In Pulsed Laser Deposition (PLD) technique, a high powered laser beam is focused inside a vacuum chamber. The material that needs to be deposited is kept inside the chamber and the process is also known as Physical Vapor Deposition (PVD). To melt, evaporate, and ionize material from the surface of a target, high power laser pulse is used. The technique is best used to deposit high-quality films of materials. In the presence of a background gases like oxygen, this process is incorporated.
The technique is found much better than thin film deposition method. Listed below are the characteristics of PLD technique –
It enables the stoichiometric transfer of materials from target to substrate.The chemical composition of a complex material like YBCO is reproduced in the deposited film.The technique enables high deposition rates and the thickness can be enabled by simply turning on or off the laser.
- The laser is used as an external energy source resulting in a clean process without filaments.
- It occurs in both inert and reactive ground gases.
- The process enables multilayer films to be deposited without the requirement.
High film quality can be achieved with cost effective measures while choosing the conceptual phase of a coating system. The specifications for a thin-film coating should be best known for the overall requirement for a vacuum deposition system.
Here are some suggestions for high-quality deposition system–
First, select the proper substrate size for the tool- The largest part of the cost in a deposition system is the maximum dimension of the substrate. Choose the smallest substrate size to minimize the system cost. It requires larger vacuum chambers along the large pumps and gate valves.
Make sure that all the aspects of the deposition process are considered- Multiple monitoring devices are required within the chamber for complex coating. To evaluate the cost of a system, up-front planning becomes an important part.
Prepare and plan the facilities and the lab- Be ready for the system arrival and make advance planning for various system installations.
Define the required throughput- The addition of a loadlock to an R&D tool can double the throughput for an incremental cost. Minimize the risks by having an entire production line down the line while replacing a key part.
The process of PLD is generally divided into different parts as–
• Laser absorption on the target surface
• Creation of plasma and laser ablation of the target material
• On the substrate, deposition of ablation material
• Dynamics of the plasma
• Nucleation of the film on the substrate surface
The high luminosity and transient nature of the plumes enable the temporary evolution of densities, temperatures, and velocities within the plasma. Different techniques used in the investigation of different stages of creation & creation are – Interferometry, Optical Spectroscopy and Laser-Induced Fluorescence (LIF). In the initial stages of the expansion, the plume emits high intensity broadband emission for saturating the detector.
