Multi-disk chemical vapor deposition system with cross-flow gas injection.

Abstract

1. A multi-wafer metal organic chemical vapor deposition system comprising: a reaction chamber in which adjacent wafers disposed within the system rotate about their own axes and having an exhaust system including a peripheral port; a multi-wafer carrier comprising a wafer carrier body and a plurality of wafer carrier disks supported within the wafer carrier body, wherein adjacent wafer carrier disks of the plurality of wafer carrier disks are configured and the wafer carrier body is configured to rotate at different speeds; a multi-zone injection block disposed above the wafer carrier body; a central gas port disposed in a center of the wafer carrier body, the central gas port being configurable as a gas exhaust or gas injection port; and a multi-zone susceptor heater assembly disposed below the multi-wafer carrier.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Patent Application No. 63 / 428,250, filed November 28, 2022, and U.S. Patent Application No. 63 / 428,261, filed November 28, 2022, each of which is incorporated by reference herein in its entirety.

[0002] The present technology relates generally to semiconductor manufacturing technologies, and more particularly to chemical vapor deposition processes and related systems that have the high performance standards of single-wafer reactors, with productivity metrics for large-volume, multi-wafer batch reactors. More specifically, the present disclosure lists and illustrates chemical vapor deposition processes and related systems configured to avoid or substantially minimize parasitic ceiling deposition, thereby eliminating or reducing the need for in-situ cleaning, improving component life, increasing growth rates, improving gas usage efficiency, and widening the process window for deposition uniformity at the wafer. Eliminating or reducing in-situ cleaning shortens cycle times and extends preventative maintenance cycles. [Background technology]

[0003] Certain processes for manufacturing semiconductors can require complex processes for growing epitaxial layers to create multilayer semiconductor structures for use in manufacturing high-performance devices such as light-emitting diodes (LEDs), laser diodes, photodetectors, power electronics, and field-effect transistors. In this process, the epitaxial layers are grown via a common process called chemical vapor deposition (CVD). One type of CVD process is called metal-organic chemical vapor deposition (MOCVD). In MOCVD, reactive gases are introduced into a reactor chamber in a controlled environment, allowing the reactor gases to react on a substrate (commonly called a wafer) and grow a thin epitaxial layer.

[0004] During epitaxial layer growth, several process parameters, such as temperature, pressure, and gas flow rates, are controlled to achieve the desired epitaxial layer quality. Different layers are grown using different materials and process parameters. For example, devices formed from compound semiconductors, such as III-V or IV-IV semiconductors, are typically formed by growing a series of distinct layers. In this process, the wafer is exposed to a combination of reactive gases, which typically include an alkyl source containing a Group III metal, such as aluminum (Al), gallium (Ga), indium (In), and combinations thereof, and a metal-organic compound, such as NH3, AsH3, PH3, or an Sb organometallic, typically in the form of nitrogen (N), phosphorus (P), arsenic (As), or antimony (Sb). In the case of IV-IV, at least two elements of silicon (Si), carbon (C), and germanium (Ge) are typically used as hydrides, such as SiH4, Si2H6C2H4, C3H8, GeH4, or chloride-based gases such as SiH2Cl2 and SiHCl3. Generally, the alkyl and hydride sources are combined with a carrier gas, such as nitrogen (N2), argon (Ar), and hydrogen (H2), or a mixture of H2 with N2 or Ar, which participates less in the reaction. In these processes, the alkyl and hydride sources flow over the surface of the wafer and react with each other to form compounds of the general formula In X Ga Y Al Z N A As B P C Sb D where x+y+z is equal to about 1, A+B+C+D is equal to about 1, and X, Y, Z, A, B, C, and D can each be between 0 and 1. In other processes, commonly referred to as "halide" or "chloride" processes, the Group III metal source is the metal or a volatile halide of the metal, most commonly a chloride such as GaCl. In still other processes, bismuth is used in place of some or all of the other Group III metals.

[0005] Suitable substrates for the reaction may be in the form of wafers having metallic, semiconducting, and / or insulating properties. In some processes, the wafers may be formed from sapphire, aluminum oxide, silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), indium phosphide (InP), indium arsenide (InAs), gallium phosphide (GaP), aluminum nitride (AIN), silicon dioxide (SiO2), etc.

[0006] In a CVD process chamber based on a spinning disk reactor architecture, one or more wafers are placed inside a rapidly rotating carousel, commonly referred to as a "wafer carrier," so that the top surface of each wafer is exposed and uniformly exposed to the atmosphere within the reactor chamber for deposition of semiconductor materials. The wafer carrier is typically machined from a highly thermally conductive material such as graphite and is often coated with a protective layer of a material such as silicon carbide or tantalum carbide. Each wafer carrier has a series of circular depressions or pockets on its top surface into which individual wafers are placed. The wafer carrier typically rotates at a rotational speed on the order of about 50 to 1500 RPM or more. As the wafer carrier rotates, reactive gases are introduced into the chamber from a gas distribution device located upstream of the wafer carrier. The flowing gases preferably flow downstream toward the wafer carrier and wafers in a laminar manner.

[0007] During the CVD process, the wafer carrier is often maintained at a desired elevated temperature by a heating element positioned below the wafer carrier. Heat is then transferred from the heating element to the bottom surface of the wafer carrier and flows upward through the wafer carrier to the wafer or wafers. Depending on the process, the wafer carrier temperature is maintained on the order of approximately 550–1200°C for GaN-based films. Higher temperatures (e.g., up to approximately 1450°C) are used for the growth of AlN-based films, while lower temperatures (e.g., down to approximately 350°C) are used for the growth of AsP films. For some materials, such as SiC, temperatures of 1600–1700°C are required. Other temperature ranges are suitable for other materials, such as SiC, Si, and SiGe, or 2D materials such as graphene, as well as sulfides or selenides of tungsten and molybdenum. However, reactive gases are introduced into the chamber by a gas distribution device at much lower temperatures, typically around 200°C or below, to suppress premature reaction of the gases.

[0008] As the reactive gas approaches the rotating wafer carrier, its temperature increases substantially, and the viscous drag of the rotating wafer carrier causes the gas to rotate about the axis of the wafer carrier, causing the gas to flow outward about the axis toward the periphery of the wafer carrier and across an interface region near the surface of the wafer carrier. Depending on the reactive gas used in the process, thermal decomposition may occur in or near the interface region at an intermediate temperature between the gas distribution device and the wafer carrier. This thermal decomposition produces intermediate species that promote the growth of crystalline structures. Unconsumed gas continues to flow toward the periphery and beyond the outer edge of the carrier, where it is removed from the process chamber through one or more exhaust ports located below the wafer carrier.

[0009] Currently, there are two broad categories of process chambers based on the rotating disk reactor concept: (1) high-performance single-wafer reactors, such as the PROPEL™ GaN MOCVD system manufactured by Veeco Instruments Inc. of Plainview, New York, capable of depositing high-quality GaN films on 200 mm (8 inch) and 300 mm (12 inch) silicon wafers for applications such as power, RF, and photonics, and (2) high-volume multi-wafer reactors, such as the TurboDisc EPIK® family of MOCVD systems, also manufactured by Veeco Instruments Inc. of Plainview, New York, designed for mass production of mini- and micro-LEDs, typically on 100 mm (4 inch) or 150 mm (6 inch) silicon wafers, and related product families called the K475i and Lumina for the growth of AsP-based films. While such systems have proven to perform exceptionally well, there is a continuing desire to manufacture exceptionally efficient process chambers that have higher equipment efficiency (ratio of throughput to capital investment), smaller footprints, and lower associated operating costs, while maintaining the high quality deposition standards required for certain GaN film applications, for example.

