Susceptor Structure For Chemical Vapor Deposition Reactor

Abstract

Improved susceptor means for supporting a series of substrates to be coated with a film in a chemical vapor deposition reactor. The susceptor means comprises a supporting frame structure positioned within a reaction chamber surrounded by a source of heat energy. A plurality of separable discrete susceptor slabs, each of which is formed from a material which is capable of absorbing the heat energy emanating from the heat source, are heated to insure uniform eating of the substrates carried by the slabs. The susceptor slabs are supported in a generally vertical orientation at a slight angle to the vertical to insure maintenance of the substrates in recesses formed therein without requiring additional retaining means. The susceptor means is separable from the reaction chamber to facilitate attachment of the susceptor slabs to the frame structure thereof. The susceptor slabs are separable from the frame structure so that the slabs may be horizontally oriented to facilitate loading of substrates therein prior to attachment of the susceptor slabs to the frame structure. The frame structure is operatively connectable with means for rotating the frame structure within the reaction chamber to insure uniform heating of the substrates carried thereby.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of vapor deposition of films of various types on substrates. More particularly, the field of this invention involves the vapor deposition of epitaxial or polycrystalline or amorphous films, for example silicon dioxide and like films, on exposed surfaces of articles, such as silicon wafer substrates commonly used in the electronics industry. Gaseous chemical reactants are brought into contact with heated substrates within a reaction chamber, such substrates being supported by susceptor means which absorb heat energy emanating from a heat source, such as a radiant heater, surrounding the reaction chamber.

This invention further relates to the field of improved susceptor means for supporting substrates during a chemical vapor deposition reaction and to the field of simplifying loading of substrates into position on such susceptor means.

2. Description of the Prior Art

While substrates, such as silicon wafers, have been coated heretofore with epitaxial and other films, such as silicon dioxide or like films, while supported on a susceptor structure, so far as is known, the specific and improved susceptor means disclosed herein is novel. Such susceptor means is designed to produce uniform film coatings on substrates being treated under controlled chemical vapor deposition conditions so that coated substrates of high quality and excellent film thickness uniformity are producible within closely controlled limits.

In chemical vapor deposition systems it is highly desirable to carry out the deposition reaction in a cold wall type reaction chamber. By maintaining the reaction chamber walls in the unheated state, such walls receive little or no film deposition during substrate coating. Cold wall systems are additionally desirable because they permit the deposition of high purity films, such as silicon dioxide or like films thereon. Impurities can be evolved from or permeate through heated reaction chamber walls. Because such impurities would interfer with and adversely affect the purity of the substrate coating, cold wall reaction chambers preferably are employed to preclude such impurity evolution or permeation.

To avoid such problems, chemical deposition processes have been developed which permit heating of a substrate positioned within a reaction chamber without simultaneously heating the reaction chamber walls. Such processes generally involve the use of radio frequency (RF) induction heating of a one piece conducting susceptor positioned within the reaction chamber, the walls of which are formed of non-conducting or insulating material.

For example, RF heating of a one piece graphite susceptor positioned within a quartz reaction chamber for depositing epitaxial and like films has been known generally heretofore. However, such RF heating techniques, while the same generally produce the stated objective in a cold wall reaction chamber, have several inherent and important disadvantages which make the same undesirable under many circumstances. For example, an expensive and bulky RF generator is required which is very space consuming and which must be located close to the film deposition reactor. Also, the high voltage required with the RF coils produces substantial personnel hazards, and RF radiation from the RF coils can and frequently does interfer with adjacent electrical equipment. Also, as noted, a single piece continuous susceptor is required which frequently is difficult and expensive to produce.

As noted, such an RF procedure normally requires the utilization of a one piece electrically conducting susceptor for supporting the substrates to be heated. That is, such induction type reactors normally require one piece susceptors to insure current flow therethrough and to insure maximum efficiency of such a reactor. Also, inductance type reactors normally require single piece susceptors because electrical arcing would normally result if a susceptor of two or more pieces were used because of the different potentials which normally would be encountered in the separate pieces of a two-or-more piece susceptor. Inductance type systems require electrical continuity to insure effective and efficient operative coupling to the generator and therefore such continuity normally dictates the need to use a one piece susceptor. Also RF inductance type systems are considerably more expensive overall than the illustrative radiation heated systems of the type with which this this invention is described.

