CN113846375A

CN113846375A - Carrier tray and organic metal vapor deposition equipment

Info

Publication number: CN113846375A
Application number: CN202111120748.1A
Authority: CN
Inventors: 杨翠柏
Original assignee: Shenzhen Zhongkexinchen Technology Co ltd
Current assignee: Shenzhen Zhongke Optical Semiconductor Technology Co ltd
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2021-12-28
Anticipated expiration: 2041-09-24
Also published as: CN113846375B

Abstract

The application provides a sub-carrier disc and an organic metal vapor deposition device. The sub-carrier plate comprises a heat-conducting supporting part. The heat-conductive support portion includes a heat-conductive step. The present application makes local changes to the subcarrier disk. The heat conduction step can compensate the original temperature gradient change of the heated substrate, so that the temperature distribution curve of the heated substrate is changed into a relatively flat temperature distribution curve. The method has the advantage that the adjustment range of the process parameters of epitaxial growth is wider due to the change of the subcarrier disc structure of hardware. In addition, the uniformity of the wafer can be improved, and the cost of the product per unit area can be reduced.

Description

Carrier tray and organic metal vapor deposition equipment

Technical Field

The present disclosure relates to the field of semiconductor technologies, and in particular, to a carrier plate and an organic metal vapor deposition apparatus capable of ensuring temperature uniformity of a substrate after heating in the organic metal vapor deposition apparatus.

Background

Metalorganic Chemical Vapor Deposition (MOCVD) is a key tool for growing compound semiconductor epitaxial structures. The manufacturing cost corresponding to the technology of the equipment derivative development can compete with the traditional technology, and the produced product has competitiveness. Therefore, the development of MOCVD is an ongoing issue. The unit time yield of the MOCVD production equipment is an important basis for evaluating the manufacturing cost. The first commercial MOCVD birth in 1988, which could carry 1 piece of 2 inch substrate and realize the production of components; a 7-piece 2-inch planar reaction chamber (planetar Reactor) that can be used for gallium arsenide (GaAs) and indium phosphide (InP) series materials was introduced in 1992; in 1998, a mass production machine capable of accommodating 5 plates of 6 inches was provided; in recent years, mass production machines of 7 pieces, 6 inches and 8 pieces, 6 inches have been further introduced. The continuous development of vapor deposition technology has led to the mass production of devices such as HBT and the like, and the trend of organometallic vapor deposition machines toward mass production design is inevitable.

The system components of the metal organic vapor deposition machine are mainly divided into the following aspects: reaction Chamber (Reactor Chamber), gas mixing system, electrical system and tail gas processing system.

The core technology of the metal organic vapor deposition machine is mainly designed by a reaction chamber. The main function of the reaction chamber is where various process gases react, and a carrier plate is disposed in the chamber to carry a plurality of sub-carrier plates, and the carrier plate and the sub-carrier plates must be able to effectively absorb the energy provided by the heater to reach the temperature required for film formation growth. The vapor deposition machine is often heated by high power rf electromagnetic wave, infrared lamp, and thermal resistance heater according to the type of heater. Therefore, the material of the carrier plate is mainly composed of graphite, and the temperature of the reaction chamber can cause pyrolysis of the introduced reaction gas, so that the pyrolyzed gas molecules are rearranged and deposited on the compound semiconductor substrate.

However, in the prior art, when MOCVD uses a small sub-carrier plate to perform metal organic chemical vapor deposition, the sub-carrier plate needs to be rotated by the airflow, and the temperature of the edge of the sub-carrier plate is reduced due to the airflow, so that the substrate placed on the carrier plate is easily heated unevenly.

Disclosure of Invention

In view of the foregoing, the present application provides a sub-carrier and an organometallic vapor deposition apparatus. The sub-carrier plate comprises a heat-conducting supporting part. The heat-conductive support portion includes a heat-conductive step. The present application makes local changes to the subcarrier disk. The heat conduction step can compensate the original temperature gradient change of the heated substrate, so that the temperature distribution curve of the heated substrate is changed into a relatively flat temperature distribution curve. The method has the advantage that the adjustment range of the process parameters of epitaxial growth is wider due to the change of the subcarrier disc structure of hardware. In addition, the uniformity of the wafer can be improved, and the cost of the product per unit area can be reduced.