[0010] In particular, some emerging applications (such as micro LEDs) impose very stringent requirements on wavelength and film thickness uniformity, while also needing to achieve very low defect levels. For example, for blue micro LEDs, the allowable wavelength range is 2 nm, the thickness variation range is 4%, and the allowable defect level for defects larger than 1 μm is 0.1 / cm. 2To achieve these stringent requirements, uniformity must be achieved simultaneously for several parameters across the substrate. This includes gas flow rate, boundary layer thickness, gas temperature, and wafer temperature. Because the substrate bends significantly during growth and the bow varies during various growth stages, dynamic temperature control of a pocket under the wafer is necessary to ensure a uniform wafer temperature throughout all growth stages. Single-wafer reactors, in which the substrate rotates on its axis and the gas flow directed toward the substrate encounters the wafer before flowing on a carrier, possess these attributes; however, until now, it has not been possible to consistently achieve these same attributes in conventional multi-disk batch reactors. The present disclosure addresses this and other concerns. Summary of the Invention

[0011] The disclosed technology generally relates to chemical vapor deposition processing systems and related methods that achieve the high-performance deposition standards of single-wafer reactors with the productivity metrics of large-volume, multi-wafer batch reactors. In embodiments, the disclosure includes a reactor capable of processing multiple rotating disks, where each disk emulates a single-wafer reactor integrated into a batch reactor, and common gas distribution systems, injectors, heater assemblies, in-situ measurements, chamber bodies, exhaust, and rotation mechanisms may be shared between the disks. To achieve a high degree of consistency in epitaxial growth, in some embodiments, for example, the disks can rotate in a circular, elliptical, racetrack, or any other closed path within the chamber, so that each disk experiences a nearly identical time-averaged process environment. Accordingly, embodiments of the disclosure describe a more compact (e.g., smaller footprint) chemical vapor deposition system with lower operating costs, higher equipment efficiency, and without compromising deposition quality.

[0012] One embodiment of the present disclosure provides a multi-wafer metal organic chemical vapor deposition system, the system including: a reaction chamber having an exhaust system in which adjacent wafers disposed within the system rotate about their own axis; a multi-wafer carrier including a wafer carrier body and a plurality of wafer carrier disks supported within the wafer carrier body; an injection block having at least one injection zone disposed above the multi-wafer carrier; a central gas injection port disposed at the center of the multi-wafer carrier; and a heater assembly disposed below the multi-wafer carrier.

[0013] In one embodiment, a multi-wafer metal organic chemical vapor deposition system is disclosed in which adjacent wafers disposed within the system rotate about their own axes. A gas injector is provided for injecting gas into the reaction chamber. The system has a movable cover plate configured to act as a barrier to deposition gases to minimize growth rate non-uniformities caused around the edge of the wafer. The movable cover plate moves between a lowered home position that allows loading and unloading of a wafer carrier body and a raised operating position that includes an active deposition position.

[0014] The system can include a lift mechanism for moving the cover plate between a lowered home position and an elevated operating position, the lift mechanism configured to allow rotation of the multi-wafer carrier. In one embodiment, the lift mechanism can include a plurality of lift pins configured to pass through corresponding through-holes in the multi-wafer carrier and drive the cover plate from the lowered home position to the elevated operating position, allowing the cover plate to be lowered. The lift mechanism is rotatable to accommodate rotation of the wafer carrier. Furthermore, the lift mechanism includes a motor configured to controllably rotate the cover plate between a plurality of indexed positions. Alternatively, if a movable central gas injector is used, the cover plate can be moved up and down by movement of the central gas injector.

[0015] In another embodiment, the gas injector includes a central gas injector movable between a raised operating position and a lowered home position, and movement of the central gas injector between the lowered home position and the raised operating position translates into movement of the cover plate between the lowered home position and the raised operating position.

[0016] Additionally, a water-cooled plate can be positioned above the cover plate for thermal conditioning of the cover plate.

[0017] The above summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure, although the following figures and detailed description more particularly exemplify these embodiments.

[0018] The present disclosure may be more fully understood in consideration of the following detailed description of various embodiments thereof in connection with the accompanying drawings, in which:

[0019] [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view of a precision multi-wafer metal organic chemical vapor deposition system with cross-flow gas injection. [Figure 2] FIG. 2 is a cross-sectional view of a portion of the system of FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of another portion of the system of FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view of the system of FIG. 1, showing the movable central gas injector in a raised position. [Figure 5] FIG. 2 is a top view of a split coil assembly for the susceptor of the system of FIG. 1. [Figure 6] FIG. 1 is a top view of the susceptor and the location of the satellites and susceptor pins. [Figure 7] FIG. 2 is a top view of the ceiling coil of the system of FIG. 1. [Figure 8] 1 is a cross-sectional view of a gas-powered rotary drive. [Figure 9] FIG. 1 is a cross-sectional view of a multi-wafer metal organic chemical vapor deposition system with cross-flow gas injection and multi-zone resistive heating arrangement for GaN applications. [Figure 10] FIG. 1 is a cross-sectional view of an automated wafer loading and unloading mechanism showing the central gas injector in the raised (in-process) position, according to one embodiment. [Figure 11] FIG. 11 is a cross-sectional view of the mechanism of FIG. 10 in the loading and unloading position with the central gas injector in the lowered position. [Figure 12] FIG. 10 is a cross-sectional view of a loading and unloading mechanism utilizing a Bernoulli gripper. [Figure 13] 1 is a cross-sectional view of an automated wafer loading and unloading mechanism including lift pins shown in a lowered position, according to one embodiment. [Figure 14] FIG. 14 is a cross-sectional view of the mechanism of FIG. 13 with the lift pins in the raised position. [Figure 15] FIG. 10 is a cross-sectional view of an automated wafer loading and unloading mechanism according to another embodiment, showing the central gas injector in the raised (in-process) position. [Figure 16] FIG. 16 is a cross-sectional view of the arrangement of FIG. 15 with the central gas injector in the lowered position. [Figure 17] 1 is a cross-sectional view of an automated wafer loading and unloading mechanism including lift pins shown in a lowered position, according to one embodiment. [Figure 18] FIG. 18 is a cross-sectional view of the mechanism of FIG. 17 with the lift pins in the raised position. [Figure 19] FIG. 2 is a top view of a separated wafer carrier. [Figure 20] FIG. 1 is a cross-sectional view showing a section of an isolated wafer carrier in a raised position. [Figure 21] FIG. 10 is a cross-sectional view of a rotatable platform and a satellite ring driven by a common motor through separate gears to achieve a rotational speed differential between the rotatable platform and the satellite ring. [Figure 22]22 is an enlarged cross-sectional view of the satellite of FIG. 21, consisting of a disk with a hub at the bottom. [Figure 23] FIG. 1 is a cross-sectional schematic diagram showing a centrally located multi-zone injector including at least two separate zones for distribution of reactive gases into a reaction chamber in a cross-flow direction, according to an embodiment of the present disclosure. [Figure 24A] FIG. 1 is a cross-sectional schematic diagram illustrating a multi-wafer metal organic chemical vapor deposition system including a centrally located injector configured to selectively lift a movable cover plate, with the cover plate in a home position, according to an embodiment of the present disclosure. [Figure 24B] 24B illustrates the multi-wafer metal organic chemical vapor deposition system of FIG. 24A with the cover plate in the active position, according to an embodiment of the present disclosure. [Figure 25] FIG. 10 is a partial cross-sectional view showing a cooling or thermal conditioning mechanism for the cover plate. [Figure 26] 1 is a partial cross-sectional view illustrating a substrate wafer residing within a pocket defined in an individual wafer support disk of a wafer carrier according to an embodiment of the present disclosure. [Figure 27] FIG. 1 is a cross-sectional view of a precision multi-wafer metal organic chemical vapor deposition system with cross-flow gas injection according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] While the embodiments of the present disclosure are susceptible to various modifications and alternative forms, specific subject matter shown by way of example in the drawings will be described in detail. It should be understood, however, that it is not intended to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.