The same general considerations discussed above with respect to inductance type reactors are generally applicable to resistance type heated reactors as well, and as a result, such resistance heated reactors also commonly use one piece susceptors.

In applicant's assignee's McNeilly et al. U.S. Pat. No. 3,623,712, having an issue date of November 30, 1971, an improved cool wall radiation heated system is disclosed which was designed to replace the RF and other reaction systems utilized theretofore as exemplified by the prior art of record against said patent. The susceptor means of the present invention has been designed as an adjunct improvement for utilization in a cool wall radiation heated reactor of the type disclosed in said McNeilly et al patent. However, because of the novelty of its construction, the susceptor means of this invention may be utilized in reactors of types other than the radiant heated reactor disclosed in said McNeilly et al patent.

SUMMARY OF THE INVENTION

This invention relates generally to an improved susceptor means for supporting a plurality of substrates in a reaction chamber during a chemical vapor deposition reaction during which an oxide, nitride, metal or other similar epitaxial or polycrystalline or amorphous film is chemically vapor deposited on such substrates, such as silicon and other wafers commonly employed in the electronics industry in the manufacture of integrated circuits, transistors and the like. More particularly, this invention relates to an improved multi-piece susceptor structure for supporting a plurality of substrates to be chemically vapor deposition coated within a reaction chamber of a radiant heated or other chemical vapor deposition reactor, such structure being specifically designed to facilitate loading and unloading of substrates to be coated on the susceptor structure.

Still more particularly, this invention relates to an improved susceptor means for utilization in a cold wall chemical vapor deposition reactor for coating substrates with a predetermined type of film. While this invention has particular utility in conjunction with a radiation heated reactor of the type disclosed in said McNeilly patent, and is illustrated and described herein in conjunction with such a reactor, it should be understood that its utilization in other reactor assemblies also is contemplated hereby.

This invention has utility in conjunction with coating substrates with various types of known films, including epitaxial, polycrystalline and amorphous films. While hereinafter reference is directed by way of example primarily to the chemical vapor deposition of epitaxial films, utility of this invention is not restricted to that particular application.

The susceptor means of the present invention includes a supporting frame structure on which are removably supported a series of discrete susceptor slabs each of which is formed from a material which is opaque to the heat energy emanating from the heat source positioned adjacent the slabs. As used herein, the term "opaque" is intended to include within its scpoe those materials which are capable of absorbing energy to produce heat. By way of example herein, the heat source illustrated is of the radiant type which produces radiant energy at a predetermined wave length in the manner described in said McNeilly et al patent.

In the preferred embodiment disclosed herein, such frame structure supports a plurality of susceptor slabs in generally circular orientation and the frame structure is surrounded by the heat source when the susceptor means is positioned in a reaction chamber. Such discrete susceptor slabs may be more easily and less expensively manufactured than the large one piece susceptors used heretofore. When the susceptor means is positioned within a reaction chamber, gaseous chemical mixtures, composed of one or more suitable reactants in known fashion, and as described in detail in said McNeilly et al. patent, are selelctively introduced into the reaction chamber to come into contact with heated substrates supported on the susceptor slabs connected with the frame structure. Such substrates are heated by their supporting susceptor means absorbing energy from the radiant heat source without simultaneously heating the walls of the reaction chamber, which are formed from a material which is transparent to heat energy transmitted at the wave length chosen for the heat source as described in said McNeilly et al. patent.

The supporting frame structure perferably is separable from the reaction chamber, either by removing the frame structure from the reaction chamber or by removing the reaction chamber from around the frame structure, so that access may be had to the frame structure to engage and disengage susceptor slabs therewith prior to and following chemical vapor deposition of films on substrates carried thereby.

