Plasma reactor

Details Plasma reactor Plasma reactor

1997-03-28

1999-09-21

Breneman, R. Bruce

Coating apparatus

Gas or vapor deposition

With treating means

118723ME, 156345, 20429838, 31511121, C23C 1600

Patent

active

059548827

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a plasma reactor for generating and maintaining a plasma, specifically for deposition of diamond, comprising a frequency generator and a resonant cavity to which electromagnetic waves are fed by the frequency generator, with a reaction unit being suited for introduction in the resonant cavity bounded by a wall, in a region of high field strength.
Such a plasma reactor is known from the publication "Diamond Deposition Technologies" by P. K. Bachmann and W. van Enckevort, published in the magazine Diamond and Related Materials, volume 1, pages 1021 through 1034, in 1992. In this plasma reactor, microwaves generated by means of a frequency generator are via a pin type coupler introduced in a resonant cavity which is fashioned as a resonant cylinder formed by a cylindrical pipe closed endwise. On the sealed end of the resonant cylinder, opposite the pin type coupler, there is a reaction unit arranged with a substrate to be coated from a gas phase formed by an ignited plasma.
In the prior plasma reactor, the situation and shape of the plasma depends very sensitively on process parameters such as gas pressure and coupled microwave power. Moreover, these two process parameters are not selectable independently of one another, but are adjustable in mutual dependence only within a relatively narrow correlation range. Leaving the correlation range occasions frequently an abrupt spatial displacement of the plasma, which, besides disturbing the deposition process, destroys within a short time, e.g., a quartz glass enclosing the substrate and bounding the reaction volume.
A further disadvantage of the prior plasma reactor is its great dependence of the plasma situation on the geometric constraints and the arrangement of the reaction unit.
The objective underlying the invention is to create a plasma reactor which, with a mutually very extensively independent selection of process parameters such as gas pressure and coupled electromagnet power, is characterized by a spatially stable plasma that is homogeneously distributed over the deposition area of a substrate.


SUMMARY OF THE INVENTION

This object is achieved in that the resonant cavity features a wall giving the resonant cavity a cross section tapering in summit regions, the taper of the resonant cavity cross section in the summit regions being such that the field strength distribution established by the wall features at least two main peaks whose maximum field strength is elevated as compared to the field strengths of adjacent secondary peaks.
Fashioning the resonant cavity ellipsoidal, for example, generates a field mode as overlay of eigenmodes with at least two main peaks which in their field strength are distinctly elevated above the field strengths of adjacent secondary peaks. The spatial distribution of these field modes is extensively independent of the electromagnetic power of a burning plasma coupled in the resonant cavity, and specifically also of slight deformations in the resonant cavity wall. With an arrangement of the reaction unit in the region of one of the main peaks a plasma can now be generated that is spatially stable and at variations of process parameters such as gas pressure and/or coupled electromagnetic power most extensively uninfluenced in its situation and which burns homogeneously over a relatively large region, which plasma allows producing hard material layers, specifically diamond layers, in the thin-film technology, performing plasma polymerization and powder synthesis processes in the materials synthesis and nitrating and etching treatments in the plasma surface treatment.
In preferred embodiments, the resonant cavity is fashioned as ellipsoid, as a segmented ellipsoid formed sectionally of ring-shaped conic wall segments or as an asymmetric ellipsoid expanded in diameter in the region of a main peak. In another embodiment, the tapering regions are provided as rotationally symmetric paraboloid sections joined together via a cylindrical section. Common to these embodiments of the

REFERENCES:
patent: 4563240 (1986-01-01), Shibata et al.
patent: 4585668 (1986-04-01), Asmussen et al.
patent: 4866346 (1989-09-01), Gaudreau et al.
patent: 5433789 (1995-07-01), Kakehi et al.
patent: 5646489 (1997-07-01), Kakehi et al.
Diamond Deposition Technologies Article, by P.K. Bachmann and W. van Enckrt (1992).

Affiliated with

Also associated with

Rating

Plasma reactor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Plasma reactor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma reactor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-76288