EP2612351A1

EP2612351A1 - Substrate heating device

Info

Publication number: EP2612351A1
Application number: EP11764119.1A
Authority: EP
Inventors: Laurent Despont; Markus Poppeller; Ralph Schmoll
Original assignee: Oerlikon Solar AG
Current assignee: TEL Solar AG
Priority date: 2010-09-03
Filing date: 2011-09-02
Publication date: 2013-07-10
Also published as: CN103081084A; WO2012028704A1; KR20130102577A; JP2013538455A

Abstract

The invention relates to a susceptor for supporting a substrate (9) within a vacuum process chamber, comprising a flat surface (11) for placing the substrate (9) thereon such that the substrate (9) is in thermally conductive contact with the surface (11), whereby the susceptor (1) comprises at least three adjacent zones (5, 6, 8), an outer zone (8), a middle zone (6) and an inner zone (5), the zones (5, 6, 8) arranged concentrically around each other and extending along the surface (11), the outer zone (8) completely surrounds the middle zone (6) and the middle zone (6) completely surrounds the inner zone (5), the inner zone (5) comprises at least one inner heating element (13) affecting the inner zone (5), the outer zone (8) comprises at least one outer heating element (19) affecting the outer zone (8), the middle zone (6) exhibits a maximal thickness (15) that is smaller than the minimal thickness (12) of the inner zone (5) and smaller than the minimal thickness (16) of the outer zone (8), each thickness (12, 15, 16) extending perpendicular to the surface (11). Thus, the invention allows for providing a smooth temperature profile over the complete surface (11) area resulting in a highly uniform substrate (9) temperature and thus in an improved thickness (12, 15, 16) uniformity of a coating to be provided e.g. in a chemical vapour deposition process.

Description

SUBSTRATE HEATING DEVICE

Technical Field

The invention relates to a susceptor for supporting a substrate within a vacuum process chamber, comprising a flat surface for placing the substrate thereon such that the substrate is in thermally conductive contact with the surface. More precisely, the invention relates to establishing a highly uniform substrate temperature on large area substrate surfaces. In particular, the invention describes a high uniformity heating system for the substrate having preferably a non-circular shape in a vacuum environment. This heating system can be applied to many coating or substrate treatment processes working at temperatures higher than room temperature.