[0022] As wafer sizes for III-V epitaxial growth increase from 150 mm diameter wafers to larger diameter wafers, such as 200 mm and 300 mm diameter wafers, consumer preference is generally trending toward single-wafer reactors, such as the PROPEL™ GaN MOCVD system, due to their superior uniformity and process control. An exemplary embodiment of the PROPEL™ GaN MOCVD system is disclosed in U.S. Patent Application Publication No. 2017 / 0067163, the contents of which are incorporated herein by reference. Advantages of single-wafer reactors include rotational averaging for improved deposition uniformity without leading and / or trailing edge effects, low centripetal forces on the wafer, and a wide process window (e.g., 25 Torr, 1450°C, 3000 RPM, etc.). Single-wafer reactors are also more readily adaptable to hot-wire chemical vapor deposition (alternatively referred to as "catalytic chemical vapor deposition"), a deposition method in which precursor gases are catalytically dissociated on a resistively heated filament.

[0023] However, single-wafer reactors are generally considered less cost-effective than multi-wafer batch reactors, especially for 150 mm and 200 mm wafers in certain applications. In particular, batch reactors, such as the TurboDisc EPIK® family of MOCVD systems, typically have higher footprint efficiency, higher capital expenditure efficiency, and an overall lower cost of ownership. Examples of the TurboDisc EPIK® family of MOCVD systems are disclosed in U.S. Patent Application Publication Nos. 2007 / 0186853 and 2012 / 0040097, as well as U.S. Patent Nos. 6,492,625, 6,506,252, 6,902,623, 8,021,487, and 8,092,599, the contents of which are incorporated herein by reference. For 300 mm diameter wafers, the metric differences between single-wafer and batch reactors are relatively small, making single-wafer reactors the preferred choice. However, for wafers less than 300 mm in diameter (e.g., 200 mm and 150 mm diameter wafers), higher capacity batch reactors are the preferred choice. Unfortunately, to date, batch reactors have not been able to meet the precision deposition requirements of all applications.

[0024] 1-2, a precision multi-wafer metal organic chemical vapor deposition system 200 configured to achieve the performance of a single wafer reactor with the productivity and efficiency of a multi-disk batch reactor is shown in accordance with an embodiment of the present disclosure. In an embodiment, the precision multi-wafer metal organic chemical vapor deposition system 200 can include a reaction chamber 201 (sometimes referred to herein as a "process chamber" or "reactor") configured to define a process environment space, and an injector 102 (alternatively referred to herein as a "gas distribution device") can be disposed within the environment space.

[0025] The end of the reaction chamber 201 where the injector 102 of FIGS. 1 and 2 is located may be referred to as the "top" end of the reaction chamber 201. This end of the chamber is typically, but not necessarily, located at the top of the chamber in a common gravity reference frame. Thus, whether aligned with gravity, upward and downward directions, as used herein, refer to a direction away from the injector 102, while upward refers to a direction within the chamber toward the injector 102 gas inlet manifold. Similarly, the "top" and "bottom" of elements may be described herein with reference to the reaction chamber 201 and injector 102 reference frames. Construction of an inverted system 200 in which process gas flows upward from the bottom of the reaction chamber 201 is also contemplated. The injector 102 may be centrally located within the process chamber (as shown in FIGS. 1 and 27) to affect a substantially horizontal or crossflow of reactive gases over a substrate disposed within the reaction chamber 201.

[0026] 1-7 disclose a precision multi-wafer metal organic chemical vapor deposition system 200, according to one embodiment. System 200 includes a reaction chamber 201. System 200 can be considered to include an upper (ceiling or lid) region and a lower (substrate) region. The upper region includes the ceiling of reaction chamber 201, and the lower region includes a wafer carrier.

[0027] There are also load ports 110 along the sidewalls of the system for loading and unloading wafer carriers, which are described in more detail below.

[0028] The reaction chamber 201 comprises a hot-wall reactor and includes heated sidewalls that are water-cooled as a result of the sidewalls having an internal chamber through which water circulates. This mechanism allows for control of the sidewall temperature of the reaction chamber 201.

[0029] Heated and purged ceiling In system 200, both ceilings of reaction chamber 201 are heated and include a showerhead architecture for injecting purge gas into reaction chamber 201.

[0030] Atop the reaction chamber 201 is a lid, which is defined by a top wall 210 and includes water cooling for temperature control. The top wall 210 also includes a through port that passes completely through the top wall 210, as well as other openings for receiving associated equipment as described herein. Thus, the top wall 210 may include an internal chamber (annular space) through which water circulates. The top wall 210 includes an interior surface or surfaces 212. Thus, the lid is water cooled.

[0031] A ceiling heater assembly 220 is provided and is disposed between the top wall 210 and the hollow interior of the reaction chamber 201, which contains a wafer carrier and is disposed along an inner surface 212 of the top wall 210. The ceiling heater assembly 220 may include one or more support brackets 230 coupled to the inner surface 212. Much like the top wall 210, the support brackets 230 include through ports that align with ports formed through the top wall 210. The one or more support brackets 230 may be formed from quartz or other suitable material. One or more support clamps 235 are provided and coupled to the one or more support brackets 230.

[0032] The ceiling heater assembly 220 is spaced apart from the top wall 210 and includes a diffusion barrier 240 disposed parallel to the top wall 210. The diffusion barrier 240 is formed from a suitable material (e.g., quartz) that can withstand the operating temperatures of the reaction chamber 201. The diffusion barrier 240 prevents diffusion of gases from the reaction chamber 201 to the ceiling and the ceiling heater assembly 220.

[0033] Between the diffusion barrier 240 and the support bracket 230 is a heater cavity 250, which includes an open space where the active components of the ceiling heater are located. The main active components of the ceiling heater include a ceiling heater coil 260, which may be a water-cooled RF coil. The RF coil may be made of copper and have a hollow center through which cooling water flows. FIG. 7 shows one exemplary RF ceiling heater coil 260 having a concentric circular shape. A stabilizing rod 261 for stabilizing the coil itself is shown along FIG. 7. As shown in FIG. 1, the ceiling heater coil 260 is attached to one or more support brackets 230, and a (quartz) coil support / pedestal 270 is provided for suspending the RF ceiling heater coil 260.

[0034] As part of the cooling circuit, there are one or more water inlets 280 that supply water to the RF ceiling heater coil 260 and one or more water outlets 290 that draw water from the RF ceiling heater coil 260. The water inlet(s) 280 and the water outlet(s) 290 are in fluid communication with the hollow interior of the ceiling heater coil 260 through which water flows.

[0035] The ceiling heater assembly 220 is intended to heat the ceiling of the system 200. More specifically, in the exemplary embodiment described herein, the ceiling heater assembly 220 operates at a higher temperature than the heater (described herein) that heats the susceptor.

[0036] The ceiling of the system 200 is formed from an upper ceiling plate 300 and a lower ceiling plate 310 spaced apart from the upper ceiling plate 300. The upper ceiling plate 300 is disposed adjacent to the diffusion barrier 240, and an open space 315 is formed between the upper ceiling plate 300 and the lower ceiling plate 310. This open space 315 can be considered a gas manifold that distributes gases and allows them to be injected into the reaction chamber 201. Thus, the open space 315 has an annular shape.

[0037] The upper ceiling plate 300 is configured and intended to absorb energy from the RF heater (RF ceiling heater coil 260).

[0038] The upper ceiling plate 300 includes ports (openings) that align with at least a portion of the ports through the diffusion barrier 240 and allow equipment such as temperature measurement equipment and gas injector devices / nozzles to pass through. The lower ceiling plate 310 includes a plurality of showerhead holes 311 ( FIG. 2 ) that communicate directly into the reaction chamber 201. Gases injected into the open space 315 flow through the open space 315 and exit through the showerhead holes 311. The showerhead holes 311 can be formed in different patterns to enable uniform distribution of gases into the reaction chamber 201.

[0039] As described herein, the showerhead design allows for ceiling purging, and more specifically, the ceiling showerhead allows for injection of carrier gases (H, N, Ar, or combinations thereof) and, in some applications, etching gases (e.g., HCl, Cl, TBCl, etc.).

[0040] The ceiling of system 200 is attached to the lid using a suitable mounting structure. For example, the ceiling heater assembly can be attached to the lid using an outer support ring 320 and an outer middle ring 330. The outer middle ring 330 is disposed radially inward from the outer support ring 320. The rings 320, 330 can be formed of quartz.