Because the susceptor slabs are selectively removable from the frame structure, they may be positioned horizontally when thus removed to simplify loading of substrates in recesses formed therein. When the recesses are thus filled with the desired number of substrates, the slab structures may be engaged with the frame structure and the frame structure may then be reinserted into the reaction chamber, or the reaction chamber may be positioned about the frame sturcture, depending upon the construction of the particular reactor with which the susceptor is to be utilized. When engaged with the frame structure, the susceptor slabs are generally vertically oriented but are inclined towards the vertical axis of the frame structure so that the substrates are maintained in the slab recesses without requiring additional retaining means therefor.

The frame structure includes a vertical shaft which is operativly connectable with means for rotating the frame structure within the reaction chamber to insure uniform heating of the substrates carried by the susceptor means.

From the foregoing, it should be understood that objects of this invention include the provision of improved susceptor means for utilization in a reactor for chemically vapor depositing films on substrates supported thereby; the provision of improved susceptor means including a supporting frame structure carrying a plurality of discrete susceptor slabs each of which is capable of supporting a plurality of substrates to be coated therein; the provision of improved susceptor means comprising a plurality of separable susceptor slabs which are vertically oriented when the susceptor means is in operative position and which may be selectively removed from the frame structure and positioned horizontally to facilitate loading of substrates therein; and the provision of improved susceptor means for rotatably supporting susceptor slabs in a generally vertical orientation during heating thereof in a chemical vapor deposition reactor.

These and other objects of this invention will become apparent from a study of the following description in which reference is directed to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view through a chemical vapor deposition reactor showing one embodiment of the subject susceptor means positioned therein.

FIG. 2 is a horizontal sectional view through the reactor taken in the plane of line 2--2 of FIG. 1.

FIG. 3 is a side elevational view of a portion of the subject susceptor means taken in the plane of line 3--3 of FIG. 2.

FIG. 4 is a partial vertical sectional view through a susceptor slab of the subject susceptor means taken in the plane of line 4--4 of FIG. 3.

FIG. 5 is a vertical sectional view through a chemical vapor deposition reactor showing a modified embodiment of the subject susceptor means positioned therein.

FIG. 6 is a horizontal sectional view through the reactor taken in the plane of line 6--6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several embodiments of radiant heated reactors well suited to carry out an effective chemical vapor deposition procedure are disclosed herein. However, full structural details of such reactors, and their mode of operation, are not described in detail herein. For a full understanding of the construction and operation of such a radiant heated reactor of the type illustrated herein, reference is directed to the aforementioned McNeilly et al. U.S. Pat. No. 3,623,712.

This invention relates specifically to improved susceptor means of the type particularly well suited for utilization in conjunction with such a radiant heated reactor although, it should be understood, that the susceptor structure of this invention has utility in other types of chemical vapor deposition reactors as well.

Two embodiments of the subject susceptor means of this invention are disclosed herein, each of which is shown operatively positioned within a reaction chamber of a radiant heated reactor. Each of such embodiments is shown incorporated into a cold wall reaction chamber the walls of which are transparent (i.e. essentially non-absorbent) to radiant heat energy transmitted from a radiant heat source. The source of such radiant heat in the illustrated embodiments comprises a bank of high intensity lamps, which produce and transmit high temperature heat energy at a wave length which is not intefered with or appreciably absorbed by the walls of the reaction chamber.

The chemical vapor deposition procedure within the reaction chamber is described in detail in said McNeilly et al. patent and reference is directed thereto for an understanding thereof. However, it should be understood that the reactor with which the subject susceptor means is utilizable is designed to produce various chemical reactions and/or thermal pyrolysis reactions to deposit a variety of selective types of epitaxial, polycrystalline or amorphous films, such as silicon, gallium arsenide phosphide, silicon nitride and silicon dioxide, as well as metal films such as molybdenum, titanium, zirconium and aluminum, in accordance with known chemical vapor deposition reactions in the presence of heat.

In that regard, the heat source illustrated desirably comprises a bank of tungsten filament, quartz-iodine high intensity lamps which are commercially available as described in said McNeilly et al. patent. Such lamps are capable of producing high filament temperatures in the range of 5,000.degree. to 6,000.degree. F. The lamps chosen desirably are selected from the type which produce maximum radiant heat energy in the short-wave length range, preferably approximately 1 micron. Such radiant heat energy in such short-wave lengths passes through material found suitable for defining the walls of the reaction chamber, of which quartz is preferred.