Background Art

Thin film deposition or coating processes are well known in the art. Since then, deposition uniformity is an important criterion, especially in the production of large area coatings. In thin film technology nowadays layer properties realized on small scale need to be extended to large area substrates. In general, it has to be considered that the tighter the specification for the integration on a small area, the better the uniformities need to be on a larger area. A typical example is the IC industry, where several thin film layers are adjusted to each other. This adjustment needs to be maintained over the whole substrate area, which requires good uniformity on all involved layers in all their critical properties over the whole wafer.
Thin film solar cell application is a similar example. Here the cell properties allowing high efficiency need to be applied over the whole integrated module. Areas with properties “out of specification” will deteriorate individual cells. Such a cell will exhibit a lower efficiency causing a higher resistance in the serial connection. As a consequence, areas of bad cell properties reduce the overall performance of the complete solar module.
For chemical vapour deposition (CVD) processes, temperature uniformity is one of the most important factors. Chemical reactions during CVD processes exhibit the so-called Arrhenius behaviour where the deposition rate shows an exponential dependence on process temperature. As a consequence, a highly uniform substrate temperature is required to get good thickness uniformity.
Current CVD systems use a variety of measures to get a uniform substrate temperature. Prior art systems use a hot plate or a susceptor, whereby the hot plate respectively the susceptor means an essentially flat surface fit for accommodating a substrate and transferring heat to the substrate such that a.m. requirements in terms of uniform heat distribution are being met. That surface can be established as one surface of a plate having at least the size of the substrate area to be heated or temperature controlled. Such a hot plate may contain several independent heating zones with different heat inputs. In general, the perimeter of the hot plate, i.e. edges and corners, needs to be heated to a higher temperature than the centre to overcome the heat losses due to higher thermal radiation of the hot plate and the substrate at the periphery.
A solution known in the art for heating is attaching electrical heating elements to the hot plate or to integrate the heating elements such as a resistance heating. The better the fitting between heating element and hot plate the faster the response to temperature changes in the hot plate.
There are several approaches to locally control the heat intake into the hot plate. An overview of different heating approaches is documented in US 6,962,732. One of the possible solutions to generate a uniformly heated substrate is to use different heating zones with thermocouples attached to each of the heating zones. The temperature of each zone is set to a specific value which allows the substrate temperature to be more uniform. The temperature settings are empirically determined.
A more sophisticated method of controlling the temperature on a hot plate is to observe the substrate heat uniformity by thermo-camera measurements. The heating zones are tuned accordingly, so that a uniform temperature reading is seen over the whole substrate. That approach allows the generation of a uniform temperature profile without influencing other parameters.
Alternatively, the temperature of the hot plate can be tuned after investigating layer properties resulting from a manufacturing process using the hot plate. One modifies the heating zone temperatures until uniform layer properties are obtained. This method is widely used in commissioning of vacuum equipment. The coating property uniformity, however, is not only influenced by the temperature but also by the gas flow and geometry of the deposition equipment. So flow non-uniformities may be compensated by the temperature tuning of the hot plate.