[0041] The ceiling of system 200 is actively heated by a heat source separate from the susceptor heating system. According to one aspect of the present system 200, the operating temperature of the ceiling heater assembly 220 is different from the bottom (susceptor) heater assembly that heats the wafer carrier. This reduces the temperature gradient between the ceiling and the susceptor holding the substrate, thereby reducing convection currents due to the temperature gradient toward the ceiling.

[0042] For example, the operating temperature of the ceiling heater assembly 220 is higher than the operating temperature of the bottom (susceptor) heater assembly. For example, the operating temperature of the ceiling heater assembly 220 can be 600°C to 1200°C, or 700°C to 1100°C, or 1600°C to 1800°C, while the operating temperature of the bottom heater assembly is 600°C to 900°C, or 700°C to 1400°C, or 1500°C to 1700°C.

[0043] Gas purging occurs from introducing gases into the reaction chamber 201 through the ceiling (showerhead holes 311). In one embodiment, one or more showerhead gas modules 315 may be provided along the lid, passing through ports formed through the top wall and diffusion barrier, and through ports formed in the upper ceiling plate 300. In this manner, one or more gases, such as a carrier gas such as H2 / Ar and / or an etching gas such as HCl, are injected directly into the open space 315 and then exit through the showerhead holes 311 and enter the reaction chamber 201 according to a desired predetermined pattern.

[0044] Additional measurement equipment may be included and located along the lid. For example, a ceiling pyrometer 317 with a light pipe may be provided and used to monitor the temperature of the ceiling. The ceiling pyrometer 317 passes through the top wall and diffusion barrier, with the distal end of the ceiling pyrometer 317 positioned in the open space between the upper ceiling plate 300 and the diffusion barrier. Additionally, a pyrometer and viewport 319 may be provided to take measurements and obtain a direct view of the wafer (substrate).

[0045] SiC application For SiC epitaxy, the ceiling temperature rises to 1600-1800°C due to heating by the RF pancake coil (RF ceiling heater coil 260). The contact temperature with the quartz should not exceed 1200°C. Therefore, at least two intermediate rings 330 are located between the ceiling and the quartz support to lower the temperature and further reduce thermal stress. For SiC applications, the choice of ceiling and susceptor material becomes more restrictive due to the high temperatures and interactions with the carrier and process gases. For SiC epitaxy, only graphite or solid SiC with a TaC or SiC coating exists. The limitation of the SiC coating is its removal by sublimation when in close proximity to a cooler surface.

[0046] GaN Applications For GaN applications, the ceiling temperature rises to 700°C–1100°C due to heating by the RF pancake coil (RF ceiling heater coil 260). The choice of material for the ceiling and susceptor is not particularly critical, but it must be protected from high-temperature ammonia, requiring a protective coating of graphite. The preferred coating is SiC, but TaC or pyrolytic boron nitride can alternatively be used as coatings. Solid SiC can also be used for some components, such as the cover plate, satellites, and satellite ring.

[0047] The susceptor can also be heated to 700° C. and 1400° C. by providing limited heating using filaments preferably made of W or Re. Resistive heating provides multi-zone temperature control that is not possible with RF heating.

[0048] GaAs / InP applications For GaAs / InP applications, using a pancake coil (RF ceiling heater coil 260) and RF, the ceiling temperature can be between 600° C. and 1200° C. The choice of material for the ceiling and susceptor is less restrictive, preferably highly refined graphite.

[0049] GaN For GaN, resistive heating up to 600°C-900°C can be used, preferably using a filament made from pure graphite.

[0050] In either case, higher or lower ceiling temperatures than those stated above may be used, as the optimum temperature will depend on the process chemistry and operating conditions.

[0051] Susceptor Heating Assembly A susceptor heating assembly 350 is provided for heating the wafer carrier.

[0052] The susceptor heating assembly 350 includes a liner 352 that is below the susceptor but above the active components of the susceptor heating assembly 350. The liner 352 may be formed of quartz.

[0053] 5, the susceptor heating assembly 350 has a different structure from the ceiling heater assembly 220. More specifically, the susceptor heating assembly 350 has an outer susceptor heater coil 360 and an inner susceptor heater coil 370 coupled to the outer susceptor heater coil 360. The outer susceptor heater coil 360 is disposed radially outward from the inner susceptor heater coil 370.

[0054] The outer susceptor heater coil 360 includes a water inlet 368 (FIG. 1) for delivering water into the coil 360 and a water outlet 369 (FIG. 1) for withdrawing water from the coil 360. Similarly, the inner susceptor heater coil 370 includes a water inlet 377 for delivering water into the coil 370 and a water outlet 379 (FIG. 1) for withdrawing water from the coil 370.

[0055] Each of the outer susceptor heater coil 360 and the inner susceptor heater coil 370 is similar to the RF ceiling heater coil 260 and is in the form of a water-cooled RF coil. The RF coils may be formed from copper with internal water cooling. The coils 360, 370 are positioned directly below the liner 352.

[0056] Although the susceptor heater assembly in this embodiment is a split-coil design, the combined coils 360, 370 function as a single coil. FIG. 5 shows a split-coil design with feedthroughs and a stabilizing bar 363, similar to the ceiling coil. One feedthrough 365 serves to connect the inner and outer heater coils 360, 370, and another feedthrough 367 connects the split heater coil to an external RF source. The other opening (through-hole) is for the passage of an external device, such as a light pipe. The circle to the right of feedthrough 365 in FIG. 5 is another coil feedthrough similar or identical to feedthrough 365. The circle below feedthrough 367 in FIG. 5 is another coil feed connection similar or identical to feedthrough 367.

[0057] Each of the outer susceptor heater coils 360 and inner susceptor heater coils 370 is supported by a support structure. More specifically, the outer susceptor heater coil 360 is supported by an outer coil support plate 361, which has water cooling, and similarly, the inner susceptor heater coil 370 is supported by an inner coil support plate 371 (FIG. 1). The outer coil support plate 361 is positioned radially outward from the inner coil support plate 371, and each of these components is hollow, allowing water to be received and circulated. There are water inlets for delivering water into the coil support plates 361 and 371 and water outlets for withdrawing water from the coil support plates 361 and 371. Additionally, quartz coil pedestals / supports 380 support the coils 360 and 370 on their respective coil support plates 361 and 371.

[0058] A bottom plate 390 is provided and serves as support for the outer coil support plate 361 and the inner coil support plate 371. The bottom plate 390 includes feedthroughs (ports / openings) for the susceptor heater assembly, the feedthroughs being to the water-cooled coil support plates 361, 371, and the feedthroughs being for the mechanical main and satellite or satellite gas-driven rotations described herein. The bottom plate 390 also includes vacuum connections to the exhaust collectors and shutters containing the gas injectors 102, which introduce up to three, five, or seven different concentric horizontal gas inlet zones. As previously mentioned, the gas injectors 102 can, in one embodiment, be lowered by a robot to a position (lowered position) that provides clear access for removal and loading of a complete wafer carrier into and out of the transfer chamber.

[0059] Additionally, as described further herein, the bottom plate 390 supports a mechanical device, such as a gearbox, configured to rotate both the wafer carrier and the satellites.

[0060] In at least one embodiment, resistive heating may be used on the susceptor to provide temperature tunability.

[0061] Injection of gas into the reaction chamber As described herein, gases are injected into the reaction chamber 201 at at least two different locations and by at least two different means.

[0062] First, the ceiling showerheads 310, 311 allow for the injection of one or more carrier gases and / or one or more etching gases. The showerhead design allows these gases to be injected in a controlled manner into the reaction chamber 201 through the heated ceiling. Second, the central injector 102 functions to inject reactive gases along multiple horizontal concentric zones defined within the central gas injector 102. The reactive gases flow radially outward from the center of the reaction chamber 201 over the satellite substrates.

