Lab Materials

In the field of high purity materials, purity levels are expressed as percentages, such as 2N for 99%, 2N5 for 99.5%, 3N for 99.9%, 3N5 for 99.95%, 4N for 99.99%, 4N5 for 99.995%, 6N for 99.9999%, 7N for 99.99999%. For example, 4N-6N implies a purity level ranging from 99.99% to 99.9999%.

About Sputtering

Sputtering is a physical phenomenon where energetic particles from a plasma or gas bombard a solid material's surface, causing microscopic particles to be ejected. This process occurs naturally in outer space and can lead to unwanted wear on precision components. However, it is also utilized in science and industry to perform precise etching, analytical techniques, and deposit thin film layers in the manufacture of optical coatings, semiconductor devices, and nanotechnology products.

Sputtering target application

Sputtering targets have a wide range of applications, including the creation of coatings for various products. For instance, tantalum sputtering targets are used in the production of essential components in modern-day electronics. These components include microchips, memory chips, print heads, and flat panel displays, among others.

Another significant application of sputtering targets is in the production of low-radiation coated glass, also known as Low-E glass. This type of glass is commonly used in building construction due to its energy-saving properties, ability to control light, and aesthetic appeal.

With the growing demand for renewable energy, sputter coating technology is also utilized in the preparation of third-generation thin-film solar cells. These solar cells are prepared using sputtering targets, making it an essential component in the production of solar panels.

FAQ

What is Physical vapor deposition (PVD)?

Physical vapor deposition (PVD) is a technique for depositing thin films by vaporizing a solid material in a vacuum and then depositing it onto a substrate. PVD coatings are highly durable, scratch-resistant, and corrosion-resistant, making them ideal for a variety of applications, from solar cells to semiconductors. PVD also creates thin films that can withstand high temperatures. However, PVD can be costly, and the cost varies depending on the method used. For instance, evaporation is a low-cost PVD method, while ion beam sputtering is rather expensive. Magnetron sputtering, on the other hand, is more expensive but more scalable.

What is sputtering target?

A sputtering target is a material used in the process of sputter deposition, which involves breaking up the target material into tiny particles that form a spray and coat a substrate, such as a silicon wafer. Sputtering targets are typically metallic elements or alloys, although some ceramic targets are available. They come in a variety of sizes and shapes, with some manufacturers creating segmented targets for larger sputtering equipment. Sputtering targets have a wide range of applications in fields such as microelectronics, thin film solar cells, optoelectronics, and decorative coatings due to their ability to deposit thin films with high precision and uniformity.

What are high purity materials?

High purity materials refer to substances that are free from impurities and possess a high level of chemical homogeneity. These materials are essential in various industries, particularly in the field of advanced electronics, where impurities can significantly affect the performance of devices. High purity materials are obtained through various methods, including chemical purification, vapor-phase deposition, and zone refining. In the preparation of electronic grade single crystal diamond, for example, a high-purity raw material gas and an efficient vacuum system are necessary to achieve the desired level of purity and homogeneity.

What is magnetron sputtering?

Magnetron sputtering is a plasma-based coating technique used to produce very dense films with excellent adhesion, making it a versatile method for creating coatings on materials that have high melting points and cannot be evaporated. This method generates a magnetically confined plasma near the surface of a target, where positively charged energetic ions collide with the negatively charged target material, causing atoms to be ejected or "sputtered." These ejected atoms are then deposited on a substrate or wafer to create the desired coating.

How are sputtering targets made?

Sputtering targets are made using a variety of manufacturing processes depending on the properties of the target material and its application. These include vacuum melting and rolling, hot-pressed, special press-sintered process, vacuum hot-pressed, and forged methods. Most sputtering target materials can be fabricated into a wide range of shapes and sizes, with circular or rectangular shapes being the most common. Targets are usually made from metallic elements or alloys, but ceramic targets can also be used. Compound sputtering targets are also available, made from a variety of compounds including oxides, nitrides, borides, sulphides, selenides, tellurides, carbides, crystalline, and composite mixtures.

Why magnetron sputtering?

Magnetron sputtering is preferred due to its ability to achieve high precision in film thickness and density of coatings, surpassing evaporation methods. This technique is especially suitable for creating metallic or insulating coatings with specific optical or electrical properties. Additionally, magnetron sputtering systems can be configured with multiple magnetron sources.

What is sputtering target used for?

Sputtering targets are used in a process called sputtering to deposit thin films of a material onto a substrate using ions to bombard the target. These targets have a wide range of applications in various fields, including microelectronics, thin film solar cells, optoelectronics, and decorative coatings. They allow for the deposition of thin films of materials onto a variety of substrates with high precision and uniformity, making them an ideal tool for producing precision products. Sputtering targets come in various shapes and sizes and can be specialized to meet the specific requirements of the application.

What are the materials used in thin film deposition?

