Tag: Pulsed laser deposition

Advantages and Disadvantages of Pulsed Laser Deposition (PLD)

Introduction to Pulsed Laser Deposition (PLD)

In the world of materials science, the quest for precision and versatility in thin film preparation has led to the development of several advanced techniques, among which Pulsed Laser Deposition (PLD) stands out.

PLD, also known as Pulsed Laser Ablation, harnesses the power of a laser to bombard the surface of a target material. This process elevates the surface temperature significantly, producing high-temperature and high-pressure plasma (T > 104K). The material then deposits on various substrates to form a thin film. This technique is celebrated for its ability to create films with unparalleled precision, catering to a wide range of applications from microelectronics to optical technologies.

Simplified schematic diagram illustrating the pulsed laser deposition (PLD) set-up.
Simplified schematic diagram illustrating the pulsed laser deposition (PLD) set-up. Ogugua, Simon & Swart, H. & Ntwaeaborwa, Odireleng. (2020). Latest Development on Pulsed Laser Deposited ThinFilms for Advanced Luminescence Applications. Coatings. 10. 1078. 10.3390/coatings10111078.

Advantages of PLD

Multi-component Films

One of the hallmark advantages of PLD is its adeptness at producing multi-component films that maintain the desired stoichiometric ratios with ease. This characteristic is particularly beneficial in applications requiring precise chemical compositions, making PLD a preferred method for developing advanced functional materials.

High Deposition Rate and Flexibility

PLD boasts a high deposition rate, ensuring a swift test period and minimal substrate temperature requirements. This efficiency, coupled with the uniformity of the films prepared, positions PLD as a highly effective method for thin film deposition. Moreover, the process’s inherent simplicity and flexibility signal its vast development potential and compatibility across a broad spectrum of materials science endeavors.

Adjustable Process Parameters

The ability to arbitrarily adjust process parameters is another feather in PLD’s cap. This flexibility allows for the easy preparation of multilayer films and heterojunctions, with no limitation on the type of PLD targets. The adaptability in choosing multi-target components further underscores PLD’s versatility in meeting diverse material preparation needs.

Non-polluting and Easy Control

Utilizing UV pulsed lasers as the energy source for plasma generation, PLD stands out as a non-polluting technique. This aspect, combined with the method’s ease of control, ensures that PLD aligns with the growing demand for environmentally friendly and easily manageable manufacturing processes in the production of thin film materials.

Disadvantages of PLD

Despite its numerous advantages, PLD is not without its challenges. One notable issue is the presence of molten small particles or target fragments in the deposited film, which can significantly compromise the quality of the film. These particles, sputtered during the laser-induced explosion, introduce defects that detract from the film’s integrity.

The feasibility of PLD for large-area deposition also remains unproven, limiting its application in industries requiring expansive film coverage. Coupled with an average deposition rate that is slow relative to other methods, these limitations suggest areas where PLD may benefit from further refinement and innovation.

Moreover, considering the cost and scale of laser film preparation equipment, PLD’s current applicability appears confined to high-tech fields such as microelectronics, sensor technology, optical technology, and new material films. This niche positioning highlights the need for continued development to expand PLD’s utility across a broader range of applications.

Stanford Advanced Materials (SAM) and PLD

In the landscape of thin film preparation, the role of reliable materials suppliers cannot be overstated. Stanford Advanced Materials (SAM) Corporation emerges as a global leader in providing a diverse array of sputtering targets, including metals, alloys, oxides, and ceramic materials. These materials are pivotal for PLD and other thin film deposition techniques, underscoring SAM’s contribution to advancing the frontiers of materials science and engineering.

Conclusion

Pulsed Laser Deposition (PLD) presents a compelling technique in the preparation of thin films, offering a unique blend of precision, versatility, and environmental friendliness. While its advantages pave the way for innovative applications, the method’s limitations highlight areas ripe for research and development. As the field continues to evolve, partnerships with materials suppliers like Stanford Advanced Materials (SAM) will be crucial in harnessing PLD’s full potential, driving forward the technological advancements that rely on high-quality thin films.

Pros & Cons of 4 Film Manufacturing Methods

The properties of the thin film are determined by the manufacturing method, and different methods have their own advantages and disadvantages. Commonly used preparation processes include magnetron sputtering, chemical vapor deposition, vacuum evaporation, pulsed laser deposition, etc. Among them, magnetron sputtering deposition technology has been widely researched and applied due to its high film formation rate and good uniformity.