[0063] Further details regarding the crossflow gas injector 102 illustrated in FIG. 1 are as follows and are shown in an enlarged view in FIG. 4. The crossflow gas injector 102 moves between raised and lowered positions using a conventional drive mechanism, such as a pneumatic drive mechanism. For example, a pneumatic piston 400 can controllably drive the body of the crossflow gas injector 102, which includes multiple concentrically arranged horizontal gas inlets. The body of the crossflow gas injector 102 includes piping that routes reactive (process) gases through the body to the multiple horizontal gas inlets. Additionally, the body of the crossflow gas injector 102 can be water-cooled. Additionally, a vacuum connection can be provided as part of the crossflow gas injector 102.

[0064] In the lowered position of the crossflow gas injector 102, reactive (process) gases are off since none of the gas injector zones are open and positioned above the wafer.

[0065] Parasitic deposition on the ceiling As mentioned above, one of the major drawbacks of conventional planetary reactor systems is parasitic deposition on the ceiling. Parasitic deposition can generate particles, alter the thermal balance within the reactor, and lead to process drift. To avoid this, in-situ chamber etching is frequently used, but this increases the total cycle time of a production run. In-situ cleaning typically shortens the life of components, increasing consumable costs. For certain materials, such as SiC, which are difficult to etch in typical in-situ cleaning gases such as Cl2, HCl, and NF3, in-situ etching is not practical.

[0066] Furthermore, parasitic deposition consumes precursor material that does not remain in the active layer of the substrate, which reduces the overall precursor utilization efficiency and limits the process window for good wafer uniformity (e.g., thickness, composition, and doping).

[0067] The system 200 disclosed herein is configured to avoid or substantially minimize parasitic ceiling deposition, thereby eliminating or reducing the need for in-situ cleaning, improving component life, increasing growth rates, improving gas usage efficiency, and widening the process window for wafer deposition uniformity. Eliminating or reducing in-situ cleaning reduces cycle times and extends preventative maintenance cycles.

[0068] System 200 achieves efficient layer growth on the substrate using a combination of flows introduced by vertical (showerhead designs 310, 311) and horizontal (injector 102) gas inlets, combined with a carrier rotation speed that is 2 to 20 times higher than that of a typical cross-flow planetary reactor. Thus, the present cross-flow reactor (system 200) combines a cross-flow planetary configuration with a faster carrier rotation speed.

[0069] Evaluation of the system 200 confirmed consistency between trials and no ceiling deposition for long (3000 μm) PM intervals.

[0070] exhaust 1 includes peripheral exhaust ports 203 for exhausting gases from exhaust chamber 201. In combination with controlled sidewall temperatures, peripheral exhaust ports 203 are configured to limit parasitic deposition and avoid exhaust clogging. It will be appreciated that any number of different peripheral exhaust ports may be used in system 200.

[0071] gearbox As described above with respect to the drive mechanism of system 100, the wafer carrier and satellites are driven in a manner that allows for independently controlled rotation of each. Specifically, the wafer carrier (wafer carrier body) is configured to rotate at a first speed relative to the base, and the individual satellites mounted inside the substrate carrier can rotate at a second speed relative to the base that is different from the first speed. In one embodiment, the wafer carrier rotates between approximately 50 RPM and 400 RPM, and the satellites rotate between 20 RPM and 40 RPM. In other words, the wafer carrier rotates faster than the satellites.

[0072] The planetary configuration of the mechanical drive can use a single motor to drive both the satellite and the wafer carrier, although reduction gears can be used as described herein. In one embodiment, the wafer carrier and satellite rotate in the same direction. In another embodiment, two motors are used to drive the satellite and wafer carrier, thereby allowing for a variable ratio of speeds between the satellite and wafer carrier.

[0073] 1 schematically illustrates a pair of gearboxes 205 operatively coupled to the pair of satellites to rotate the satellites at a desired speed. The gearboxes 205 are located on the bottom plate 390 of the system 200. These same gearboxes 205 can also function to rotate the wafer carriers.

[0074] It will be appreciated that gearbox 205 may have the same or similar structure as that described herein with respect to system 100, or may have any other suitable structure that performs its intended function.

[0075] Gas-powered rotary drive U.S. Patent Nos. 6,898,395 and 6,983,620, each of which is expressly incorporated herein by reference in its entirety, describe and illustrate a gas drive with single satellite gas control that can be modified and implemented in the system described herein. Gas is supplied into a vacuum-sealed reactor chamber by multiple gas feeds through a hollow shaft ferroelectric. Each gas channel is controlled by an MFC and supplies a single satellite. Gas is supplied to hollow pins to individual gas drives for each satellite.

[0076] Modeling has demonstrated that matching growth rates and uniformity can be achieved on 200mm wafers of various materials. Growth of SiC, GaN, InGaN, GaAs, InAlP, and InGaAsP has been evaluated. Ceiling deposition can be eliminated (SiC) or reduced by over 100 times (for III-N and As / P) compared to conventional cross-flow reactors. Gas utilization efficiency and growth rates are comparable to or higher than cross-flow planetary reactors. Carrier rotation speeds above 100 RPM are appropriate. Speeds up to 400 RPM improve growth rates, improve gas utilization, and widen the process window for uniformity. A gas drive can be used instead of a gearbox drive when the carrier rotation speed is up to 100 RPM.

[0077] Figure 8 illustrates a gas drive mechanism incorporated into a system such as that shown in Figure 26, as well as a modified version of system 200 of Figure 1. Gas is supplied into the vacuum-sealed reactor chamber 201 by multiple gas feeds through a hollow shaft ferroelectric generally designated 410. In Figure 8, there are eight separate satellite gas feeds. For example, there is a first gas feed 411 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a second gas feed 412 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a third gas feed 413 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a fourth gas feed 414 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a fifth gas feed 415 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a sixth gas feed 416 controlled by an MFC (e.g., Ar / H2 or N2 / H2), a seventh gas feed 417 controlled by an MFC (e.g., Ar / H2 or N2 / H2), and an eighth gas feed 418 controlled by an MFC (e.g., Ar / H2 or N2 / H2).

[0078] Each gas channel 411-418 is controlled by an MFC and supplies a single satellite. Gas is supplied to hollow pins 420 to individual gas drives for each satellite. Thus, the system utilizes a gas-powered rotary drive mechanism to control the rotation of each satellite and wafer carrier.

[0079] This type of architecture for system 200 provides superior capabilities compared to conventional systems. System 200 allows operation under isothermal or near-isothermal conditions, where the ceiling temperature is comparable to the carrier temperature. This improves temperature control, reduces temperature sensitivity, reduces wafer bow, and improves repeatability. The addition of flow and adjustable flow mixture through the ceiling, active temperature control of the ceiling, and adjustable carrier rotation speed (e.g., 50 RPM to 400 RPM) provides additional avenues for process tuning. It enables a wider process window, encompassing a wider operating pressure range and better uniformity (thickness, composition, and doping) over a wide range of conditions.

[0080] An actively heated and purged ceiling eliminates or reduces deposition on the ceiling, lowering deflection rates and eliminating chamber drift. Introducing NH3 (carrier gas) through the ceiling increases the decomposition efficiency of NH3, which can extend the growth window to lower temperatures, such as those desirable for growing high-indium-content InGaN films for red emission. Introducing HCl (etchant gas) through the ceiling keeps the ceiling clean for SiC growth, improving GaN growth rates. Additionally, the temperature of the unpurged areas above and around the wafer is controlled so that total accumulation is low enough not to cause memory effects or generate particles.

[0081] One aspect of the present disclosure is to inject a chlorinated gas, such as HCl (in addition to a carrier gas such as H, optionally with Ar, via a heated ceiling (above 1650°C, preferably 1700-1750°C)) to suppress ceiling deposition. In one embodiment, the wafer temperature is about 1650°C, which is a preferred temperature for CVD SiC epitaxy.

[0082] According to the present teachings, good uniformity (thickness and nitrogen doping) can be achieved for SiC at 25 μm / hr and 50 μm / hr. Ceiling deposition is avoided. In typical cross-flow reactors, parasitic ceiling deposition limits the upper limit of growth rates with good uniformity to about 25 μm / hr. Advantageously, the construction of the present system 200 overcomes such deficiencies, thus achieving enhanced growth rates with good uniformity.

