A complete project on Preparation of Thin Film by Physical Vapor Deposition (Magnetron Sputtering) Technique is available for study and download.Key features of the project are: Thin Film Technology, Thin Film Deposition, Sputtering, Vacuum System, Magnetron Sputtering, Physical Vapor Deposition. Applications of Thin Film and Sputter Deposition Techniques.
Overview of Preparation of Thin Film by Physical Vapor Deposition Project:
Now a day, technology is the necessity of our life and to fulfill our necessity there is the need of suitable materials and processing techniques. Thin films play the major role in gratifying our need. Modern thin film, technology has evolved into a sophisticated set of techniques used to increase performance and aesthetic value of many products and devices. Thin films are crystalline or non-crystalline materials developed two dimensionally on a substrate’s surface by physical or chemical methods. They play vital role in nearly all electronic and optical devices. The coating of thin metallic film on glass or plastic was among the first one to be founded for optical purposes.
Thin Film Deposition Techniques
Thin film properties are strongly dependent on the method of deposition, the substrate materials, temperature, rate of deposition and composition . There are two methods for the preparation of thin film:
⦁ Chemical vapor deposition (CVD)
⦁ Physical vapor deposition (PVD)
Vapor deposition technique describes any process in which a solid immersed in a vapor becomes larger in mass due to transference of material from the vapor onto the solid surface. The deposition is normally carried out in a vacuum chamber to enable control of the vapor composition. If the vapor is created by physical means without a chemical reaction, the process is classified as physical vapor deposition (PVD), if the material deposited is the product of a chemical reaction; the process is classified as chemical vapor deposition (CVD).
Physical Vapor Deposition
Physical evaporation is one of the oldest methods of depositing metal films. The deposition takes place under vacuum or very carefully controlled atmosphere. Physical vapor deposition is a technique whereby physical process, such as evaporation,sublimation t on a target, facilitates the transfer of atoms from a solid or molten source onto a substrate. Evaporation and sputtering are the most widely used PVD methods for depositing films . Typically, PVD processes are used to deposit films with thicknesses in the range of a few nanometers to thousand of nanometers; however, they can also be used to form multilayer coatings graded composition deposits, very thick deposits and freestanding structures. The substrates can range in size from very small to very large such as the 10′ × 12′ glass panels used for architectural glass. The substrates can range in shape from flat to complex geometries such as watchbands and tool bits. Typical PVD
deposition rates are 10-100Å (1-10 nanometers) per second . PVD processes can be used to deposit films of elements and alloys as well as compounds using reactive.
Construction of Vacuum System
The block diagram of vacuum system is shown in fig 3.8 which shows that a typical system is composed of three major parts connected to each other by valves which keep them isolated. A high vacuum is achieved through the use of two pumps, a rotary or mechanical pump and an oil vapor diffusion pump. The diffusion pump cannot discharge directly to atmosphere, and so the rotator/mechanical pump is used in order to rough the chamber to below about 0.1Torr in order that diffusion pump is not subjected to a large load. There is a gas cylinder containing Argon gas which is connecting to the chamber by leak valve, allowing control of gas floe rate. Pressure is monitored by the use of various gauges. Pirani pressure gauge is use to monitor the pressure in the chamber and at the back of diffusion pump and penning gauges are used to measure accurately the pressure in both chamber and reservoir.
Another technique by which the deposition rate achieved over that of the simple diode sputtering process may be increased is through the use of magnetic fields to constrain the plasma close to the sputter target. Magnets situated beside or underneath the target of a diode sputtering source can be used to constrain the electrons emitted from the cathode to orbit in close proximity of the cathode. The probability that such an orbiting electron will strike a process gas molecule, causing ionization, is greatly increased without the need to increase process gas pressure. The complete apparatus of magnetron sputtering is shown in figure1.7.