磁控溅射原理介绍(英文)

MIRDCWhat is magnetron sputtering?Magnetron Sputtering is a plasma vacuum coating technique and here are some of the questions that will be answered in this section: What’s sputtering? What’s a magnetron? What’s a plasma?Main Menu

MIRDCWhat is sputtering?Atom, ion Atom or ion with kinetic energye-SurfaceThe impact of an atom or ion on a surface produces The impact of an atom or ion on a surface produces sputtering from the surface as a result of the momentum sputtering from the surface as a result of the momentum transfer from the in-coming particle. transfer from the in-coming particle. Unlike many other vapour phase techniques there is no Unlike many other vapour phase techniques there is no melting of the material. melting of the material.Main Menu

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MIRDCThe history of sputtering?The verb to SPUTTER originates from Latin SPUTARE The verb to SPUTTER originates from Latin SPUTARE (To emit saliva with noise). (To emit saliva with noise). Phenomenon first described 150 years ago… Phenomenon first described 150 years ago… Grove (1852) and plücker (1858) first reported vaporization Grove (1852) and plücker (1858) first reported vaporization and film formation of metal films by sputtering. and film formation of metal films by sputtering. Key for understanding discovery of electrons and positive ions Key for understanding discovery of electrons and positive ions in low pressure gas discharges and atom structure in low pressure gas discharges and atom structure (J.J. Thomson, Rutherford), 1897-(J.J. Thomson, Rutherford), 1897-Other names for SPUTTERING were SPLUTTERING Other names for SPUTTERING were SPLUTTERING and CATHODE DESINTEGRATION. and CATHODE DESINTEGRATION.Main Menu

MIRDCWhat is a MagnetronA Magnetron is comprised of : A CATHODE = electron source An ANODE = electron collector A combined ELECTRIC & MAGNETIC FIELD B EElectric Field E Magnetic Field Bx xE+B+Ex x x Bxxxxx-Main Menu

MIRDCWhat is a MagnetronThe most common type of magnetron can be found inside a microwave oven. This is a magnetron tube.Main Menu

MIRDCWhat is a plasma?Plasma is a fluid of positive ions and electrons in a quasi-neutral electrical state The vessel that contains this fluid is formed by electric and magnetic fields. In many plasma coating applications positive ions are generated by collisions between neutral particles and energetic electrons. The electrons in a plasma are highly mobile, especially compared to the larger ions (typically argon for sputtering) Control of these highly mobile plasma electrons is the key to all forms of plasma controlConversion of a neutral atom into an ion by electron collision in a plasma0+e-1+e-Main Menu

MIRDCElectron motion in a combined electric & magnetic fieldeBB x e-S E B ExBNNSe-Main Menu

MIRDCA magnetron sputtering plasmaConfinement between a negatively biased target and ‘closed’ magnetic field produces a dense plasma. High densities of ions are generated within the confined plasma, and these ions are subsequently attracted to negative target, producing sputtering at high rates.++Negatively biased target--VResulting erosion of the sputter targetHigh density plasma generated by the combine electrical and magnetic fieldMain Menu

MIRDCMagnetron sputtering plasmaExample of a circular targetTargetPlasmaMain Menu

MIRDCPlasma physicsBasic concepts Basic concepts Sustaining a discharge Sustaining a discharge-Secondary emission -Ionising collisions -Secondary emission -Ionising collisionsMean free paths Mean free paths Magnetic trap Magnetic trapMain Menu

MIRDCBasic concepts‘Gas’ of charged particles ‘Gas’ of charged particles Electrons (negative) Electrons (negative) Ions (positive) Ions (positive) Plasma Parameters Plasma Parameters Density (ne,, nii) Density (ne n ) Electron temperature (Te) Electron temperature (Te) Usually measured in electron volts (1eV = 12000°c) Usually measured in electron volts (1eV = 12000°c) Plasma potential (Vp) Plasma potential (Vp)Main Menu

MIRDCSustaining a dischargeParticles lost from the discharge must be replaced. This can be achieved by Secondary emission of electrons Ionising collisionsMain Menu

MIRDCSecondary electron emissionElectrons lost from the discharge can be replaced by secondary emission - electrons liberated from the target due to ion impact. This is characterised by the parameter γ. For every ion impacting on the target γ electrons are released by secondary emission. For most metals, γ ~ 0.1, and is insensitive to ion impact energy (for ion energies < 1keV).Ar+Main Menu

MIRDCIonising collisionsIons and electrons lost from the discharge can be replaced by ionising collisions e- + Ar e- + e- + Ar+eeAr+ Ar e-Main Menu

MIRDCDouble IonisationIf an electron collides with an Argon ion, there is a possibility of the Argon losing another electron, becoming doubly ionised e- + Ar+ e- + e- + Ar++eeAr++ Ar+ e-Main Menu