Advantages of Silicon Nitride Substrat

Silicon nitride substrate is one of the most popular ceramic materials in the power electronic industry. It offers high thermal conductivity, excellent bending strength and fracture toughness.The present invention describes a manufacturing method of a silicon nitride substrate as an insulating ceramic substrate used in a power semiconductor module. The manufacturing method includes setting a silicon nitride powder having an oxygen amount of 2.0 mass% or less and a specific surface area of 3 to 11 m2/g as a raw material, adding a sintering additive powder in an amount of 4 to 15 mol%, and mixing these materials using an organic solvent that has a water content ratio of 0.03 to 3 mass% to obtain a slurry.

Thermal Conductivity

Thermal conductivity is an important property of ceramic substrates. These materials are used as the substrates of power electronic devices because they dissipate heat and provide mechanical strength, both of which are essential for these types of devices to operate properly.The thermal conductivity of silicon nitride ceramics depends on several factors, including the oxygen content of the crystal lattice and the grain boundary phase. It is also affected by the sintering agent used during the sintering process. The thermal conductivity of a silicon nitride substrate can be improved by using rare-earth oxide additives. These oxide additives, such as Yb2O3, Nb2O5, and Cd2O5, can be added to the sintering agent to improve its properties.Yb2O3 can enhance the thermal conductivity of a silicon nitride ceramic by forming an oxygen-rich layer on the surface. However, Yb2O3 is also toxic and requires special treatment to avoid contamination.Therefore, an alternative approach to improve the thermal conductivity of a silicon based ceramic substrate is to use a non-oxide additive. In this study, Nb was added to the Si3N4 substrates in order to increase the thermal conductivity of these samples. The results showed that the thermal conductivity of these substrates was significantly increased when Nb was added.Another promising nitride substrate material is g-Si3N4 and g-Ge3N4. These nitrides have high RT k and are predicted to exhibit isotropy in the thermal expansion and thermal conductivity endowed by their structure symmetry. These properties are expected to make g-Si3N4 and its derivatives attractive substrate materials for power electronic devices by reducing the thermal stress and cracking during service.A combination of density functional theory and a modified Debye-Callaway model was applied to predict the thermal conductivity of these two nitrides. These results show that g-Si3N4 and the derivative g-Ge3N4 have a high RT k of over 250 Wm-1K-1 for samples with grain size of 100 mm. This thermal conductivity is achieved by relatively small anharmonicity, large acoustic phonon velocities and Debye temperatures.As a result, the thermal conductivity of g-Si3N4 and of its derivative g-Ge3N4 increases as the temperature increases. This is because g-Si3N4 and related compounds have a larger acoustic phonon MFP than b-Si3N45. This causes the phonons to be annihilated from the grain boundaries with greater intensity.

Mechanical Properties

Silicon nitride substrate is one of the most promising materials for semiconductor devices because of its good thermal conductivity and mechanical properties. Its high melting point, hardness, wear resistance, oxidation resistance and other advantages make it suitable for the application of power semiconductor devices in electric vehicles and solar photovoltaic power generation, among others.The use of silicon nitride in power semiconductors has increased rapidly, particularly for the development of IGBTs. In these devices, the heat generated by the semiconductors needs to be released, so insulating substrates with high thermal conductivity are of great importance. The application of a silicon nitride substrate has also been increasing in the field of power control systems for solar and wind energy generations.In this paper, we studied the effect of silane flow rate on atomic percentage, atomic ratio, and elastic modulus of crystalline SiNx films. We found that the N:Si atomic ratio decreased by a factor of about 1.33 with the increase of silane flow rate, while the elastic modulus increased slightly. These results suggest that the N:Si atomic ratio was controlled by the Si-N bonding in the crystalline films.We also analyzed the effect of non-oxide additives on the thermal and electrical properties of sintered silicon nitride. The XPS method was applied to identify the oxidation of these additives and the effects on the thermal and electrical properties of nitride films.Moreover, we compared the performance of various nitride films with that of conventional sintered stoichiometric Si3N4 and SiOxNy nitride substrates. The results show that the nitride films with a lower atomic ratio have better mechanical properties. The bending strength and fracture toughness of the nitride films were comparable to those of the conventional stoichiometric Si3N4 substrate.We fabricated the Si3N4 substrate by press molding, doctor blade molding, and extrusion molding as shown in Figure 3. The silicon nitride substrates were sintered in a flowing nitrogen atmosphere at 1900 oC for 5 hours under a uniaxial pressure of 30 MPa. After sintering, the substrates were cut into plate type and bar type specimen for further characterization.

