Physical Vapor Deposition (PVD):
           PVD encompasses a group of vacuum techniques used for depositing 
                                     . 
    thin  films  of  different  materials  onto  various  substrates  by  physical 
    means.  process  is  a  dry  vacuum  deposition  method  to  coat  an  entire 
    object (or substrate) at once. The PVD reactive processes are a common 
    method for depositing a hard coating of metal. They combine an active 
    gas, such as nitrogen, oxygen, or methane with the plasma bombardment 
    of the substrate. The main difference of PVD methods is the way they 
    produce the metal vapor and the plasma. 
                                      
    In general, it can be categorized into the following groups:
    1- Mechanical 
    2- Evaporation
    3-  Sputtering
    4- Ion plating
    5- Pulse laser ( PLD and PLA)
   1- Mechanical (milling) method
 • This method produces mechanical Nano-materials 
  in powder form, where material is placed under a 
  very high energy and milling by balls made of 
  stainless . can be made Powder up in size from 3-
  25 (nanometer).
            2- Evaporation
                            Evaporation
                            Evaporation
           Thermal 
           Thermal                 E-beam 
                                   E-beam                MBE
          evaporation                                    MBE
          evaporation            e  vaporation
                                 e  vaporation
           
   Evaporation: is one of the most common methods of thin film deposition. 
  Although it is one of the oldest physical techniques, it is still widely used in 
  the laboratory and in industry. In this process, a vapor is generated by 
  evaporating or subliming a source material, which is subsequently 
  condensed as a solid film on a substrate. 
   
  2.1. Thermal evaporation
   In thermal evaporation, the target material is melted and evaporated or 
  sublimed using an electric resistance heater. In this process, the vapor 
  pressure in the chamber (Figure bellow) is raised from the initially very low 
  pressure to one that allows the material to be deposited on the substrate. 
  This initial high vacuum is necessary because it allows the vapor to reach 
  the substrate without reacting with or scattering by other atoms in the 
  chamber.
  The deposition system consists of: 
  1. nozzle sprayer with (0.1-0.8)mm inner diameter and 
  inlet for carrier gas (N2). 
  2. Heater (hot plate), for heating substrate. It is used 
  for controlling the temperature of the substrate in 
  which the film deposit on it 
  3. Temperature controller. 
  It is use for measuring the temperature of heater and 
  substrate .It connected with a digital counter to 
  measure the temperature.
  4. Chamber with ventilator. 
  5. Air compressor or gas propellant.