises a substrate, a low-temperature nucleating layer, a high-temperature recovery layer, a stress regulation type nano mask composite defect blocking layer, an n-type nitride DBR reflector, an active region, a polarization enhanced tunnel junction and the like, the defect blocking layer adopts an in-situ silicon nitride nano-porous mask layer to be matched with an aluminum gallium nitride / gallium nitride stress compensation superlattice layer, through pulse type lateral epitaxial overgrowth annihilation penetrating dislocation, and the n-type nitride DBR reflector adopts an AlInN / GaN lattice matching material system to be combined with a hydrogen etching interruption modification technology, so that thick film growth with zero cracks and high reflectivity is realized; a polarization enhanced tunneling junction is used at the top to replace ITO, and the hole tunneling probability is enhanced by piezoelectric polarization in InGaN, so that efficient current injection with low working voltage and no absorption loss is realized, the dislocation density and the device voltage are remarkably reduced, and the yield of an epitaxial wafer and the photoelectric conversion efficiency are improved.

The invention discloses a preparation method of stable spray granulation silicon nitride slurry and granulation powder, and belongs to the technical field of ceramic materials. According to the invention, absolute ethyl alcohol is adopted as a solvent, so that the problem that silicon nitride slurry is easy to hydrolyze is solved, and the temperature during spray granulation is reduced. On the basis that a dispersing agent is added into slurry, tetramethylammonium hydroxide is added into the slurry, the Zeta potential value of the slurry is increased, the slurry is made to be in an alkaline environment, dissociation of Si-OH groups is promoted, more negative charges are carried on the surface of silicon nitride, meanwhile, zwitterions released by the tetramethylammonium hydroxide form a double-electron layer around silicon nitride particles, and therefore the conductivity of the silicon nitride particles is improved. The dispersity of the particles in the slurry is improved. The silicon nitride powder is more uniformly distributed in a medium such as a binder due to the improvement of the dispersibility, and the silicon nitride slurry with low viscosity, good dispersibility, good stability and good fluidity can be prepared. The slurry can be more symmetrically gathered and formed in the spray granulation process, and the sphericity degree and apparent density of granulation powder are improved.

The invention relates to the technical field of optical switches, in particular to a high-speed optical switch, which is characterized by comprising a first silicon nitride waveguide, the first silicon nitride waveguide is also provided with a first optical path distribution unit, and the first optical path distribution unit is used for correspondingly distributing a first input optical signal into corresponding N paths of first output optical signals; the first end and the second end of the silicon waveguide are respectively connected with the first silicon nitride waveguide and the second silicon nitride waveguide; the silicon waveguide is connected with a branch waveguide, and the branch waveguide is used for separating a branch optical signal with a specific proportion from a first output optical signal transmitted in the silicon waveguide; and an optical power detection unit is arranged on the branch waveguide. The problem that the optical signal of the existing optical switch is difficult to correct online is solved.

The invention relates to the technical field of cable manufacturing, and discloses a heat preservation frost crack prevention cable which comprises a conductor, an insulating layer and a double-layer co-extrusion functional sheath wrapping the outer side of the insulating layer, and the sheath is composed of a cold-resistant stable layer and a water stop gate layer which are arranged in sequence; nano silicon nitride dispersion liquid is added into the cold-resistant stable layer, polytetrafluoroethylene micro-powder is added into the water stop gate layer, and the nano silicon nitride dispersion liquid and the polytetrafluoroethylene micro-powder form a double protection system of physical blocking and structural supporting, so that interlayer bonding force is strengthened, interlayer gaps are reduced, and a moisture invasion path is blocked. The preparation method comprises the steps of raw material pretreatment, conductor cleaning and drying, insulating layer extrusion, plasma activation, double-layer co-extrusion and finished product drying. The cable solves the problem that a multi-layer sheath of an existing cable is prone to frost heaving cracking due to water infiltration, the frost heaving damage resistance is remarkably improved, the cable is suitable for the high-cold and high-humidity environment, and stable power transmission is guaranteed.