The technical scheme provided by the application is as follows:

a subcarrier disc comprising a thermally conductive support; the heat-conductive support portion includes: a thermally conductive step having a first surface parallel to the subcarrier plate bearing surface and a second surface perpendicular to the subcarrier plate bearing surface.

Further, the subcarrier disc comprises a bearing recess;

the heat conduction support part comprises an inner concave wall continuously arranged along the inner diameter wall surface of the bearing concave part, and the heat conduction step is arranged on the inner concave wall.

Further, the heat conducting step is circumferentially disposed along an inner diameter of the inner recess wall.

Further, the heat conducting steps are arranged at equal intervals along the inner concave wall.

Further, the length of the heat conduction step along the first surface is a transverse width, the length of the heat conduction step along the second surface is a longitudinal depth, and the ratio range of the transverse width to the longitudinal depth is 0.005-500.

Further, the ratio range of the transverse width to the longitudinal depth is 0.05-5, and the longitudinal depth of the heat conduction step is smaller than or equal to that of the inner concave wall.

Further, the heat-conducting supporting part is made of graphite, silicon carbide or a material with the surface of the graphite coated with the silicon carbide.

Further, the heat-conducting supporting part is integrally formed and fixed inside the sub-carrier disc.

Further, the bearing size of the heat conduction supporting part is 1 to 12 inches.

The present application also provides an organometallic vapor deposition apparatus comprising a subcarrier disk as described in any of the above.

In the scheme that this application provided, above-mentioned subcarrier dish can accelerate the base plate heat dissipation for place the base plate on subcarrier dish and be heated more evenly, and can make the temperature distribution curve of the base plate of being heated more even.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic structural diagram of a subcarrier disk according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a partial structure of a subcarrier disk according to an embodiment of the present application;

FIG. 3 is a top view of a position for placing a subcarrier disc according to an embodiment of the present application;

FIG. 4 is a cross-sectional view taken along A-A of FIG. 3 according to one embodiment of the present application;

FIG. 5 is a cross-sectional view of a portion of the design of the subcarrier plate shown in FIG. 4 and enlarged in area B according to an embodiment of the present application;

FIG. 6 is a diagram illustrating a carrier plate structure of an organometallic vapor deposition device and a carrier plate according to an embodiment of the disclosure;

FIG. 7 is a graph comparing the film formation effect of the organometallic vapor deposition device formed by using the sub-carrier plate provided in one embodiment of the present application and a conventional sub-carrier plate.

Reference numerals:

a carrier tray 1; a sub-carrier tray 2; a star-shaped disk 3; a support disc 4; a pulling plate 5; a substrate 6; a temperature compensated air cushion 7; an air cushion 8; the contact surface 2' of the substrate and the subcarrier disc; bottom surface 2 "of the subcarrier tray carrying recess; a heat conductive support portion 21; a thermally conductive step 22.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

The reaction chamber of the organometallic vapor deposition device is mainly where all gases are mixed and reacted. A susceptor is disposed in the reaction chamber for supporting the substrate. The boat must be capable of efficiently absorbing energy supplied from the heater to a temperature required for film formation growth and is not reactive with a reaction gas, and therefore is mostly made of graphite. The heater is heated by infrared lamp or high power RF electromagnetic wave. The reaction cavity is provided with a plurality of channels for cooling water to flow through, and the cooling water can avoid the overheating of the reaction cavity when the film grows.

