Hafnium Oxide

Hafnium oxide sputtering target is a physical vapour deposition (PVD) process, high purity hafnium oxide as raw material, can be made in a variety of vacuum coating scenarios by sputtering hafnium oxide deposited on the substrate to form a thin film of the key materials in semiconductors, optics, electronics and many other high-tech fields have a wide range of applications.

Characteristics

Purity: High purity is generally required, usually 99.9% or higher, and even 99.99% or higher. High purity can reduce the impact of impurities on the performance of sputtered films, ensuring the quality and stability of the film.

Density: The theoretical density of hafnium oxide is approximately 9.68 grams per cubic centimetre, but the actual density of sputtering targets varies depending on factors such as manufacturing process and porosity. High-quality sputtering targets should have a high relative density, generally above 90%, or even close to the theoretical density, so as to ensure the uniformity and stability of the material during the sputtering process.

Hardness: Hafnium oxide has a high hardness, around 6.5 on the Mohs hardness scale, which enables the sputtering target to withstand high energy impacts and abrasion during the sputtering process and to have a long service life.

Thermal conductivity: Thermal conductivity is the ability of a material to conduct heat. Hafnium oxide has a relatively low thermal conductivity of about 3-5 watts per metre Kelvin. This means that heat generated on the surface of the target during the sputtering process is not easily and quickly transferred, which can lead to an increase in the surface temperature of the target and the need for appropriate cooling measures in the sputtering equipment.

Melting point: Hafnium oxide has a high melting point of approximately 2758°C. The high melting point ensures that the target can be sputtered at high temperatures. The high melting point ensures that the target can withstand high energy inputs during the sputtering process without melting or deforming, which is conducive to stable sputter coating.

Grain size: Grain size has an important influence on the performance of sputtering targets. Smaller grain size can improve the strength and toughness of the target, but also helps to improve the uniformity and densification of the sputtered film. In general, hafnium oxide sputtering targets have grain sizes in the micron range, such as 1-10 microns.

Crystal structure: Hafnium oxide has a variety of crystal structures, such as monoclinic, tetragonal and cubic phases. The different crystal structures affect the physical and chemical properties of the sputtering target, as well as the properties of the sputtered film. In practice, it is necessary to choose the appropriate crystal structure according to the specific needs.

Sputtering rate: The sputtering rate is the speed at which the material on the surface of the target is sputtered and deposited onto the substrate during the sputtering process. The sputtering rate of a hafnium oxide sputtering target is affected by a number of factors, such as sputtering power, gas pressure, and the distance between the target and the substrate. In general, under the right sputtering conditions, the sputtering rate of hafnium oxide is relatively stable and can meet the requirements of different application scenarios on the speed of film deposition.

Film quality: The films sputtered by hafnium oxide sputtering targets have good quality, such as high purity, uniformity, densification and good adhesion. These properties make hafnium oxide thin films have a wide range of applications in semiconductor, optical, electronic and other fields.

Stress properties: Stresses are generated in the thin films during the sputtering process. Hafnium oxide sputtered films usually have a certain amount of stress, the size and nature of the stress will be affected by sputtering process parameters, film thickness, substrate materials and other factors. In practice, the stress in the film needs to be controlled to ensure the quality and stability of the film.

Applications

Semiconductor field:

Preparation of high-performance capacitors and optoelectronic components: hafnium oxide has a high dielectric constant, higher degree of polarisation and better insulating properties under the same electric field, which can be used to manufacture high-performance capacitors and improve the capacitor’s energy storage capacity; in optoelectronic components, the use of its good electrical properties, which helps to increase the efficiency of photoelectric conversion and the speed of signal transmission.

Production of field effect transistors: its high breakdown electric field characteristics make it less likely to breakdown under the same electric field, with good voltage resistance, can be used in the preparation of high-performance field effect transistors, such as metal-oxide-semiconductor field effect transistors (MOSFETs), etc., to improve the switching speed and stability of the transistor.

Preparation of gate oxides in integrated circuits: In advanced integrated circuit processes, such as complementary metal oxide semiconductor technology (CMOS), hafnium oxide sputtering targets can be used to prepare gate oxides. It has the advantages of high reliability, low leakage current, high carrier mobility, etc. It can meet the high-performance requirements of integrated circuits for gate oxides, and help to improve the integration and performance of chips.

Optical field:

Optical film coatings: Hafnium oxide optical films have high refractive index, low loss and good thermal stability, and can be used to prepare high-performance optical coatings. For example, in the optical fibre coating, it can improve the transmission efficiency of light; in the preparation of optical lenses and mirrors, it can reduce the loss of the optical system and improve the imaging quality.

Laser Optical Components: It is used in the manufacture of laser optical components, such as laser mirrors and laser windows. Its good optical performance and thermal stability can withstand the high energy radiation of laser to ensure the normal operation of laser optical system.

Superconducting materials field: it can be used to prepare high-temperature superconducting materials, such as hafnium – barium – copper – oxygen (Hf-Ba-Cu-O, HBC) system and hafnium – lanthanum – aluminium – oxygen system. These high-temperature superconductors have high critical temperatures and can work in the temperature region of liquid nitrogen, and have a wide range of applications in fields such as magnetic levitation trains, high-performance computers, and magnetic resonance imaging.

Other fields:

Wear-resistant coating: using its high hardness and good wear resistance, the coating can be prepared on the surface of some parts that need to be wear-resistant, such as mechanical parts, cutting tools, etc., which can improve the wear resistance and service life of the parts.

Decorative coatings: coatings with special optical effect or texture can be prepared on the surface of some decorative or high-grade products to increase the aesthetics and added value of the products.