A gas turbine engine component, comprises a densified three-dimensional woven ceramic matrix composite comprising the shape of the gas turbine engine component, the densified three-dimensional woven ceramic matrix composite further comprises a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a Si3N4-BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

The invention provides a high-precision flow control system and a high-precision flow control method aiming at the gas flow control problem of silicon nitride film deposition in a semiconductor manufacturing process. In terms of the system, three gas inlet pipes convey different gases, and the explosion risk is reduced through graded mixing of a three-way pipe; the T-shaped design of the second three-way pipe utilizes gravity to assist mixing; each air inlet pipe is provided with a valve and a sensor to provide comprehensive data support; the mixer is specially designed to fully mix gas; a specific gas flow gradient is matched with a multi-stage mixing process to realize accurate control of a stoichiometric ratio; and high-precision data is provided by a specific angle of the laser detector and an advanced detection technology. The method comprises the steps of gas pipeline distribution conveying and premixing, multi-parameter fusion measurement, self-adaptive control, dynamic calibration, mixer optimization and output and the like. The silicon nitride thin film deposition quality is improved, the system safety and the flow control precision are improved, and the production cost and the safety risk are reduced.

To provide a technology capable of reducing the occurrence of seams when filling a recessed portion with a silicon nitride film.SOLUTION: A film formation method according to an embodiment of the present disclosure includes the steps of (a) preparing a substrate having a recess on its surface, (b) forming a silicon nitride film in the recess, (c) forming an amorphous silicon film in the recess, (d) removing the amorphous silicon film, and (e) filling the recess with a silicon nitride film after step (d), and the amorphous silicon film is formed to have a lower step coverage than the silicon nitride film, and step (c) is performed one or more times during step (b).SELECTED DRAWING: Figure 10

The invention relates to the technical field of spot-size converters, and discloses a lithium niobate film spot-size converter with an asymmetric trident structure and a preparation method of the lithium niobate film spot-size converter with the asymmetric trident structure. The lithium niobate film waveguide layer is positioned on the insulating layer; the silicon dioxide layer is coated on the lithium niobate film waveguide layer; the silicon nitride waveguide layer is located on the silicon dioxide layer; the silicon nitride waveguide layer comprises a first waveguide part, a second waveguide part and a third waveguide part which are connected in sequence in the direction from the input end to the output end of the lithium niobate film spot size converter, and the first waveguide part, the second waveguide part and the third waveguide part are located on the same plane; in the light wave transmission direction, the transverse size of the second waveguide part is sequentially increased, and the transverse size of the third waveguide part is sequentially reduced; according to the invention, the process preparation difficulty is low, high-efficiency coupling with the coupling efficiency of more than 90% from the silicon nitride waveguide to the lithium niobate waveguide can be realized, and the optical fiber coupling alignment tolerance and overlay tolerance as well as the overall coupling efficiency of the spot size converter are improved.

To have excellent surface workability, and to suppress the difference in workability between a surface and an inside, and processing quality and dimensional variations during mass production processing.SOLUTION: Silicon nitride sintered body has a silicon nitride crystal particle and a grain boundary phase, and when a width is D before the surface processing is performed, a relationship between an average particle diameter dA and an average aspect ratio rA of the silicon nitride crystal particles in a first region from the outermost surface to a depth of 0 to 0.01D, and an average particle diameter dB and an average aspect ratio rB of the silicon nitride crystal particles in a second region inside the first region, are satisfied the following formulas. 0.8≤dA / dB≤1.2, 0.8≤rA / rB≤1.2.SELECTED DRAWING: Figure 1

The utility model is applicable to the technical field of silicon nitride ceramic substrate preparation, and provides a surfactant mixing and ball-milling device for silicon nitride ceramic substrate preparation, which comprises a ball mill, a feeding component and a driving component, the ball mill comprises a support arranged horizontally, a hollow circular ball milling barrel and a machine cover arranged in the horizontal direction. The feeding assembly is arranged at the top of the ball milling barrel and is used for injecting milling balls and grinding materials into the ball mill; the driving assembly is arranged at the end, away from the ball milling barrel, of the support and used for providing power for ball milling of the ball mill. The device solves the problems that when powder of a silicon nitride ceramic substrate is prepared in a ball milling mode, a ball mill is prone to being damaged due to the fact that the falling speed of grinding media (steel balls and ceramic balls) is too high, and powder is prone to being splashed due to the fact that the grinding media fall to hit the powder. The purpose of ensuring that the powder and the grinding medium smoothly enter the ball mill through the feeding assembly is achieved.

The present: invention addresses the problem of providing a silicon nitride etching liquid composition which is capable of selectively etching Si3N4 with a practical etching selectivity with respect to SiO2, while suppressing regrowth of SiO2, and which is also capable of suppressing pattern collapse of an SiO2 film in the production of a 3D nonvolatile memory cell. A silicon nitride etching liquid composition for producing a 3D nonvolatile memory cell, which contains phosphoric acid, one or more silane coupling agents and water, but which does not contain ammonium ions.