Lecture 6

chichi's version from 2018-02-27 00:55

Section 1

Question Answer
Sputteringutilizes ions to knock atoms out of a target that acts as an electrode, and subsequently deposit then on a surface acting as another electrode
CVD reaction mechanisms (Step 1)Mass transport of the reactant in the bulk
CVD reaction mechanisms (Step 2)Gas-pase reactions (homogeneous)
CVD reaction mechanisms (Step 3)Mass transport to the surface
CVD reaction mechanisms (Step 4)Adsorption on the surface
CVD reaction mechanisms (Step 5)Surface reactions (heterogeneous)
CVD reaction mechanisms (Step 6)Surface migration
CVD reaction mechanisms (Step 7)Incorporation of film (constituents, island formation)
CVD reaction mechanisms (Step 8)Desorption of by-products
CVD recation mechanisms (Step 9)Mass transport of by-products

Section 2

Question Answer
Energy sources for depositionThermal, plasma, Laser, Photons
Depostition_____will be conformal so it is of tremendous use to coat complex shapes
Chemical Vapor Depositionchemical reaction of volatile compound of the material be deposited (precursor), with another gas, to produce a nonvolatile solid tat deposits atomistically (or molecularly) on a substrate suitably placed in the deposition chamber
_____ chamber (reactor) runs at pressures that is relatively higher compared with PVD. Typically, pressure ~0.01 atm (plus or minus)CVD
_____ is heated to allow for surface diffusion and to control the film morphologySubstrate

Section 3

Question Answer
Pulsed Laser Depositionmethod of thin film growth involves evaporation of a solid target in an Ultra High Vacuu chamber by means of short and high-energy laser pulses, and deposition of the vapor on a substrate
Advantages of PLDflexible an easy to implement, growth in any environment, target: just about any materials, exact transfer of complicated materials (YBCO super conductor oxides)- stoichiometry, variable deposition and growth rate (laser pulse strength, duration frequency), epitaxy at low temperature
Disadvantages of PLDuneven coverage (in some cases), high defects (not in all cases), well suited for small scale film growth only, complex physics/mechanisms
____________________bare all used to produce films and other nanostructures that normally involved crystalline systemsPVD, CVD and PLD
Crystallographic relationship between the deposited material and substrateEpitaxial systems

Section 4

Question Answer
EpitaxyDeposition of thin layers of one crystal on top of another crystal
Homoepitaxy(A) crystal = (B) crystal
Heteroepitaxy(A) crystal =/ (B) crystal

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