Heating rectangular substrates is challenging, as, in particular, the substrate corners and edges are more strongly affected by thermal radiation to the surrounding cooler chamber. One would expect that this can easily be compensated by increasing the heat input into such regions. However, it is difficult to get sufficient heat into the hotplate corner region by simply wiring a denser heating pattern, of resistor heating elements, e. g., compared to the other parts of the hot plate. Changing such heating patterns means substantial, i.e. mechanical, changes of the hot plate which is expensive and time-consuming. One solution to this problem would be to individually heat the corner zones and thus electrically adjusting the heat emission into the hot plate. This approach has turned out to be impractical. Indeed, most of the heat transferred into the corners with such individual heating zones will also dissipate to cooler zones of the hot plate, thus influencing the whole hotplate temperature distribution. Thermally insulating the regions from each other could avoid this but will result in a local temperature change in the insulating area.
Currently all solutions proposed in prior art encounter this fundamental dilemma. Most susceptor or hot plate materials are conductive materials and they should conduct the heat of the heating wires or heating elements to the substrate as efficiently possible. For example Al, Cu or Carbon are commonly used as susceptor material. Less conductive materials would require a more dense wiring of heating elements to get uniform heating. The well-conducting material is basically smearing out local heat maxima generated by the heater wire location. This effect however is counterproductive on the edges and the corners of the susceptor. There strong heat maxima are needed to compensate the edge and corner heat losses of the substrate. Simply overheating the edge and corner zones will increase the temperature of the centre heat zone as well.
An example can demonstrate this effect, as shown in Figure 1 and 2. A susceptor 1 containing four independently operating and controlled heating wires 2, 3, 4 is used. All heating wires 2, 3, 4 are mounted on a one-piece hot plate, i.e. on the substrate 1. The four heating wires 2, 3, 4 are forming 4 different zones 5, 6, 7. The first zone 5 is the centre zone heating most of the substrate 9. The second zone 6 is an optional intermediate zone equalizing the temperature differences between the first zone 5 and the second zone 6. The third zone 7 is heating the substrate 9 edge. For these three zones 5, 6, 7 the heating wires 2, 3, 4 are mounted from below the hot plate 1 as indicated in Figure 2, wherein the second zone 6 has been omitted.
The centre zone 5 has a wider spacing in wiring 2 than the edge zone 7. The rim heater zone 8 with heat element 4 is arranged on top of the hot plate 9, but recessed from the heating surface. It is secured by an edge bar 10 on the hot plate 9 and protected from contamination by the CVD process. The substrate 9 is slightly larger than the susceptor 1 surface so that the edge of the substrate 9 is overlapping and thus heated by the edge bar 10.
The following table shows the temperatures set by the operator and the temperature actually reached by the hot plate 9 as indicated by thermocouples attached within the specific zones 5, 6, 7, 8.
Operator set point Actual temperature reading
First zone 5 180 °C 181 °C
Second zone 6 185 °C 195 °C
Third zone 7 195 °C 195 °C
Rim zone 8 210 °C 210 °C
As can be seen in this overview, the second zone 6 is overheated above its target temperature, due to the influence of the temperature settings of the first zone 5 and the third zone 7. Accurate heating of the second zone 6 area is not possible due to the cross talk of the heating zones 5, 6, 7, 8.
Nevertheless it is necessary to increase the edge and rim zone 8 temperatures well above the center zone’s 5 temperature, since otherwise the substrate 9 edge temperature is too low to allow uniform growth.
A solution to the problem of crosstalk of heat between different zones 5, 6, 7, 8 would be the manufacturing of the susceptor 1 from several thermally isolated pieces. It could be foreseen that a centre zone plate 5 is installed surrounded by a separate rim zone 8 frame which is also independently heated. However, this solution has several drawbacks. First, it is not manufactured from one piece of susceptor 1 material. This makes the manufacturing difficult and expensive since the tolerances between the different susceptor 1 plates have to be low enough to allow the uniform substrate 9 heating. Secondly, it is very difficult to have a smooth temperature profile over the gaps between centre zone 5 and rim zone 8. Depending on the substrate 9 thickness a desirable smearing between the two zones 5, 8 may not be sufficient to compensate the heat losses due to the interface of centre zone 5 and rim zone 8.