Carrier gas flows into the system from the uppermost supply end of the system, and the flow of gas in each line into the reaction chamber is controlled via adjustment of a Mass Flow Controller (MFC). The carrier gas is divided into two types, one of which is an organic metal reaction source, and the other is a Hydride (Hydride) gas reaction source. These gases pass through a set of gas switching routers (Run/Vent Switch) before flowing into the reaction chamber to determine whether the gases in the lines reach the reaction chamber or are discharged directly to the exhaust gas line (Vent) at the end of the reaction chamber. The gas flowing into the reaction chamber participates in the reaction to grow into a thin film, and the gas directly discharged into the exhaust gas pipeline at the tail end of the reaction chamber does not participate in the reaction.

The electric control system of the organic metal vapor deposition equipment is a conversion interface between a person and a machine, and the PLC controls the MFC, the PC, the temperature, the pressure, the pneumatic valve, the relay and the like, so that the aim of actually controlling the mechanical action is fulfilled.

The lower end pipeline system of the organic metal vapor deposition equipment is positioned at the rear end of the reaction chamber, unreacted gas, unattached reaction gas and products in the reaction chamber are condensed and separated in a water cooling mode through PT (particle traps), and then the rest gas is discharged to an exhaust system for the next stage treatment through a Throttle valve (Throttle valve) and a pump (pump) of the rear end pipeline, on the one hand, the pressure of the reaction chamber and a gas mixing system can be controlled, and finally, the stability of the process parameters is controlled.

The waste gas system of the organic metal vapor deposition equipment is positioned at the tail end of the system and is responsible for adsorbing and treating all toxic gases passing through the system, and the toxic and harmful waste gases are subjected to reaction, filtration and concentrated treatment in an acid-base neutralization and electrochemical mode by mainly taking sodium hypochlorite as a strong oxidant so as to reduce the pollution to the environment.

With the gradual growth of industrialization, the microwave industry is gradually changed from 4 inches substrates to 6 inches substrates, and new MOCVD equipment is developed to be capable of simultaneously carrying substrates with different sizes. In the situation that the unit price of the wafer is continuously dropping, the uniformity control has become a main factor influencing the yield, and the importance of the unit area cost of effective good products is more and more prominent. For this reason, MOCVD equipment must be adapted to this requirement and adapted accordingly.

When MOCVD uses a small sub-carrier disc to carry out organic metal vapor deposition, the sub-carrier disc needs airflow to drive rotation, the edge of the sub-carrier disc can cause temperature reduction due to the airflow, and then the temperature of the edge is influenced during epitaxial growth, the output area of effective good wafers is reduced, and the cost of effective good wafers is increased.

In view of the above problems, the present application provides a sub-carrier and an organometallic vapor deposition device. The subcarrier dish that provides among this application technical scheme can accelerate the base plate heat dissipation for place the base plate on the subcarrier dish and be heated more evenly, and can make the temperature distribution curve of the base plate of being heated more flat.

Referring to fig. 1, a sub-carrier 2 is provided. The center of the bottom of the sub-carrier disc 2 is provided with a central hole matched with gas to drive a rotating device, so that the sub-carrier disc 2 can rotate in a concentric circle when depositing in an MOCVD machine. Under the action of the air flow, the subcarrier disc 2 can rotate. In particular, the subcarrier disk 2 includes a thermally conductive support 21. The heat conductive support portion 21 includes a heat conductive step 22. The heat conducting step 22 has a first surface parallel to the bearing surface of the subcarrier disk 2 and a second surface perpendicular to the bearing surface of the subcarrier disk 2. During a particular deposition process, a substrate is placed on the thermally conductive step 22.

In this embodiment, the sub-carrier tray 2 includes a heat conductive support portion 21. The heat conductive support portion 21 includes a heat conductive step 22. The present application makes local changes to the subcarrier disk 2. The heat conducting step 22 can compensate the original temperature gradient change of the heated substrate, so that the temperature distribution curve of the heated substrate is changed into a relatively flat temperature distribution curve. The present application allows a wider range of process parameter adjustments for epitaxial growth due to the change in the structure of the subcarrier disk 2 in hardware. In addition, the uniformity of the wafer can be improved, and the cost of the product per unit area can be reduced.