[0083] Furthermore, good uniformity (thickness and composition) can be achieved for various III-N and As / P materials, including under isothermal conditions. Ceiling deposition is reduced by over a hundred times compared to wafer growth rates. This reduces in-situ cleaning time and allows less aggressive cleaning chemistries, such as TBCl, to be used to avoid damage to coatings and chamber components. In typical cross-flow reactors, isothermal conditions are not possible due to parasitic deposition on the ceiling. Again, the present system 200 overcomes this deficiency / limitation.

[0084] Based on the foregoing, it will be appreciated that system 200 provides the following advantageous features: an actively heated ceiling with vertical laminar flow (from the showerhead inlet) that is free of parasitic deposition; long PM spacing for optimal run-to-run repeatability and high growth rates; a multi-zone (e.g., five-zone) horizontal flow central injector 102 for optimal within-wafer uniformity; controlled sidewall temperatures and removable traps (exhaust) to limit parasitic deposition and avoid exhaust clogging; and a planetary drive, along with a temperature-controlled ceiling, to provide uniform within-wafer temperatures. These combined features are superior to both conventional vertical rotating disk designs and cross-flow planetary designs.

[0085] Resistive heating of multiple zones in a GaN reactor FIG. 9 is a cross-section of a GaN reactor including a multi-zone resistive heating arrangement. The system of FIG. 9 incorporates a ceiling heater assembly and ceiling showerhead gas injection, as in FIG. 1; however, the susceptor heater is different. More specifically, a multi-zone resistive heater assembly 500 for heating the susceptors (carrier and satellites) is illustrated. The assembly 500 generally includes a water-cooled heater base plate 510. Above the base plate 510 is a radiant heat shield 520, and a multi-zone resistive heater 530 is disposed above the radiant heat shield 520. The heater 530 may include a multi-zone resistive heater of a type (W or Re) appropriate for the intended application.

[0086] As with the other embodiments, the multi-zone resistive heater assembly 500 heats the susceptor to a desired temperature (target temperature or range).

[0087] Automatic loading and unloading of wafer carriers For ease of illustration, in Figures 6 and 10-20, the wafer carrier is designated 600, the satellite housed inside the wafer carrier is designated 610, and the end effector is designated 620. Wafer 611 is supported by satellite 610. As is known, end effector 620 is a device at the end of a robot arm configured to interact with the particular environment in which the robot resides. In this environment, the end effector is a device designed to handle wafers and transport them from one location to another. Wafer carrier 600 has a central opening to accommodate the movement of central gas injector 102.

[0088] 6 shows a monolithic wafer carrier 600, while other embodiments illustrated herein (e.g., FIGS. 19 and 20) show segmented wafer carriers. When the wafer carrier is monolithic, an automated handling device picks up and moves the entire wafer carrier 600.

[0089] GaN or GaAs related materials 10-14 relate to reactor setups for GaN or GaAs related materials. Such reactor setups can include resistive heaters (see FIG. 21).

[0090] 10 shows the reactor in an in-process state, with the reactor gate closed, the shutter closed, and the central horizontal gas injector 102 in a raised position, which allows one or more gas injection zones to open and allows gas to be discharged radially outward from the central gas injector 102 above the wafer.

[0091] 11 shows the reactor in position for loading and unloading of carrier 600. In this position, the reactor gate is open to the vacuum transfer module chamber, the shutter is closed, the central gas injector 102 is moved down to its lowered position, and a robot with end effector 620 is moved into the reactor chamber 201. The end effector 620 moves the carrier 600, including satellites 610 and wafers 611, to an elevated position that allows for unloading of the wafer carrier 600. For initial loading, the end effector 620 moves the carrier 600 into the reaction chamber 201.

[0092] 12 and 13 show the position of the carrier 600 at the wafer loading and unloading station, with two different gripping solutions shown. The carrier 600 with satellites 610 is transported to the wafer loading and unloading station, positioned in its dedicated loading and unloading position, and initialized.

[0093] More specifically, FIG. 12 shows a Bernoulli gripper solution. In this arrangement, a Bernoulli gripper 630 is provided. An end effector 620 equipped with a Bernoulli gripper 630 on a (second) robot from the wafer module picks up the wafer 611 by switching on the gas flow to create a negative pressure to pick up the wafer 611. The processed wafer 611 is then transported to a storage location. This process is repeated for all other processed wafers 611 in the carrier 600. After that task is completed, the carrier 600 is swapped with a cleaned carrier 600 and satellites 610. Fresh, unprocessed wafers 611 are then placed in each satellite 610. The cleaned carrier 600 with the fresh, unprocessed wafers 611 in the satellites 610 is transported into the reactor.

[0094] 13-14 show the lift pin configuration. FIG. 13 shows the lift pin drive 640 with the lift pins 642 in the lowered position. FIG. 14 shows the lift pins 642 in the raised position. In the lift pin configuration of FIGS. 13-14, the wafer 611 is lifted from the satellite 610 by the three lift pins 642 to the raised position for the wafer end effector 620 to grasp the wafer 611. The satellite 610 includes holes that allow the lift pins 642 to pass through. After the wafer end effector 620 engages the processed wafer 611, the processed wafer 611 is transported to a storage location. This process is repeated for all other processed wafers 611 housed in the carrier 600. The used carrier 600 is then exchanged for a cleaned carrier 600 and satellite 610 from the storage facility. The carrier is then positioned and initialized at the dedicated loading and unloading positions for each satellite 610. A fresh, unprocessed wafer 611 is placed into each satellite 610 by raising the lift pins 642 and placing the wafer 611 on the lift pins 642 with the wafer end effector 620. The lift pins 642 are then lowered to place the wafer 611 into a recess in the satellite 610. The cleaned carrier 600 with the fresh, unprocessed wafer 611 is then transported into the reactor.

[0095] SiC related materials 15-18 illustrate processing steps for SiC-related materials using a system 200 that includes an RF susceptor heater and a ceiling heater.

[0096] FIG. 15 illustrates the reactor position during processing (in-process state). In this position, the reactor gate is closed, the shutter is closed, and the central gas injector 102 is in the raised position, allowing gas to flow radially outward from the central gas injector 102. FIG. 16 shows the wafer carrier load / unload position. The satellite includes a satellite ring 615, and the carrier 600 includes a carrier inner ring 601. In this position, the reactor gate is open to the vacuum transfer module chamber. The central gas injector 102 moves to the lowered position, allowing the end effector to move. A robot arm with end effector 620 moves into the reactor chamber 201. The end effector 620 is operated to move the carrier 600 and satellite 610 to the raised position shown in FIG. 16.

[0097] 17 and 18 show the position of the carriers at the wafer loading and unloading station. Carrier 600 and satellite 610 are transported to the wafer loading and unloading station by end effector 620. The carriers are positioned and initialized at their dedicated loading and unloading positions.

[0098] FIG. 17 shows the lift pin drive 640 with the lift pins 642 in the lowered position. FIG. 18 shows the lift pins 642 in the raised position. In the lift pin arrangement of FIGS. 17-18, the wafer 611 is lifted from the satellite 610 by the three lift pins 642 to the raised position for the wafer end effector 620 to grasp the wafer 611. After the wafer end effector 620 engages the processed wafer 611, the processed wafer 611 is transported to a storage location. This process is repeated for all other processed wafers 611 housed in the carrier 600. The used carrier 600 is then exchanged for a cleaned carrier 600 and satellite 610 from the storage facility. The carrier is then positioned and initialized at the dedicated loading and unloading positions for each satellite 610. A fresh, unprocessed wafer 611 is placed into each satellite 610 by raising the lift pins 642 and placing the wafer 611 on the lift pins 642 with the wafer end effector 620. The lift pins 642 are then lowered to place the wafer 611 into a recess in the satellite 610. The cleaned carrier 600 with the fresh, unprocessed wafer 611 is then transported into the reactor. As previously mentioned, the satellites 610 have features (through holes) that allow movement of the pins 642.