Disclosure of Invention

Therefore, it is an object of the present invention to overcome before described disadvantages of prior art, i.e. to provide a susceptor for establishing a highly uniform substrate temperature for a large area substrate surface.
This object is achieved by the independent claims. Advantageous embodiments are detailed in the dependent claims.
Particularly, the object is achieved by a susceptor for supporting a substrate within a vacuum process chamber, comprising a flat surface for placing the substrate thereon such that the substrate is in thermally conductive contact with the surface, whereby the susceptor comprises at least three adjacent zones, an outer zone, a middle zone and an inner zone, the zones arranged concentrically around each other and extending along the surface, the outer zone completely surrounds the middle zone and the middle zone completely surrounds the inner zone, the inner zone comprises at least one inner heating element affecting the inner zone, the outer zone comprises at least one outer heating element affecting the outer zone, and the middle zone exhibits a maximal thickness that is smaller than the minimal thickness of the inner zone and smaller than the minimal thickness of the outer zone, each thickness extending perpendicular to the surface.
Surprisingly, it has been found that providing a susceptor manufactured out of a single piece, for example Al, Cu and/or carbon, and having at least three different zones provides a highly uniform substrate temperature over the overall substrate surface, if the middle zone between the outer zone and the inner zone comprises a thickness that is smaller than of the surrounding zones, i.e. of the inner zone and the outer zone, and whereby both the inner zone and the outer zone comprise heating elements for affecting the substrate in the respective zone. With such susceptor according to the invention it is possible to provide strong heat maximas at the edges and corners of the substrate while not negatively affecting, i.e. overheating, the substrate in the area of the inner zone. Thus, the invention allows for providing a smooth temperature profile over the complete surface area resulting in a highly uniform substrate temperature and thus in an improved thickness uniformity of a coating to be provided e.g. in a chemical vapour deposition process. In turn, the susceptor according to the invention decreases manufacturing costs while improving substrate coating quality. In sum, the susceptor provides for improved coating layer properties compared to prior art systems.
The term “processing” in sense of the current invention comprises any chemical, physical and/or mechanical effect acting on the substrate.
The term “substrate” in sense of the current invention comprises a component, part or workpiece to be treated with the vacuum processing system according to the invention. A substrate includes but is not limited to flat-, plate-shaped part having rectangular, square or circular shape. Preferably, the substrate is suitable for manufacturing a thin film solar cell and comprises a float glass, a security glass and/or a quartz glass. More preferably, the substrate is provided as an essentially, most preferably completely flat substrate having a planar surface of a size ≥ 1 m², such as a thin glass plate.
The term “vacuum processing” or “vacuum treatment system” in sense of the current invention comprises at least an enclosure for the substrate to be treated under pressure lower than ambient atmospheric pressure.
The term “CVD”, chemical vapour deposition, and its flavours, comprises in sense of the current invention a well-known technology allowing for the deposition of layers on heated substrates. A usually liquid or gaseous precursor material, the gas, is being fed to a process system, where a thermal reaction of the precursor results in deposition of the layer. Often, DEZ, diethyl zinc, is used as precursor material for the production of TCO layers in a vacuum processing system using low pressure CVD, LPCVD. The term “TCO” stands for transparent conductive oxide, i.e. TCO layers are transparent conductive layers, whereby the terms layer, coating, deposit and film are interchangeably used within this invention for a film deposited in vacuum process, be it CVD, LPCVD, plasma enhanced CVD (PECVD) or physical vapour deposition (PVD).
The term “solar cell” or “photovoltaic cell”, “PV cell”, comprises in sense of the current invention an electrical component, capable of transforming light, essentially sunlight, directly into electrical energy by means of the photovoltaic effect. A thin film solar cell usually includes a first or front electrode, one or more semiconductor thin film PIN junctions and a second or back electrode, which are successively stacked on a substrate. Each PIN junction or thin film photoelectric conversion unit includes an i-type layer sandwiched between a p-type layer and an n-type layer, whereby “p” stands for positively doped and “n” stands for negatively doped. The i-type layer, which is a substantially intrinsic semiconductor layer, occupies the most part of the thickness of the thin film PIN junction, whereby the photoelectric conversion primarily occurs in this i-type layer. Thus, the substrate is preferably a substrate used for manufacturing a thin film photovoltaic cell.