Electrical Properties

Silicon nitride substrate is a good choice for power semiconductors due to its excellent thermal conductivity and mechanical properties. It can also withstand high temperature, strong stress and oxidation. In addition, it is compatible with a variety of environments. Therefore, it can be used in a wide range of applications, including solar photovoltaics and electric vehicles.Nitride films on silicon wafers are a popular alternative to aluminum oxide and AlN ceramic because of their increased thermal conductivity, RF power density, and passivation properties. These films are also suitable for integrating into high-performance devices, such as solar cells and LEDs. However, they are often not as transparent as amorphous silicon nitride (a-SiNx) and require careful deposition.The refractive index (RI) of nitride films on silicon is influenced by the ratio of silane to ammonia precursor gases. The higher the RI, the better the surface passivation properties. Moreover, the rf power density of silicon nitride films is also affected by the deposition temperature.As a result, it is important to understand the effect of temperature on nitride film RI. A high-temperature nitride film will thin faster and grow thicker, while a low-temperature nitride film grows slower and thinner. This is because the temperature changes the crystallographic structure of nitride particles.Several methods are available to measure the electrical resistivity of nitride films on silicon. These methods include scanning electron microscopy, energy dispersive x-ray spectroscopy, and a high-resistance meter. These measures are useful for determining the nitride film’s refractive index.These results show that a nitride film on a silicon substrate can have a refractive index of 1.2 to 1.33 at 950degC. This is a significant improvement over the refractive index of the same material deposited at 400degC, which is the typical thermal annealing temperature for silicon.Furthermore, the nitride film’s rf power density increases with increasing temperature. Ultimately, the refractive index of nitride films on silicon can be tailored to suit individual device needs.Several factors can affect the nitride film’s electrical properties, such as the type of gas precursors, the pressure and temperature conditions during the deposition process, the amount of nitride present in the substrate, and the nitride thickness. Nevertheless, the electrical properties of nitride films on silicon are generally comparable to those of amorphous silicon nitride.

Chemical Properties

The chemical properties of a material describe the changes it undergoes or can cause. This is different from the physical properties of a material, which include its shape (volume and size), color, texture, flexibility, density, and mass. These are a result of its molecular structure.A chemical property of a substance is the ability for it to change its molecular structure or react with other materials. Examples of these include flammability, toxicity, acidity, reactivity, heat of combustion, and chemical stability.In the case of a silicon nitride substrate, these properties are important in understanding its behavior as a surface layer. These properties can also influence the way the nitride film reacts with light and affect its refractive index.Nitride based materials have a number of benefits that make them desirable for many applications. For example, they are resistant to oxidation and corrosion, and can be used for applications that require high thermal conductivity. They also have a low melting point, which can help prevent molten nitride from damaging a chip’s circuitry.However, a significant problem with these materials is that they can shrink during the densification process, which can cause problems with production. For example, if a molding crack occurs during the forming process, it can damage the silicon nitride substrate and lead to manufacturing costs that are higher than expected.These problems can be solved with a process called “nitride re-machining.” This process involves abrading a surface with a diamond tool. The tool is designed to gradually abrade the material until it is denser and smoother than before.In addition, a nitride re-machining process can also reduce the cost of manufacturing the substrate. This process allows the manufacturer to reuse a portion of the substrate, which saves money and reduces waste.The nitride re-machining of the silicon nitride substrate helps to improve the material’s thermal conductivity, which makes it ideal for power applications. Because of this, it is one of the most popular substrates in use for power devices.Nitride based materials are also able to resist a wide range of temperatures, which is beneficial for the development of high-speed semiconductors. This allows them to be used in a variety of applications, such as the thick-film EL panels in LCD vehicle displays.