Thin film deposition commonly utilizes metals, oxides, and compounds as materials, each with its unique advantages and disadvantages. Metals are preferred for their durability and ease of deposition but are relatively expensive. Oxides are highly durable, can withstand high temperatures, and can be deposited at low temperatures, but can be brittle and challenging to work with. Compounds offer strength and durability, can be deposited at low temperatures and tailored to exhibit specific properties.

The selection of material for a thin film coating is dependent on the application requirements. Metals are ideal for thermal and electrical conduction, while oxides are effective in offering protection. Compounds can be tailored to suit specific needs. Ultimately, the best material for a particular project will depend on the specific needs of the application.

What are sputtering targets for electronics?

Sputtering targets for electronics are thin discs or sheets of materials such as aluminum, copper, and titanium that are used to deposit thin films onto silicon wafers to create electronic devices like transistors, diodes, and integrated circuits. These targets are used in a process called sputtering, in which atoms of the target material are physically ejected from the surface and deposited onto a substrate by bombarding the target with ions. Sputtering targets for electronics are essential in the production of microelectronics and typically require high precision and uniformity to ensure quality devices.

What are the methods to achieve optimal thin film deposition?

To achieve thin films with desirable properties, high-quality sputtering targets and evaporation materials are essential. The quality of these materials can be influenced by various factors, such as purity, grain size, and surface condition.

The purity of sputtering targets or evaporation materials plays a crucial role, as impurities can cause defects in the resulting thin film. Grain size also affects the quality of the thin film, with larger grains leading to poor film properties. Additionally, the surface condition is crucial, since rough surfaces can result in defects in the film.

To attain the highest quality sputtering targets and evaporation materials, it is crucial to select materials that possess high purity, small grain size, and smooth surfaces.

Uses of Thin Film Deposition

Zinc Oxide-Based Thin Films

ZnO thin films find applications in several industries such as thermal, optical, magnetic, and electrical, but their primary use is in coatings and semiconductor devices.

Thin-Film Resistors

Thin-film resistors are crucial for modern technology and are used in radio receivers, circuit boards, computers, radiofrequency devices, monitors, wireless routers, Bluetooth modules, and cell phone receivers.

Magnetic Thin Films

Magnetic thin films are used in electronics, data storage, radio-frequency identification, microwave devices, displays, circuit boards, and optoelectronics as key components.

Optical Thin Films

Optical coatings and optoelectronics are standard applications of optical thin films. Molecular beam epitaxy can produce optoelectronic thin-film devices (semiconductors), where epitaxial films are deposited one atom at a time onto the substrate.

Polymer Thin Films

Polymer thin films are used in memory chips, solar cells, and electronic devices. Chemical deposition techniques (CVD) offer precise control of polymer film coatings, including conformance and coating thickness.

Thin-Film Batteries

Thin-film batteries power electronic devices such as implantable medical devices, and the lithium-ion battery has advanced significantly thanks to the use of thin films.

Thin-Film Coatings

Thin-film coatings enhance the chemical and mechanical characteristics of target materials in various industries and technological fields. Anti-reflective coatings, anti-ultraviolet or anti-infrared coatings, anti-scratch coatings, and lens polarization are some common examples.

Thin-Film Solar Cells

Thin-film solar cells are essential to the solar energy industry, enabling the production of relatively cheap and clean electricity. Photovoltaic systems and thermal energy are the two main applicable technologies.

What is the lifetime of a sputtering target?

The lifetime of a sputtering target depends on factors such as the material composition, purity, and the specific application it is being used for. Generally, targets can last for several hundred to a few thousand hours of sputtering, but this can vary widely depending on the specific conditions of each run. Proper handling and maintenance can also extend the lifetime of a target. In addition, the use of rotary sputtering targets can increase runtimes and reduce the occurrence of defects, making them a more cost-effective option for high volume processes.

Factors and Parameters that Influence Deposition of Thin Films

Deposition Rate:

The rate at which the film is produced, typically measured in thickness divided by time, is crucial for selecting a technology suitable for the application. Moderate deposition rates are sufficient for thin films, while quick deposition rates are necessary for thick films. It is important to strike a balance between speed and precise film thickness control.

Uniformity:

The consistency of the film across the substrate is known as uniformity, which usually refers to film thickness but can also relate to other properties such as the index of refraction. It is important to have a good understanding of the application to avoid under- or over-specifying uniformity.

Fill Capability:

Fill capability or step coverage refers to how well the deposition process covers the substrate's topography. The deposition method used (e.g., CVD, PVD, IBD, or ALD) has a significant impact on step coverage and fill.

Film Characteristics:

The characteristics of the film depend on the application's requirements, which can be categorized as photonic, optical, electronic, mechanical, or chemical. Most films must meet requirements in more than one category.

Process Temperature:

Film characteristics are significantly affected by process temperature, which may be limited by the application.

Damage:

Each deposition technology has the potential to damage the material being deposited upon, with smaller features being more susceptible to process damage. Pollution, UV radiation, and ion bombardment are among the potential sources of damage. It is crucial to understand the limitations of the materials and tools.

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