The term “flat” comprises in sense of the current invention a surface that is not rough, i.e. does not have grooves or alike. Preferably the term “flat” means that the surface roughness grade of the respective surface is ≤ N9.
According to a preferred embodiment of the invention, the minimal thickness of the inner zone is greater than the maximal thickness of the outer zone. Such an embodiment advantageously further provides a uniform substrate temperature across the surface as having a outer zone with a smaller thickness than the inner zone allows for a more detailed control of the temperature of the outer zone respectively of the substrate border and/or edges facing the outer zone.
Generally, the smaller thickness of the middle zone can be realized by any means known from prior art, for example by long holes, slits and/or drilling. However, according to an especially preferred embodiment of the invention the susceptor comprises at least one recess with a rectangular cross-section for realizing the smaller thickness of the middle zone. Preferably, the susceptor comprises two rectangular recesses that are arranged in the extent from the inner zone towards the outer zone behind each other and preferably subdivided by a separation wall. More preferably, the recess is provided on the side of the susceptor that is averted from the side on which the substrate is placeable, i.e. the surface. In this context it is further preferred that the width of the recess parallel to the surface is ≥ 8mm and ≤ 15mm, preferably 11mm.
In another embodiment, the surface comprises an intermediate zone having the same thickness as the inner zone, the intermediate zone comprises a plurality of intermediate heating elements affecting the intermediate zone, the inner zone comprises a plurality of inner heating elements, the middle zone completely surrounds the intermediate zone and the intermediate zone completely surrounds the inner zone, the heating elements and the intermediate heating elements are each provided as heating wires, the inner heating wires each have a greater wire diameter and a greater spacing from each other than the intermediate wires. Such embodiment further allows for a more detailed control of the temperature of the substrate due to a further separation of the inner zone into an intermediate zone located adjacent to the middle zone. This also allows for a further equalizing of the temperature between the different zones and thus in an improved coating quality.
Preferably, all heating elements are provided as heating wires that are in an especially preferred embodiment of the invention provided within the susceptor. In a further embodiment, the heating elements extend around the complete perimeter of the different zones and/or cover the complete respective zone.
In another embodiment it is preferred that the thickness of the middle zone is ≥ 1mm and ≤ 4mm, preferably 2mm, and/or the thickness of the inner zone is ≥ 10mm and ≤ 20mm, preferably 14mm. Providing the susceptor with such thicknesses results in an optimal temperature distribution across the surface of the susceptor and thus in an optimal temperature for the deposition of layers on the so heated substrate.
In an especially preferred embodiment the susceptor comprises a honeycomb-like structure for realising the smaller thickness of the middle zone having recesses provided as pockets and bars between the pockets. Preferably, the width of the pockets in extent parallel to the surface is ≥ 8mm and ≤ 15mm, preferably 11mm. Providing such honeycomb-like structure for realising the middle zone of the susceptor provides a reliable holding of the substrate at elevated temperatures. The bars increase the strength and are preferably introduced with standard susceptor thickness. In other words, providing such honeycomb-like structure allows for a less pronounced temperature gradient between the outer zone and the inner zone. In a further embodiment, the outer zone, the middle zone and/or the inner zone each comprise a rectangular surface shape such that a rectangular substrate is placeable onto the surface, whereby the borders and/or edges of the substrate preferably are arranged on the outer zone.
The object of the invention is further solved by a susceptor arrangement comprising the afore-mentioned susceptor and the substrate, whereby the size of the surface is greater or matches the size of the substrate.
Furthermore, the object of the invention is addressed by a method for manufacturing the afore-mentioned susceptor, whereby the smaller thickness of the middle zone is realized by appending a long hole, a slit and/or a bore to the side of the susceptor that is averted from the side on which the substrate is placeable. Further embodiments and advantages of such method are derivable for the man skilled in the art from the before described susceptor according to the invention.
The object of the invention is furthermore solved by a method for depositing a film on a substrate, comprising the steps of providing the susceptor as described before within a process chamber, supporting the substrate on the surface of the susceptor, providing energy to the inner heating element and to the outer heating element for heating the substrate, and supplying a precursor material into the process chamber so as to deposit the film on the substrate.

