plasma deposition ppt

Introduction about Plasma -deposition:

Introduction about Plasma -deposition By:- Chandan kumar pathak 8EC-13 Passionate_chandan@rediffmail.com

Introduction :

Introduction What is a Plasma? >The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir , an American chemist and physicist, in 1929 >Plasma is just gas, with one additional form of decomposition, that of electrons broken free of their molecules or atoms. >Instead of all molecules being neutral, some are positive, some are negative, and many are neutral like in a normal gas.

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Neutral Gas Plasma

Where can we find Plasma?:

Where can we find Plasma?

COLD PLASMA:

COLD PLASMA It isn’t really cold Typical electron temperatures for cold plasma are in the range of thousands of degrees Only a small fraction of the gas molecules are ionized Degree of ionization is usually of the order of 1% Often created using strong electric fields E.g :- Fluorescent Lights Strobe Lights Experimental fusion Research devices Generally man-made

HOT PLASMA:

HOT PLASMA It is really hot Like the sun (1,50,00,000 °C at the core ) The molecules are nearly, if not fully ionized Degree of ionization is close to 100% Created by heating the molecules to extremely high temperatures E.g :- The sun and the stars The Aurora Borealis, Called the Northern Polar Lights

Formation of plasma as Astroligical:

Formation of plasma as Astroligical

LAPD(large plasma device):

LAPD(large plasma device) • 128 ports • 40 cm dia plasma • 10 meter long • Quiescent δ n/n=3% 400 G ≤ Bz ≤ 1.7Kg • Fully ionized • Reproducible • 1 Hz rep rate

Sizes in LAPD:

Sizes in LAPD

Plasma mechanism firing sequence:

Plasma mechanism firing sequence A. Warhead before firing; primary (fission bomb) at top, secondary (fusion fuel) at bottom, all suspended in polystyrene foam. B. High-explosive fires in primary, compressing plutonium core into supercriticality and beginning a fission reaction. C. Fission primary emits X-rays which are scattered along the inside of the casing, irradiating the polystyrene foam. D. Polystyrene foam becomes plasma, compressing secondary, and plutonium sparkplug begins to fission. E. Compressed and heated, lithium-6 deuteride fuel produces tritium and begins the fusion reaction. The neutron flux produced causes the U-238 tamper to fission. A fireball starts to form.

Fire weapon action:

Fire weapon action The high explosives surrounding the core of the primary fire, compressing the fissile material into a supercritical state and beginning the fission chain reaction. The fissioning primary emits x-rays, which "reflect" along the inside of the casing, irradiating the polystyrene foam (see below for a note on what "reflection" means in this context). The irradiated foam undergoes a phase transition, becoming a hot plasma, pushing against the tamper of the secondary, compressing it tightly, and beginning the fission reaction in the spark plug. Pushed from both sides (from the primary and the spark plug), the lithium deuteride fuel is highly compressed and heated to thermonuclear temperatures. Also, by being bombarded with neutrons, each lithium-6 atom is split into two tritium atoms. Then begins a fusion reaction between the tritium and the deuterium, releasing even more neutrons, and a huge amount of energy. The fuel undergoing the fusion reaction emits a large flux of neutrons, which irradiates the U-238 tamper (or the U-238 bomb casing), causing it to undergo a fission reaction, providing about half of the total energy.

Fundamental plasma parameters:

Fundamental plasma parameters 1.Frequencies F α applied Magnetic field. 2. Length L α temperature 3. Velocities V α applied potential

Measurment of parameters:

Measurment of parameters 1.Temperature

2.Potential measurment:

2.Potential measurment Gives a relation between Standard potential and floating potential .

3.Gas pressure measurment:

3.Gas pressure measurment 1.The reactor was based on a laminar flow reactor design 2.Frequency of about 33 kHz and a peak potential of approximately 10 kV.

4. Current measurment:

4. Current measurment > By Fizeau effect:-

Controlling the plasma:

Controlling the plasma Generally for controlling the plasma we will try to control number of free ions and temperatare of reactor chamber or its species. where e is the electron charge, k is the Boltzmann constant and I e and U are the electron current of the probe characteristics and the bias voltage, respectively .

Application of PLASMA:

Application of PLASMA 1.Thin film deposition a)-Evaporation b)-Sputtering c)- CVD

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2. Plasma-immersion ion implantation 3. Plasma application in PCB 4.Plasma cutting 5.Plasma spraying

Conclusion…………….:

Conclusion……………. Plasma is Electro-magnetic system in nature. It Following Maxwell-Boltzmann law.

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Thanks……………