Reactors of the type described briefly herein have been effectively used for producing films of the type previously identified with film thickness uniformity of plus or minus 5 percent from substrate to substrate within a given run. Highly effective results can be insured because operating temperatures can be controlled closely and uniformly with the heat source described.

Referring first to the embodiment illustrated in FIGS. 1 through 4, it should be understood that the reactor structure is shown in generally schematic fashion and is intended to be enclosed within a surrounding cabinet (not shown) in and on which the necessary gaseous reactant flow controls, electrical power sources, and other attendant mechanisms are to be housed and mounted. For purposes of understanding the subject invention, only those portions of the reactor necessary to illustrate the environment in which the improved susceptor means of this invention is utilized have been illustrated. It should be understood that those portions of the reactor illustrated are intended to be supported within the aforementioned cabinet in any suitable fashion.

The reactor illustrated in FIG. 1 is generally designated 1 and is defined by an enclosure generally designated 2 within which the aforementioned heat source, generally designated 3, is positioned. Such heat source is defined by a bank of high intensity lamps capable of producing and transmitting radiant heat energy at the short-wave length noted previously. Each of such lamps is designated 4 and is positioned in a cylindrical ring shaped lamp mounting block 5 supported on a plate 6 of enclosure 2.

Lamps 4 are positioned in a series of semi-spherical sockets 7 which are arranged in vertically spaced rows extending in parallel relationship about the inner periphery of the block 5. The lamp mounting block surrounds the reaction chamber of the reactor to be described and is provided with means for cooling the same in the form of a helical coil 8 which surrounds the block and through which a cooling fluid, such as water, is circulated. The cooling fluid enters coil 8 at one end 9 thereof and exits at the other end 11 thereof. Cooling air also may be introduced through the lamp mounting block through the lamp sockets if desired. The inner surface 12 of the lamp block is highly polished for most effective heat radiation.

The heat source thus described surrounds the reaction chamber of the reactor which, in the embodiment shown in FIG. 1, is defined by a quartz bell jar 13 which is transparent to heat energy emanating from the heat source at the wave length noted. Such bell jar surrounds the improved susceptor means of this invention, which is generally designated 14. At its upper end, bell jar 13 is provided with a circular flange 16 by means of which the same is supported in depending fashion from an upper apertured plate 17 which forms part of the aforementioned enclosure 2. At its lower end, the bell jar is provided with an exit passage 18 which is to be connected with suitable conduit means (not shown) for carrying away spent reaction gases from the reaction chamber following a chemical vapor deposition reaction therein.

At its upper end, the reactor is provided with a supporting base plate 19 which rests upon a peripheral shoulder 21 formed as part of the apertured plate 17 of the enclosure 2. Interposed between the base plate 19 and flange 16 of bell jar 13 is a seal member 22 which provides a gas tight seal therebetween. Such seal member 22 is formed of any heat resistant material capable of withstanding the substantial temperatures created within the reaction chamber.

Suitable chemical gaseous reactants of known type are selectively introducible into the reaction chamber through a conduit 23 which is positioned in and extends through an opening 24 provided in base plate 19. Conduit 23 is operatively connected with any suitable source of gaseous reactants (not shown) so that such reactants may be metered in known fashion into the reaction chamber for effecting chemical vapor deposition reactions on substrates positioned therein.

Base plate 19 includes a central boss 26 in which a bearing member 27 is positioned and through which a portion of the susceptor means 14 extends. In that regard, such susceptor means includes a vertically extending shaft 28 which extends through bearing 27. Shaft 28 has an enlarged retaining ring 29 adjacent one end thereof which rests upon the bearing 27 and properly positions the shaft within the reaction chamber in alignment with the heat source described previously.

As noted by the arrow in FIG. 1, shaft 28 preferably is operatively connectable with any suitable means (not shown) to effect rotation thereof within the reaction chamber at any predetermined rate of rotation.