In one embodiment, the subcarrier disc 2 comprises a carrier recess. The heat-conducting support portion 21 includes an inner concave wall continuously provided along an inner diameter wall surface of the bearing recess. The heat conducting step 22 is disposed on the inner concave wall. In one embodiment, the heat-conducting supporting portion 21 is integrally formed and fixed inside the sub-carrier disc 2. In one embodiment, the heat conducting support 21 is part of the subcarrier disk 2, i.e. the heat conducting support 21 is integrally formed with the subcarrier disk 2.

In one embodiment, the thermally conductive step 22 is disposed circumferentially along the inner diameter of the inner recessed wall. I.e. the heat conducting step 22 forms a stepped disc structure inside the subcarrier disc 2. The sub-carrier disc 2 of the present application can change the part of the stepped depth. When the vertical depth of the disc structure is changed, the original temperature gradient change of the heated substrate is compensated to enable the heated substrate to become a relatively flat temperature distribution curve, and the range of adjusting the process parameters of epitaxial growth is wider due to the change of hardware.

Compared with the structure of the subcarrier disc 2 used in the common metal organic vapor deposition, the structure of the subcarrier disc 2 provided by the application is that 1 circular bearing concave part used for bearing a 6-inch prototype substrate is arranged in one subcarrier disc 2, the inner diameter of the bearing concave part is provided with a supporting part used for supporting the substrate, a stepped disc structure is formed on the bottom surface of the concave part, and the subcarrier disc 2 only changes the part with the stepped depth. When the vertical depth of the disk is changed, the original temperature gradient change of the heated substrate is compensated to form a flatter temperature distribution curve.

In another embodiment, the thermally conductive steps 22 are equally spaced along the recessed wall. For example, 4 heat conducting steps 22 may be provided at equal intervals on the inner recess wall. A plurality of the heat conducting steps 22 may be symmetrically or asymmetrically disposed on the inner concave wall.

Referring to fig. 2, in an embodiment, the length of the heat conducting step 22 along the first surface is a transverse width, the length of the heat conducting step 22 along the second surface is a longitudinal depth, and a ratio of the transverse width to the longitudinal depth ranges from 0.005 to 500. In this embodiment, the specific dimensions of the transverse width and the longitudinal depth may be set appropriately according to the size of the boat of the actual organometallic vapor deposition apparatus. For example the longitudinal depth may be set to a size of 20um, 50um, 80um, 100um, 200um, 500um, 1000um, etc.

In one embodiment, the ratio of the transverse width to the longitudinal depth ranges from 0.05 to 5, and the longitudinal depth of the heat conduction step is smaller than or equal to the longitudinal depth of the inner concave wall. In another embodiment, the ratio of the lateral width to the longitudinal depth is in the range of 10 to 100. In another embodiment, the ratio of the lateral width to the longitudinal depth ranges from 1100 to 300. In the embodiment, the proportion range of the transverse width to the longitudinal depth is reasonably set, so that the temperature difference between the edge and the center of the carrying disc can be greatly reduced, the phenomenon of uneven temperature field distribution is reduced, and the yield of products is improved to a certain extent.

In one embodiment, the material of the heat-conducting supporting part is graphite, silicon carbide or a material of which the graphite surface is coated with silicon carbide. Specifically, the heat-conducting support portion may be provided as a graphite material. The heat-conducting supporting part can also be made of silicon carbide material. The heat conducting support part can also be arranged in a way that the graphite surface is coated with a silicon carbide material.

In one embodiment, the thermally conductive support has a load bearing dimension of 1 inch to 12 inches. Specifically, the carrying size of the subcarrier disc means that the subcarrier disc can carry substrates with different sizes. In this embodiment, the sub-carrier tray may carry 1 inch substrate, 2 inch substrate, 4 inch substrate, 6 inch substrate, 8 inch substrate, and 12 inch substrate. The sub-carrier plate can be applied to a mass production machine station which can hold 5 pieces of 6 inches in the organic metal vapor deposition equipment. A7-piece 6-inch and 8-piece 6-inch mass production machine can be accommodated in the metal organic vapor deposition equipment.