[0099] Segmented Carrier 19-20 illustrate a segmented carrier configuration. As shown, in this embodiment, the carrier 700 is formed from multiple separate sections 710 ("pie-shaped sections"), with each section 710 including one satellite 610 / satellite ring 615. In this embodiment, the end effector may be a fork-shaped end effector, and the carrier 700 includes complementary grooves that receive the fork portions (arms) of the end effector. FIG. 20 illustrates the lifting of one separate section 710 from the main body of the carrier 700 by the fork-shaped end effector. The lifted separate section 710 includes one satellite 610 / satellite ring 615.

[0100] The automated loading / unloading process may include the following steps: using a robotic device (end effector) to move one carrier section 710 from the reactor and placing the removed section 710 at a wafer loading and unloading station. Once the carrier section is at the wafer loading and unloading station, the wafer 611 is separated (lifted) from the satellite 610 / satellite ring 615 and further processed and / or transported to a different station. After the wafer is unloaded, the section 710 and satellite 610 / satellite ring 615 are moved to a storage location.

[0101] The cleaned (or new) carrier section 710 (with cleaned satellites 610 / satellite ring 615) is then placed into the reaction chamber. For example, the cleaned carrier section 710 (with cleaned satellites 610 / satellite ring 615) may be brought to a wafer loading and unloading station. A fresh wafer 611 is loaded into section 710 (satellite 610 / satellite ring 615), and then section 710 is loaded into the open space of the segmented carrier inside the reaction chamber. This process is repeated using an indexed controller that rotates the segmented carrier in indexed increments to the unloading / loading position for each carrier section 710. In other words, the carrier rotates in an indexed manner to position one dirty carrier section 710 at the carrier section loading / unloading position. Once the dirty carrier section 710 is in this position, it is removed and processed as described above, and the cleaned carrier section 710 is returned to the carrier. In this manner, continuous removal and replacement of carrier sections 710 occurs.

[0102] Clustered Systems It will be appreciated that the system disclosed herein can be incorporated into a clustered system comprising two reactors.

[0103] Satellite Configuration 21 and 22, in some embodiments, the rotatable platform and satellite ring 116 may be driven by a common motor via separate gears to achieve a rotational speed differential between the rotatable platform and satellite ring 116. This results in a speed differential between the carrier 105 and the satellites 106. This embodiment is preferred when the rotational speed of the carrier significantly exceeds the rotational speed of the satellites, such as when the carrier rotates at 100-1200 rpm and the satellites rotate at 20-40 rpm. In this embodiment, substantial centripetal forces act on the satellites 106A-F. To counter these centripetal forces, the satellites 106A-F may be mounted to the carrier via bushings.

[0104] In one embodiment, the carrier rotates at greater than 50 rpm, preferably greater than 100 rpm, while satellites 106A-F slowly (less than 30 rpm) draw reactants toward the wafer surface and away from the ceiling (to minimize dilution by the ceiling purge).

[0105] The satellite 106 consists of a disk with a hub 191 at its bottom. The hub 191 is positioned within a bushing 193, which is embedded in the base of the carrier 105. The interface between the satellite hub 191 and the bushing 193 is designed to have low friction so that the torque required to rotate the satellite under centripetal force-induced friction is minimized. A low-friction interface can be achieved by coating the mating surfaces with a high-temperature compatible solid lubricant such as MoS2 and WS2. The bushing material and dimensions are selected to minimize thermal imprint of the hub 191 on the wafer. The bushing 193 may be made of a combination of materials, such as fused silica, graphite, SiC, and molybdenum, to achieve the desired characteristics. For example, as shown above, a bushing 193 made from quartz may include two concentric liners 195, 197. The liners 195, 197 may be made from molybdenum, and the interface between the two liners 195, 197 may be coated with a low-friction solid lubricant.

[0106] In this configuration, satellite support 117F includes flexure elements to accommodate slight radial movement of the satellites due to thermal expansion of the carrier. The interfaces between the ends of satellite support 117F and satellites 106A-F are designed to rotationally couple the rotational movement of satellite support 117F and transmit the torque necessary to overcome frictional forces in the bushings.

[0107] Central Crossflow Injector 102 In alternative embodiments, the injector 102 may be centrally positioned within the reaction chamber 201 to affect a substantially horizontal or cross-flow of reactive gas over substrates disposed within the reaction chamber. For example, referring to FIG. 23 , the multi-zone injector 102 may be positioned adjacent the top surface of the wafer carrier 105 so as to have a lateral component with respect to one or more substrate wafers (W) disposed within the wafer carrier 105. Thus, the injector 102 can provide a variable horizontal flow of reactive gas toward the exposed growth surfaces of one or more substrate wafers. As described herein, the multi-zone central injector 102 may be raised and lowered between a load and unload position, in which a wafer carrier can be loaded and unloaded from a load port and a process position, and a raised position, in which reactive gas flows horizontally from the injector 102 and flows radially outward over wafers disposed in satellite positions.

[0108] The injector 102 of Figure 23 and Figure 1 can be thought of as providing a horizontal concentric gas inlet with multiple zones for injecting reactive (process) gases into the reaction chamber 101 by planetary rotation of satellites to compensate for precursor depletion.

[0109] In some embodiments, the centrally located injector 102 can be temperature controlled via a coolant system and can be connected to a gas source for independently introducing one or more of a first reactive gas, a second reactive gas, and / or an inert gas into the reaction chamber 101. Additionally, the injector 102 can include multiple injection zones stacked vertically. For example, in one embodiment, the injector 102 includes multiple inlets 125A-C for injecting a first reactive gas, a second reactive gas, and an inert gas, respectively, into the reaction chamber, as shown in FIG. 23 . In one embodiment, the central injector 102 is a five-zone injector that provides good uniformity (thickness and doping) at a high growth rate (50 μm / hr). In the raised position, all zones (all inlets) are exposed and activated, allowing unimpeded flow of reactive gas from each inlet. Conversely, in the lowered position, none of the zones are activated and all of the inlets are shut off.

[0110] In some embodiments, inlets 125A-C can be separated by horizontal baffles configured to allow separation of process gases into independently adjustable vertical (stacked) zones. In embodiments, the zones can be externally piped, whereby the zones can operate individually or can be grouped together with the appropriate gas mixture supplied to each of the zones. For example, in the case of an injector 102 having seven vertically stacked zones, with zone 1 at the bottom and seven at the top, the zones can be assigned as inert gas (zone 1), hydride (zone 2), alkyl (zone 3), hydride (zone 4), and inert gas (zones 5, 6, and 7). In another embodiment, the zones can be assigned as inert gas (zone 1), hydride (zone 2), alkyl (zone 3), hydride (zone 4), alkyl (zone 5), hydride (zone 6), and inert gas (zone 7). Another possible configuration is inert gas (zone 1), hydride (zone 2), alkyl (zone 3, zone 4), hydride (zone 5, zone 6), and inert gas (zone 7). Other embodiments are also contemplated.

[0111] In one embodiment, a chlorinated gas (optionally containing Ar, in addition to a carrier gas such as H2) is injected through the top zone of the central injector 102 to prevent deposition on the tip of the ceiling inside the reaction chamber.

[0112] The central gas injector 102 has vertically stacked zones with horizontal baffles separating the zones. These baffles may have a triangular shaped cross section to direct gas radially outward toward the wafers surrounding the central gas injector 102.

[0113] In embodiments, the injector 102 may be centrally positioned within the reaction chamber 101. Thus, reactive gases may be introduced into the reaction chamber via the inlets 125A-C to provide a cross-flow component of reactive gas across the exposed growth surfaces of one or more substrate wafers positioned in one or more pockets of the wafer carrier 105. In some embodiments, the injector 102 may be mounted on a bellows assembly, which allows the injector 102 to move vertically up and down relative to the wafer carrier 105 to facilitate removal of the wafer carrier 105 between epitaxial growth cycles. In other embodiments, the injector 102 may be positioned proximate the periphery of the wafer carrier 105, surrounding the carrier 105.