It should be understood that base plate 19, shaft 28 and the remainder of the susceptor means to be described are removable as a unit from within the bell jar by raising the base plate upwardly in the directions of the arrows shown in FIG. 1. Such movement relative to the reaction chamber is effected to simplify loading and unloading of substrates on the susceptor means in the manner to be described.

In addition to shaft 28, the susceptor means includes a supporting frame structure, generally designated 31, which in the embodiment illustrated comprises a pair of horizontally extending plate members 32 and 33 which are welded or otherwise secured to the shaft at vertically spaced locations thereon. As seen in FIG. 3, upper plate 32 is generally octagonal in peripheral configuration while bottom plate 33 is generally circular in peripheral configuration. The configuration of the top plate 32 is determined in accordance with the particular size and capacity of the susceptor means and the octagonal configuration is utilized because eight structures for supporting substrates to be coated are engaged therewith in the embodiment shown.

In that regard, such substrate supporting structures comprise a series of thin susceptor slabs 36, eight in number in the embodiment shown, each of which is designed to support therein a plurality of substrates, designated S, which may be silicon, gallium arsenide, quartz, ceramic or metal wafers (such as molybdenum or tungsten) of the type commonly used in the electronics industry to produce semiconductor devices.

As seen in FIG. 3, each susceptor slab 36 is generally rectangular in configuration and each comprises means for supporting a plurality of substrates S thereon. In the illustrated embodiment such supporting means comprises a plurality of generally circular recesses 37 formed in one surface of the slab, each such recess being provided to receive a substrate S therein for vapor deposition of a chemical film thereon. In the embodiment shown, five vertically spaced recesses 37 are provided for receiving five substrates therein. Depending upon the size of the reactor, more than or less than five recesses may be provided in each such slab.

Although substrate receiving recesses have been shown as the means for supporting substrates on each slab 36, it should be understood that other supporting means could also be used. For example, the substrates could be supported by small integral projections extending from the slab face at vertically spaced locations thereon.

The susceptor slabs are formed from material which is opaque to the heat energy generated by the heat source utilized in the reactor and such slabs may be formed from known materials, such as carbon, silicon carbide coated graphite, or vitreous carbon. However, any high temperature material compatible with chemical vapor deposition reactions may be utilized for forming the susceptor slabs 36.

The supporting frame structure 31 is provided with support means for removably attaching the discrete susceptor slabs thereto. In that regard, it will be noted that the susceptor slabs are generally vertically oriented when they are attached to the supporting frame structure. To that end, the diameter or maximum transverse dimension of the bottom plate 33 of the frame structure is of larger size than the diameter or maximum transverse dimension of upper plate 32. Thus, the susceptor slabs are inclined towards the vertical axis of the susceptor means defined by the axis of shaft 28, at a predetermined degree which may be in the range of 2.degree. to 10.degree. relative to the vertical. Thus, the substrates positioned within the supporting means defined by recesses 37 of the slabs 36 are maintained therein without requiring separate retaining means for that purpose.

The supporting frame structure 31 includes support means for separably retaining the slabs 36 in connection therewith and, in the embodiment illustrated, such retaining means comprises at least one supporting peg or equivalent structure projecting from at least one of the plate structures 32 and 33 of the supporting frame. In the embodiment illustrated, two spaced supporting pegs, genrally designated 41, project from each of the edges of the octagonal periphery of the upper plate 32 of the supporting frame structure. As seen in FIG. 3, each susceptor slab is provided adjacent one end thereof with interfitting structure for mating with the pegs 41 and in the embodiment illustrated such structure comprises a pair of recesses or holes 42 therein provided to receive supporting pegs 41 when such susceptor slab is positioned in engagement with the supporting frame structure.

It should be understood that, if preferred, the pegs (or some equivalent means) could be provided on the bottom plate 33 so that the upper ends of the slabs would rest upon the periphery of the top plate 32 while the bottom ends thereof are supported by such pegs. Also, under certain circumstances, depending upon slab size and weight, the bottom plate 32 can be eliminated if the upper plate is provided with integral structure to maintain the slabs at the desired degree of inclination relative to the vertical axis of the susceptor means.

In any case, however, the susceptor slabs are designed to be easily separable from the supporting frame structure when the susceptor means is separated from within the reaction chamber in the manner described previously.