In an embodiment, please refer to fig. 3-7, which illustrate the application of the sub-carrier plate 2 to the organometallic vapor deposition device. Fig. 3 is a top view of a placement position of the subcarrier disc 2 according to an embodiment of the present application. Fig. 4 is a sectional view taken along a-a in fig. 3. Fig. 5 is a cross-sectional view of a partial design of the subcarrier disk after enlargement of area B in fig. 4. FIG. 6 is a diagram illustrating a carrier plate structure of an organometallic vapor deposition device and a position relationship of the carrier plate according to an embodiment of the disclosure. FIG. 7 is a graph comparing the film formation effect of the organometallic vapor deposition device formed by using the sub-carrier plate provided by the present application and a conventional sub-carrier plate.

The number of the sub-carriers of the organometallic vapor deposition apparatus may be set to n. In fig. 3 7 subcarrier disks are provided. The temperature compensated air cushions 7 and 8 in fig. 4 were formed during the specific experiments. Fig. 5 is a sectional structure view of the subcarrier disk 2 according to the present application. In fig. 5, 2 denotes a sub-carrier disc, and 2' denotes a contact surface (partially floating, only edge contact) of the substrate 6 and the sub-carrier disc 2. 2 "represents the pit bottom of the subcarrier disc 2. The groove in fig. 6 is a structural feature of a graphite large disc (the carrier disc 1 in fig. 3 and 4), and when gas enters, an annular gas flow is formed, and the annular gas flow rubs with the bottom surface of the subcarrier disc 2 to drive the subcarrier disc 2 to rotate. X in FIG. 6_SRepresents the gap (G) between the outer circle of the sub-carrier plate 2 and the graphite carrier plate 1_ap)，A_BRepresents the diameter of the pits of said sub-carrier disc 2, X_BRepresenting a gap G between the sub-carrier plate 2 and the bottom surface of the graphite carrier plate 1_ap，A_SRepresenting the height (thickness) of the subcarrier disc 2. As can be seen from Δ T ([ delta ] Q · X)/(k · a · Δ T), the temperature difference (Δ T) is proportional to the distance (X) and inversely proportional to the heat receiving area (a). Fig. 6 shows the temperature effect of the edge of the subcarrier disk 2, and it can be seen that when the distance between the edge and the center of the subcarrier disk 2 is larger, the temperature is more uneven, which has a great influence on the yield of the product.

During vapor deposition, the sub-carrier plate 2 carries the substrate 6, and the rotating gas (the rotating gas may be referred to as a gas cushion 8) is formed by introducing hydrogen into the carrier plate 1, so as to drive the sub-carrier plate 2 to rotate. After the hydrogen is carried, the hydrogen is discharged into the reaction chamber through the horizontal space between the sub-carrier plate 2 and the carrier plate 1. During the transfer of the fast flowing hydrogen to the reaction chamber, part of the energy is also taken away from the edge of the subcarrier disk 2, which causes the temperature gradient of the subcarrier disk 2 to change, so that a stepped annular bearing (called a heat conducting support) is used. The heat-conducting support part is located at the bottom of the concave part of the subcarrier disk 2, and a layer of temperature compensation air cushion 7 is added between the substrate 6 and the subcarrier disk 2 due to the heat-conducting support part (stepped annular bearing part). The size of the temperature compensation air cushion 7 is controlled by adjusting the size of the vertical depth (longitudinal depth in fig. 2) of the heat-conducting supporting part, so that the degree of heating of the center of the wafer can be reduced, and the temperature gradient change of the substrate 6 can be compensated. The horizontal width (lateral width in fig. 2) of the heat-conducting support portion in this embodiment is determined by the width of the substrate 6 required to compensate for the edge effect.

