Plasma Application_IIT_Roorkee_lecture.pptx

Plasma Application

1. PHN-317 Plasma Applications- Kuneh Shah Plasma Enhanced Chemical Vapor Deposition Plasma Physics and Its Applications

2. Vapor Deposition Vapor deposition technique is coating processes in which materials in a vapor state are condensed through condensation, chemical reaction, or conversion to deposit thin films on different substrates

3. Physical Vapor Deposition Sputtering Evaporation(Thermal ,Electron Beam, Arc) Every evaporation process of a metal belongs to this type

4. Chemical Vapor Deposition

5. Chemical Vapor Deposition Gaseous precursors react on the substrate to form a solid film High-purity coatings and better step coverage for complex surfaces compared to PVD Highly versatile and applicable to both amorphous and crystalline materials. Formation of soot due to incomplete oxidation of firewood since prehistoric times is probably the oldest example of deposition using CVD.

6. Types of CVD Atmospheric Pressure CVD: Relatively Low Operating Cost But susceptible to oxidation and Contamination Low Pressure CVD: Uniformity and High Purity, 10-1000 Pa Metal Organic CVD : MOCVD precursor are highly volatile at moderate to Low Temperatures. Lower reaction temperature. Laser CVD: Localized heating and deposition Plasma Enhanced CVD

7. Plasma Enhanced CVD Low Temperature (<150 C) CVD process used to deposit thin films due to a chemical reaction(decomposition)of precursor or reactants present in the form of plasma on the surface of the substrate.

8. Plasma Assisted Coating Techniques Development of PECVD: 1960s: Introduction of RF parallel-plate reactors at 13.56 MHz, operated at tens of mTorr. Cold Electrode Setup: Sample placed on cold electrode (10–20 V drop across RF sheath). RF Power & Pressure: Directly affect plasma density (nₚ) and electron temperature (Tₑ). 300 C instead of 500-600 C

9. Plasma Characteristics Electron Density and RF power Electron Temperature and Pressure

10. Plasma Assisted Etching Techniques(RIE) Process developed for targeted removal of layers by exposing them to plasmas. Pressures Typically less than 10^-6 Torr PECVD and RIE two sides of the same coin.- John W. Coburn and Harold F. Winters in 1979

11. Advantages and Disadvantages Advantages Disadvantages Versatile Processing Conditions Limited Control Over growth Rates Uniform Coating Sorted In the next generation of plasma reactors(Inductively Coupled Plasma) Lower Temperatures Some Important Materials: Artificial Diamonds

12. Some Important Materials Carbon NanoTubes

13. Thanks