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Magnetron Sputtering

The basic principle of the method is that under the action of electric and magnetic fields, the accelerated high-energy particles (A, +) bombard the surface of the target, and after the energy is exchanged, the atoms on the surface of the target escape from the original lattice, and finally, the sputtering particles are deposited on the surface of the substrate and react with oxygen atoms to form an oxide film. The magnetron sputtering process is characterized by excellent optical and electrical properties of the film deposited at low temperatures. In addition, it has the advantages of a high deposition rate, low substrate temperature, good film adhesion, easy to control, and large-area film formation. Therefore, it has become the most researched and widely used film-forming technology in industrial production today as well as a research hotspot in ITO film preparation technology.

Chemical Vapor Deposition

The chemical vapor deposition method is a process in which a gaseous reactant (including a gaseous reactant that becomes a vaporized condensed matter after evaporation) is chemically reacted on the surface of the substrate to deposit a film. This chemical reaction occurring on the surface of the substrate is usually the thermal decomposition and in-situ oxidation of the source material. The reaction system selected by the CVD method must satisfy:

(1) At the deposition temperature, the reactant must have a sufficiently high vapor pressure;
(2) The chemical reaction product must be in a gaseous state except for the solid matter deposited on the substrate;
(3) The vapor pressure of the deposit should be low enough to ensure good adsorption on a substrate having a certain temperature.

Vacuum Evaporation

The vacuum evaporation method is a method in which a raw material of a to-be-formed film in an evaporation vessel is vaporized from a surface to form a vapor stream, and is incident on a surface of the substrate to react with a gas to form a film in a vacuum chamber. A high-quality ITO film can be prepared by the electron beam evaporation deposition method, in which the evaporation substance is In2O3 doped with SnO2, and the mass percentage of SnO2 is 10%. Under suitable process conditions, the deposited film has a minimum resistivity of 4×10-4 Ω•cm and an average transmittance in the visible range of more than 90%.

Pulsed Laser Deposition

The pulsed laser deposition (PLD) process is a very competitive new vacuum physical deposition process developed in recent years. Compared with other processes, it has the advantages of precise control of stoichiometry, synthesis, and deposition, and no requirement for the shape and surface quality of the target, so the surface of the solid material can be processed without affecting the material body.

Stanford Advanced Materials(SAM) is a global sputtering targets manufacturer which supplies high-quality and consistent products to meet our customers’ R&D and production needs. Please visit https://www.sputtertargets.net/ for more information.

Working Mechanism of Pulsed Laser Deposition

Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited.  Although the equipment of pulsed laser deposition (PLD) system is simple, its working mechanism is related to many complicated physical phenomena. It includes all physical interactions between the laser and the substance when the high-energy pulsed radiation strikes the solid sputtering target, the formation of plasma plumes and the transfer of the molten material through the plasma plume to the surface of the heated substrate. Therefore, PLD can generally be divided into the following three stages:

Interaction between laser radiation and the sputtering target

In this stage, the laser beam is focused on the surface of the target materials. When sufficient high energy flux and short pulse width are achieved, all elements of the target surface are rapidly heated to the evaporation temperature. At this point, the material in the target will be sputtered from the target. The instantaneous melting rate of the target is highly dependent on the flow of laser light onto the target. The melting mechanism involves many complex physical phenomena such as collisions, heat, excitation with electrons, delamination, and fluid mechanics.

Dynamics of molten matter

In the second stage, according to the law of aerodynamics, the sputtered particles have a tendency to move toward the substrate. The space thickness varies with the function cosn θ, and n>>1. The area of the laser spot and the temperature of the plasma have an important influence on the uniformity of the deposited film. The distance between the target and the substrate is another factor that affects the angular extent of the molten material. It has also been found that placing a baffle close to the substrate narrows the angular extent.

Deposition of molten material on the substrate

The third stage is the key to determining the quality of the film. The high-energy nuclides emitted hit the surface of the substrate and may cause various damages to the substrate. The high energy nuclide sputters some of the atoms on the surface, and a collision zone is established between the incident stream and the sputtered atoms. The film is formed immediately after the formation of this thermal energy zone (collision zone), which is the best place to condense particles. As long as the condensation rate is higher than the release rate of the sputtered particles, the heat balance condition can be quickly reached, and the film can be formed on the surface of the substrate due to the weakened flow of the molten particles.

The original text is from https://samsputtertargets.blogspot.com/.

Please visit https://www.sputtertargets.net/ for more information.