Ease of separation of the susceptor slabs from the supporting frame structure 31 is an important feature of this invention in that it greatly facilitates loading of substrates into the individual susceptor slabs and loading of filled susceptor slabs onto the frame structure. That is, by separating the susceptor slabs from the supporting frame structure and positioning the same in a horizontal orientation, substrates may be placed in the slab recesses 37 easily and rapidly without danger of manual touching of the central coating areas of the substrates which are being coated. After such substrates have been loaded in the respective slabs, it is then a simple matter to hook the slabs on the supporting pegs 41 without danger of the individual substrates becoming disengaged from their receiving recesses.

While it should be understood that it would also be possible to position the substrate supporting slabs on the supporting pegs while the frame structure is in the operative position shown in FIG. 1, it is obviously a much easier operation to so position the slabs when the frame structure is removed from the reaction chamber for more ready access.

Reference is now directed to FIGS. 5 and 6 for a disclosure of a modified embodiment of the subject susceptor means. In that regard, similar reference numerals are used to identify similar components of the reactor described previously with respect to the embodiment of FIGS. 1 through 4. A similar heat source 3 is utilized and such heat source surrounds a quartz or like bell jar 13' which corresponds generally to the previously described bell jar except for the fact that bell jar 13' does not include a reactant gas passage 18 at one end thereof.

The principal difference between the susceptor embodiments of FIGS. 1 and 5 is that in the FIG. 1 embodiment the susceptor means 14 depends downwardly into the reaction chamber defined by bell jar 13 while in the FIG. 5 embodiment the susceptor means 14 extends upwardly into the reaction chamber defined by the bell jar 13'. In that regard, the flange 16 of bell jar 13' extends within the heat source 3 and rests upon a base plate 19 which forms an integral part of the plate 6 of enclosure 2. Thus, to separate the reaction chamber bell jar from the susceptor means 14 in the FIG. 5 embodiment, it is merely necessary to elevate the bell jar and remove the same from within the heat source.

The susceptor means of FIG. 5 corresponds generally to that described previously in that the same includes a vertical shaft 28 which is operatively connectable with means for rotating the same (not shown). Shaft 28 extends upwardly through boss 26 provided in supporting plate 19 and through the bearing 27 extending through the boss in the manner described previously. Within the reaction chamber,shaft 28 is provided with an enlarged retaining ring 46 which supports the supporting framework 31 of the susceptor means on bearing 27. Such supporting framework includes an upper octagonally shaped plate member 32 and a lower plate member 33' which corresponds generally to the plate 33 described previously except that plate 33' also is formed with an octagonal periphery as seen in FIG. 6.

The upper plate 32 is provided with supporting pegs 41 projecting from the eight edge portions thereof as also seen in FIG. 6 and such pegs removably retain and support eight susceptor slabs 36 in the manner described previously at a predetermined angle relative to the vertical axis defined by the axis of shaft 28. The octagonal lower plate 33' is selectively used in place of a circular lower plate to impart a more stable engagement of the lower ends of the susceptor slabs with such lower plate.

With the embodiment of FIG. 5, while the susceptor slabs are easily removable from the supporting frame 31 when the bell jar 13' is removed, it is normally not necessary to elevate the supporting frame structure from within the heat source in that sufficient clearance is provided between the inner surface 12 of lamp block 5 and the supporting frame structure 31 when the bell jar is removed to permit the susceptor slabs to be hooked on the supporting pegs. However, if desired, the shaft 28 may be slidably positioned within bearing 27 to permit elevation of the supporting framework relative to the heat source so that more ready access to the supporting pegs may be had to further facilitate engagement or removal of the susceptor slabs relative to the supporting framework.

In the embodiment of FIG. 5, the gaseous reactants are introduced into and removed from the reaction chamber bell jar 13' through conduits 47 and 48 which pass through openings 49 and 51 provided in the base plate structure 19 in the manner seen in FIG. 5. Thus, suitable gaseous reactants may be selectively introduced into and spent reaction products withdrawn from the reaction chamber in known fashion.