Brief Description of Drawings

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
In the drawings:
Fig. 1 shows a susceptor according to prior art in a top view,
Fig. 2 shows a susceptor according to prior art in a side view,
Fig. 3 shows a susceptor according to a preferred embodiment of the invention in a side view,
Fig. 4 shows a part of the susceptor according to the preferred embodiment of the invention in a side view, and
Fig. 5 shows the temperature profile of a substrate treated with the susceptor according to the preferred embodiment of the invention.

Detailed Description of Drawings

Fig. 3 shows a hot plate or susceptor 1 for supporting and thermally controlling a substrate 9 according to a preferred embodiment of the invention in a side view. The susceptor 1 exhibits a substantially flat, plane surface 11 for placing the substrate 9 thereon in thermally conductive contact and has a certain, non-constant thickness 12 measured perpendicularly to the surface 11.
The surface 11 exhibits at least three regions or zones 5, 6, 7 arranged concentrically around each other. The inner zone 5 is an innermost or centre zone exhibiting at least one inner heating element 13 affecting the inner zone 5. An outer or rim zone 7 is completely surrounding the inner zone 5 and includes the area, where during operation of the hot plate 1 the edges and corners 14 of the substrate 9 will be placed.
The middle zone 6 is arranged between the inner zone 5 and the outer zone 7, completely enclosed by the outer zone 7 and completely surrounding the inner zone 5. According to the invention, the middle zone 6 does not exhibit any heating devices actively affecting the substrate 9 arranged in thermal conductive contact with the middle zone 6. Further, the thickness 15 of the hot plate 1 in the middle zone 6 is reduced at least in the predominant part of the middle zone 6 and is lower as the thickness 16 in the outer zone 7 and the thickness 12 in the inner zone 5.
The hot plate 1 can preferably be made from one piece covering the inner zone 5, the middle zone 6 and at least substantial parts of the outer zone 7, preferably the whole outer zone 7. The thickness 15 reduction of the middle zone 6 may be realised by long holes or slits or bores arranged in the plate 1 on the side averted from the substrate 9 forming a recess 23. In an embodiment the hot plate 1 has a substantially rectangular shape for accepting a rectangular substrate 9 such as a thin glass sheet.
In order to locally heat the substrate 9 without affecting the whole temperature pattern of the hot plate 1, localized areas 6 of thin susceptor 1 material are introduced. The inner zone 5 heating wires 13 have a different wire diameter, e.g. 4mm, and spacing as the heater zone wires 17 of an intermediate zone 18, e.g. 3mm. An outer heating element 19 is arranged on the lower side of the susceptor 1 averted from the substrate 9 support surface 11 and held by the susceptor 1 itself.
The significant difference between the prior art susceptor 1 as shown in Fig. 2 and the current solution according to the invention as shown in Fig. 3 is the thinning of the susceptor 1 material between inner zone 5 and the outer zone 7. In this so called heat transfer zone, i.e. the middle zone 6, only 1-4 mm susceptor 1 material thickness 15 contemplated orthogonally to the susceptor 1 surface 11 are remaining, compared to 14mm thickness 12 in the inner zone 5. In the current embodiment the distance 15 between upper and lower surface 11 of the susceptor 1 is only about 2 mm thick. In the embodiment Al is used as susceptor 1 material operating at about 200°C. For operating at those temperatures, a honeycomb-like structure 20 is used for the middle zone 6, as shown in Fig. 4.
Most of the honeycomb structure 20 consists of recesses 23 provided as pockets 21 of 11mm width. In order to increase the strength, bars 22 are introduced with the standard susceptor 1 thickness. In case a smoother transient in temperature is needed between inner zone 5 and outer zone 7 of the susceptor 1 the depth or width of the pockets 21 may be different in the honeycomb structure 20. In the embodiment, the outer pockets 21 are deeper, 2mm susceptor 1 thickness, than the inner pocket 21, 4mm thickness. This allows a less pronounced temperature gradient between outer zone 7 and inner zones 5.
This design clearly allows a decoupling of heating zones 5, 7 as seen from the next table below. There the actual temperatures of the heating zones 5, 7 are equal to the operator setpoints for the hot plate 1. In this example the zone temperatures are also individually controlled like in the prior art example shown above.
Operator set point Actual temperature reading
Inner zone 5 192 °C 192 °C
Intermediate zone 18 195 °C 195 °C
Outer zone 7 204 °C 204 °C
By applying the proposed design, achieving a very uniform substrate 9 temperature distribution is possible. As an example, Fig. 5 shows the temperature profile of a 3 mm glass substrate 9 on a susceptor 1 plate according to the invention. The distance 15 of susceptor’s 1 top surface 11 to bottom surface in the honeycomb structure 20 is 2 mm at its minimum. According to the temperature scan a delta temperature of 3 K is achievable. The temperature settings for the zones 5, 6, 7are indicated below:
Operator set point
Inner zone 1 192 °C
Intermediate zone 18 195 °C
Outer zone 7 204 °C
This hot plate 1 design can be widely used for any hot plate 1 which is used to get good temperature uniformity on a substrate 9. In particular it is usable for large area coating applications such as for manufacturing thin film solar cells.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

Reference Signs List

1 Susceptor
2 Heating wire
3 Heating wire
4 Heating wire
5 First zone, inner zone
6 Second zone, middle, zone
7 Third zone
8 Rim zone, outer zone
9 Substrate
10 Edge bar
11 Surface
12 Thickness of the inner zone
13 Inner heating element
14 Edges and corners
15 Thickness of the middle zone
16 Thickness of the outer zone
17 Intermediate heating element
18 Intermediate zone
19 Outer heating element
20 Honeycomb-like structure
21 Pocket
22 Bar
23 Recess

