Use of an externally applied axial magnetic field to control ion/neutral flux ratios incident at the substrate during magnetron sputter deposition

Journal Article · Tue Sep 01 00:00:00 EDT 1992 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)

DOI:https://doi.org/10.1116/1.577812· OSTI ID:7029938

Petrov, I; Adibi, F; Greene, J E ^[1]; Sproul, W D ^[2]; Muenz, W ^[3]

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1. Dept. of Materials Science, the Coordinated Science Laboratory, and the Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)
2. BIRL, Northwestern University, Evanston, Illinois 60201 (United States)
3. Hauzer Techno Coating Europe BV, Groethofstaat 22b, 5916 PB Venlo (Netherlands)

The development and characterization of an ultrahigh vacuum unbalanced'' dc magnetron sputter deposition system with a variable external axial magnetic field for controlling the ion-to-neutral flux ratio at the substrate during deposition with low negative substrate biases is reported. The target assembly is a planar-magnetron (PM) with a toroidal magnetic-field electron trap created using a set of permanent magnets. A pair of Helmholtz coils, located outside the vacuum chamber, produces an additional magnetic field {ital B}{sub ext} which is uniform along the axis orthogonal to both target and substrate surfaces. The value and sign of {ital B}{sub ext} has a strong effect on the plasma density near the substrate, and hence on the ion flux {ital J}{sub {ital i}} incident at the substrate, with only a minor effect on the target-atom flux. For a Ti target sputtered in pure Ar at 20 mTorr with a target-substrate separation of 6.5 cm, changing {ital B}{sub ext} from {minus}50 G (opposing the field of the outer PM pole) to +600 G (reinforcing the field of the outer PM pole) varied the ion-to-Ti flux ratio {ital J}{sub {ital i}}/{ital J}{sub Ti} incident at the substrate by a factor of 60 from 0.1 to 6 with the bias held constant at any desired negative value between {congruent}{minus}15 V (limited by the difference between the floating {ital V}{sub {ital f}} and plasma {ital V}{sub {ital p}} potentials) and the highest negative values examined, {minus}100 V. For reactive sputter deposition in N{sub 2} (where the primary ion is N{sub 2}{sup +}) under the same conditions, {ital J}{sub {ital i}}/{ital J}{sub Ti} varied by a factor of 50 from 0.7 to 35. {ital V}{sub {ital p}} was negative with {ital B}{sub ext} set to positive values and ranged from {congruent}0 ({ital B}{sub ext}=0) to {minus}13 V ({ital B}{sub ext}{ge}+200 G) in Ar and 0 to {minus}20 V in N{sub 2}.

• DOE Contract Number: FG02-91ER45439
• OSTI ID: 7029938
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Vol. 10:5; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
TITANIUM
SPUTTERING
ARGON
MAGNETIC FIELDS
MAGNETRONS
NITROGEN
ULTRAHIGH VACUUM
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FLUIDS
GASES
METALS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
NONMETALS
RARE GASES
TRANSITION ELEMENTS
420200* - Engineering- Facilities
Equipment
& Techniques