As mentioned, preferably each of the susceptor embodiments of FIGS. 1 and 5 is connectable with means (not shown) for rotating the supporting framework thereof. While such rotation is not required under all circumstances, relatively slow rotation, in the range of approximately 10 to 15 revolutions per minute, has been found effective to insure uniform heating of the susceptor slabs 36 and the plurality of substrates S carried thereby.

Having thus made a full disclosure of various embodiments of improved susceptor means for supporting substrates to be coated during a chemical vapor film deposition reaction, reference is directed to the appended claims for the scope of protection to be afforded thereto.

Claims

I claim:

1. In a radiant heated reactor for effecting a chemical vapor film deposition reaction on heated substrates positioned therein and heated thereby which includes

A. a radiant heat source, for producing and transmitting radiant heat energy,

B. means defining a reaction chamber, for receiving therein the substrates to be coated, adjacent said heat source and generally surrounded by the same, said chamber being formed from a material which is transparent to radiant heat energy produced by said radiant heat source, and

C. conduit means for introducing gaseous reactants into said reaction chamber and for withdrawing the spent reaction gases from said chamber,

the improvement comprising susceptor structure to facilitate loading and unloading of a plurality of substrates to be coated in said reaction chamber defined by

D. improved multi-piece susceptor means within said reaction chamber for supporting a plurality of substrates thereon during operation of said reactor, comprising

1. a generally vertically extending supporting frame structure positioned within said reaction chamber and selectively separable therefrom, and

2. a plurality of elongated susceptor slabs separably supported in generally vertical orientation by said frame structure generally in alignment with said heat source,

3. means provided on said frame structure for separably retaining said susceptor slabs in engagement therewith,

4. each said susceptor slab including structure cooperable with said means on said frame structure for separably retaining said slabs engaged therewith,

5. each such slab being formed from a material which is opaque to said radiant heat energy and which absorbs the same and is heated thereby,

6. all of such slabs having means on a surface thereof facing said heat source for separably supporting thereon a plurality of substrates to be coated,

7. each such slab being selectively separable from said frame structure and being removable from said reaction chamber so that a plurality of substrates to be coated may be positioned in engagement with or removed from such slab while the same is out of said reaction chamber, whereby loading and unloading of said reaction chamber is facilitated.

2. The susceptor means of claim 1 in which said supporting frame structure includes support means for inclining each of such susceptor slabs at a predetermined angle relative to the vertical axis of said supporting frame so that substrates positioned in engagement with said means on said surfaces are maintained thereon by such inclination of said slabs without requiring additional retaining means.

3. The reactor of claim 1 in which said reactor further includes

E. means operatively connected with said supporting frame structure of said susceptor means for rotating said frame structure about its vertical axis within said heat source during chemical vapor deposition of film on said substrates carried by said susceptor slabs.

4. The reactor of claim 3 in which said susceptor slabs are supported by said supporting frame in a generally circular pattern surrounding the vertical axis thereof.

5. The reactor of claim 1 in which said means defining said reaction chamber depends from a base plate of said reactor and is supported thereby, and in which said susceptor means is suspended within said reaction chamber from said base plate.

6. The reactor of claim 1 in which said means defining said reaction chamber projects upwardly from a base plate of said reactor and is supported thereby, and in which said susceptor means projects upwardly into said reaction chamber.

7. The susceptor means of claim 1 in which said supporting frame structure comprises

a. a vertically extending shaft,

b. vertically spaced plate members secured to said shaft, and

c. retaining means on at least one of said plate members for removably supporting such susceptor slab on said frame structure.

8. The susceptor means of claim 7 in which said retaining means comprises at least one peg projecting from said one plate member, said susceptor slab having at least one hole therein for receiving a supporting peg therein when such slab is supported by said frame member.

9. The susceptor means of claim 8 in which each such peg is formed on the upper plate of said vertically spaced plate members.

10. The reactor of claim 5 in which said susceptor means is vertically movable from said reaction chamber so that said susceptor slab may be readily separated from said supporting frame structure.

11. The reactor of claim 6 in which said reaction chamber is removable from around said susceptor means so that said susceptor slab may be readily separated from said supporting frame structure.