1.6 Magnetron Sputtering Perpendicular Electric Magnetic Fields

In magnetrons, electrons are ideally trapped near the target, enhancing the ionization efficiency. - The most widely commercially practiced sputtering method  high deposition rate ~ 1m/min for Al, (10 times higher than conventional sputtering)  reducing electron bombardment of substrate  extending the operating vacuum range

1. 8. 3 Reactive sputtering - sputtering metallic target in the presence of a reactive gas - eq). mixed with in gas (Ar) oxides – Al2O3, SiO2, Ta2O5 (O2) nitrides – TaN, TiN, Si3N4 (N2, NH3) carbides – TiC, WC, SiC (CH4, C2H4, C3H8)

A : compounds B : doping, alloys A : all N2 reacts with Ta film  doped metal (Ta N0.01) - atomic ratio of N to Ta increases as N2 pressure increase B : Compound formation an the metal target plasma impedance is effectively lower in state B than in state A, since ion-induced secondary electron emission is much higher for compounds than for metals. A B

1. 9 Hybrid and Modified PVD Processes 1. 9. 1 Ion plating - Relatively uniform coating of substrates with complex shapes is achieved.  coat steel and other metals with very hand films for use in tools and wear-resistant applications. Ti, Zr, Cr, Si in (N2, O2, CH4) + Ar plasma  extremely good adhesion  high “throwing power”  reduce shadowing effect  near bulk density  suppress undesirable columnar growth  RIP (reactive ion plating) Nitrides, Oxides, carbides

1. 9. 2. Reactive Evaporation Processes - metal reacts with a gas to produce compound deposits (oxides, carbides, nitrides) - ARE (activated reactive evaporation) process Plasma activation lowers the energy barrier for reaction  compete with CVD  no need for metal-containing compound gases

ground, float, biased -2 ~ -5 KeV inert ion dc bias 20-100 V e-

1. 9. 3 Ion-Beam-Assisted Deposition - Use of broad-beam (Kaufman) ion source - Unlike plasma, independently control ion flux and energy - 1mA/cm2  6.25  1015 ions/cm2sec, low energy (10ev)  enhancement of the density and index of refraction of optical coating - stress, hardness, adhesion, refractive index, step coverage

1. 9. 4. Ionized Cluster Beam (ICB) Deposition - Ionized clusters affects film nucleation and growth 1. Increase the local temperature at impact 2. Surface diffusion of atoms is enhanced 3. Activated centers for nucleation are created 4. Coalescence of nuclei is fostered 5. Surface is sputter-cleaned 6. Chemical reactions between condensing atoms and substrate are favored - Strong adhesion, Smooth surface, no columnar growth low temperature growth high quality single crystal growth (epitaxial film) vacuum cleaness (10-7 torr)