In the specific embodiment, the proportion relation between the longitudinal depth and the transverse width of the annular bearing part of the heat-conducting supporting part (the stepped annular bearing part) is designed, and is a scientific conclusion obtained through a plurality of experiments of the inventor. The inventors used GaAs substrates placed into the thermally conductive supports at various annular depths. Further sending the sub-carrier disc carrying the GaAs substrate into the reaction cavity, heating to 670 ℃, and introducing TMGa and AsH₃And growing a buffer layer. After the growth of the buffer layer is finished, the temperature is continuously raised to 750 ℃, and then TMGa, TMAl, TMIn and PH are introduced₃Epitaxially growing Al_xIn_1-xP/Ga_xIn_1-xP Double heterojunction (Double heterojunction-structure). And finally, testing the grown epitaxial wafer by using an X-Ray double-crystal diffractometer (X-Ray Diffraction) and a laser spectrometer (Photo-Luminescence). The composition distribution chart of the test data is calculated, as shown in fig. 7. Fig. 7 reflects the variation in film thickness uniformity in the radial direction of the substrate. The better the uniformity of the epitaxial growth film, the smaller the standard deviation. The data curves in fig. 7 respectively show that when the ratio of the longitudinal depth to the lateral width of the annular bearing portion of the heat-conducting supporting portion 21 (stepped annular bearing portion) is adjusted, the difference of the uniformity of the epitaxial growth film is obtained (reflected by the standard deviation in fig. 7) when the longitudinal depth of the heat-conducting step 22 is not conventionally set, the longitudinal depth of the heat-conducting step 22 is set to be 50um, the longitudinal depth of the heat-conducting step 22 is set to be 100um, and the longitudinal depth of the heat-conducting step 22 is set to be 200 um. The data results in fig. 7 show that when the ratio of the longitudinal depth to the lateral width of the annular bearing part of the heat-conducting support part (stepped annular bearing part) is changed, the temperature difference between the edge and the center of the carrier plate can be greatly reducedThe phenomenon of uneven temperature field distribution is reduced, and the yield of products is improved to a certain extent.

Therefore, the application proposes to provide a heat-conducting support part on the subcarrier plate. The heat-conductive support portion includes a heat-conductive step. And further setting the ratio range of the transverse width to the longitudinal depth to be 0.005-500. The present application makes local changes to the subcarrier disk. The heat conduction step can compensate the original temperature gradient change of the heated substrate, so that the temperature distribution curve of the heated substrate is changed into a relatively flat temperature distribution curve. The method has the advantage that the adjustment range of the process parameters of epitaxial growth is wider due to the change of the subcarrier disc structure of hardware. In addition, the uniformity of the wafer can be improved, and the cost of the product per unit area can be reduced.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A subcarrier disc, wherein the subcarrier disc comprises a thermally conductive support portion;

the heat-conductive support portion includes: a thermally conductive step having a first surface parallel to the subcarrier plate bearing surface and a second surface perpendicular to the subcarrier plate bearing surface.

2. The subcarrier disc of claim 1, wherein the subcarrier disc comprises a bearing recess;

3. The subcarrier disc of claim 2, wherein the thermally conductive step is disposed circumferentially along an inner diameter of the inner recess wall.

4. The subcarrier disc of claim 2, wherein the thermally conductive steps are equally spaced along the interior recess wall.

5. The subcarrier disc of claim 3 or 4, wherein the heat conducting step has a transverse width along a length of the first surface and a longitudinal depth along a length of the second surface, and a ratio of the transverse width to the longitudinal depth is in a range of 0.005-500.

6. The subcarrier disc of claim 5, wherein a ratio of the transverse width to the longitudinal depth ranges from 0.05 to 5, and a longitudinal depth of the heat conducting step is less than or equal to a longitudinal depth of the inner concave wall.

7. The subcarrier disc of claim 6, wherein the thermally conductive support is made of graphite, silicon carbide or a material with a graphite surface coated with silicon carbide.

8. The subcarrier disc of claim 7, wherein the thermally conductive support portion is integrally formed and fixed to an interior of the subcarrier disc.

9. The subcarrier tray of claim 2, wherein the thermally conductive support portion has a load bearing dimension of 1 inch to 12 inches.

10. An organometallic vapor deposition apparatus comprising the sub-carrier tray described in any of 1 to 9 above.