Claims

A susceptor for supporting a substrate (9) within a vacuum process chamber, comprising a flat surface (11) for placing the substrate (9) thereon such that the substrate (9) is in thermally conductive contact with the surface (11), whereby

the susceptor (1) comprises at least three adjacent zones (5, 6, 8), an outer zone (8), a middle zone (6) and an inner zone (5), the zones (5, 6, 8) arranged concentrically around each other and extending along the surface (11),

the outer zone (8) completely surrounds the middle zone (6) and the middle zone (6) completely surrounds the inner zone (5),

the inner zone (5) comprises at least one inner heating element (13) affecting the inner zone (5),

the outer zone (8) comprises at least one outer heating element (19) affecting the outer zone (8), and

the middle zone (6) exhibits a maximal thickness (15) that is smaller than the minimal thickness (12) of the inner zone (5) and smaller than the minimal thickness (16) of the outer zone (8), each thickness (12, 15, 16) extending perpendicular to the surface (11).
Susceptor (1) according to the previous claim, whereby the minimal thickness (12) of the inner zone (5) is greater than the maximal thickness (16) of the outer zone (8).
Susceptor (1) according to any of the previous claims, whereby the susceptor (1) comprises at least one recess (23) with a rectangular cross-section for realising the smaller thickness (15) of the middle zone (6).
Susceptor (1) according to the previous claim, whereby the width of the recess (23) parallel to the surface (11) is ≥ 8mm and ≤ 15mm, preferably 11mm.
Susceptor (1) according to any of the previous claims, whereby the susceptor (1) comprises an intermediate zone (18) having the same thickness (12) as the inner zone (5), the intermediate zone (18) comprises a plurality of intermediate heating elements (17) affecting the intermediate zone (18), the inner zone (5) comprises a plurality of inner heating elements (13), the middle zone (6) completely surrounds the intermediate zone (18) and the intermediate zone (18) completely surrounds the inner zone (5), the inner heating elements (13) and the intermediate heating elements (17) are each provided as heating wires, the inner heating wires each have a greater wire diameter and a greater spacing from each other than the intermediate wires.
Susceptor (1) according to any of the previous claims, whereby the heating element (13, 17, 19) is provided within the susceptor (1).
Susceptor (1) according to any of the previous claims, whereby the thickness (6) of the middle zone (6) is ≥ 1mm and ≤ 4mm, preferably 2mm, and/or the thickness (12) of the inner zone (5) is ≥ 10mm and ≤ 20mm, preferably 14mm.
Susceptor (1) according to any of the previous claims, whereby the susceptor (1) comprises a honeycomb-like structure (20) for realising the smaller thickness (15) of the middle zone (6) having recesses (23) provided as pockets (21) and bars (22) between the pockets (21).
Susceptor (1) according to the previous claim, whereby the width of the pocket (21) in extent parallel to the surface (11) is ≥ 8mm and ≤ 15mm, preferably 11mm.
Susceptor (1) according to, whereby the outer zone (8), the middle zone (6) and/or the inner zone (5) comprise a rectangular surface (11) shape such that a rectangular substrate (9) is placeable onto the surface (11).
A susceptor (1) arrangement comprising the susceptor (1) according to any of the previous claims and the substrate (9), whereby the size of the surface (11) is greater or matches the size of the substrate (9).
A method for manufacturing a susceptor (1) according to any of the previous claims 1 to 10, whereby the smaller thickness (15) of the middle zone (6) is realized by appending a long hole, a slit and/or a bore to the side of the susceptor (1) that is averted from the side on which the substrate (9) is placeable.
A method for depositing a film on a substrate (9), comprising the steps of

providing the susceptor (1) according to any of the previous claims 1 to 10 within a process chamber,

supporting the substrate (9) on the surface (11) of the susceptor (1),

providing energy to the inner heating element (13) and to the outer heating elements (19) for heating the substrate (9), and

supplying a precursor material into the process chamber so as to deposit the film on the substrate (9).