[0114] It will also be appreciated that the central injector 102, which affects a substantially horizontal or cross-flow of reactive gases over a substrate disposed inside the reaction chamber 101, may be used in combination with the showerhead gas inlet arrangement discussed herein, which introduces gases into the reaction chamber from a location in the ceiling.

[0115] 24A-B, in an alternative embodiment, the cover plate 131 can be raised and lowered using a movable, centrally located gas injector 102A. For example, FIG. 24A shows the cover plate 131 in a home position, and FIG. 24B shows the cover plate 131 and injector 102A in an active position. In this embodiment, both the wafer carrier 105 and the individual wafer support disks 106 can be configured to slowly rotate in a cross-flow planetary configuration, with the flow of reactive gases generally directed radially outward from the central injector 102 toward the peripheral exhaust, across the wafer support disks 106.

[0116] Due to the slow rotational speed of the wafer support disks 106, adjacent wafer support disks 106 may rotate in either the same or opposite directions. The central injector 102 is movable on or below the top surface of the wafer carrier 105 during loading and unloading, and can be raised above the top surface of the wafer carrier 105 once the carrier is loaded into the chamber 101. Accordingly, the cover plate 131 may be lifted by the injectors 102 or by a separate lift mechanism 132, as described above. Furthermore, in some embodiments, an additional injector 102B may be positioned above the cover plate 131 to generate a flow of inert gas that flows toward the peripheral exhaust 109.

[0117] 25 , in some embodiments, the system 100 may include a mechanism for cooling or thermal conditioning of the cover plate 131. For example, in one embodiment, the system 100 may include a water-cooled plate 137 disposed on the cover plate 131. In embodiments, the water-cooled plate 137 may be configured to move up and down relative to the cover plate 131 for precise temperature control of the cover plate 131 during operation. Movement of the water-cooled plate 137 may be automated based on data received from in-situ measurements. To ensure monitoring of the wafer temperature during operation, in some embodiments, the cover plate 131 and the water-cooled plate 137 may include temperature monitoring apertures and / or a central viewport. In addition to the water-cooled plate 137, in some embodiments, the system may further include a water-cooled chamber top 102B with a water-cooled viewport 138 and an inlet for purge gas, a linear-acting water-cooled shutter 139 configured to serve as the exterior of the peripheral exhaust 109, and a movable, centrally located water-cooled injector 102A with a configurable reactive gas injector zone.

[0118] 26, wafer satellites 106 may be formed from numerous types of materials, such as graphite, SiC, metal, or ceramic. In some embodiments, it is desirable to form satellites 106 of a material that can readily accommodate additional material 144 in localized areas of the same material or a different material with a different orientation or altered properties in the localized area. For example, as shown in FIG. 26, additional material 144 added to the pocket floor 143 and / or peripheral wall surfaces 145 of wafer pocket 142 can be configured to provide additional support to the wafer (W) and / or compensate for thermal non-uniformities. In one embodiment, additional material 144 can be added to or removed from the pocket floor 143 and / or wall surfaces 145 by a contouring device.

[0119] The additional material 144 can be disposed at several locations along the peripheral wall or bottom surface of the wafer. The additional material 144 can be rectangular, stepped, triangular, or sloped. The material 144 can be added, for example, by evaporation, sputtering, plating, CVD, or by placing additional supports therein. Portions of the satellite 106 can be masked so that the additional material 144 is deposited only in certain areas of the satellite 106. As shown in FIG. 11 , the wafer pocket 142 and additional material 144 can define a variable gap or step height extending from the pocket floor 143 to the bottom surface of the wafer. In some embodiments, the variation in step height can affect the thermal conductivity of the wafer carrier and promote a more uniform temperature profile across the top surface of the wafer. In one embodiment, the satellite 106 can include a heat spreader plate configured to provide a controlled gap between the bottom surface of the wafer and the pocket floor 143 when the wafer is placed within the cavity defined by the heat spreader plate. In an embodiment, the heat spreader plate may be constructed from a material with high thermal conductivity, such as CVD SiC or pyrolytic graphite.

[0120] In one embodiment, portions of the pocket floor 143 are contoured apart to accommodate the height of the various steps extending from the pocket floor 143 to the bottom surface of the wafer. For example, in one embodiment, the wafer support disk 106 is initially manufactured with the pocket floor 143 having a height equal to the highest anticipated point within the final pocket floor 143, such that only material removal is required to achieve the creation of the final pocket floor 143. Material can be removed from the satellites 106, for example, by machining localized areas of the pocket 142. In such an embodiment, it is desirable to form the satellites 106 of material that can be easily machined in localized areas to match a predefined contour. The satellites 106 can be machined using a continuous contour, or localized areas can be machined by pecking with a specialized cutting tool. For example, a small-diameter diamond cutting tool can be used. Cutting tools that operate at high speeds, such as cutting tools using air turbine spindles, can provide the relatively high precision required for processing small pixels.

[0121] Turning now to Figure 27, which illustrates another embodiment. More specifically, a precision multi-wafer metal organic chemical vapor deposition system 1000 is provided and includes a reaction chamber 1001 (sometimes referred to herein as a "process chamber" or "reactor") configured to define a process environment space, and an injector 1010 (alternatively referred to herein as a "gas distribution device") may be disposed within the environment space. It will be understood that system 1000 and reaction chamber 1001 share some similarities with system 200 (Figure 1), and thus like elements are similarly labeled.

[0122] In contrast to the central gas injector 102 of FIG. 1 , the central gas injector 1010 is stationary (it may be fixed to a central ferroelectric feedthrough) and does not move in an up-and-down manner. It will be appreciated that in this embodiment, the wafer carrier comprises a segmented carrier as described herein. The segmented carrier allows for removal of individual segmented carrier components, while the central gas injector 1010 remains fixed and extends vertically through the reaction chamber 1001. More specifically, the carrier of system 1000 comprises a carrier 700 formed from a plurality of separate sections 710 ( FIG. 19 ).

[0123] The individual sections 710 are removed with a device such as a robot end effector configured to remove the carrier ring and wafers. The carrier 700 can be rotated in an indexed manner to allow for individual and sequential removal of the carrier sections 710, such as through a load port. Clearance for removing the carrier can be created by moving the exhaust ring downward or by moving a segment of the exhaust ring.

[0124] The central gas injector 1010 is therefore configured to exert a substantially horizontal or cross-flow of reactive gases over a substrate (wafer) disposed within the reaction chamber 1010. The central gas injector 1010 may have the same attributes as the central gas injector 102 in that it may include multiple injection zones arranged in a concentric, stacked orientation with respect to one another. Gas is supplied to the central gas injector 1010 from below.

[0125] System 1000, like system 200, includes an upper ceiling plate 300 and a plurality of showerhead holes 311 (FIG. 2) that communicate directly into reaction chamber 1001. The showerhead holes 311 can be formed in different patterns to enable uniform distribution of gases into reaction chamber 1001.

[0126] Reaction chamber 1010 comprises a hot-wall reactor and includes heated sidewalls that are water-cooled as a result of the sidewalls having an internal chamber (the same or similar to that described with reference to FIG. 1) through which water circulates. This mechanism allows for control of the sidewall temperature of reaction chamber 1001. As in system 200, the ceiling of reaction chamber 1001 is preferably both heated and includes a showerhead architecture for injecting purge gas into reaction chamber 1001.

[0127] One other difference between system 1000 and system 200 is the different gas drive mechanism. Specifically, instead of having a gas drive mechanism located below the satellites, the gas drive mechanism can be incorporated into a central region of system 1000, and more specifically, the gas drive mechanism may be located along the central axis of reaction chamber 1001. It will thus be appreciated that in this embodiment, the gas drive mechanism is located below and / or as part of central gas injector 1010.

[0128] Generally, gas for the gas drive mechanism is routed through tabs on the outside of the locking mechanism tube and a central gas injector 1010. Thus, gas is supplied into the vacuum-sealed reactor chamber by multiple gas feeds through the hollow shaft ferroelectric. In Figure 26, the multiple gas feeds are generally indicated at 1030. For example, according to one embodiment, there can be eight separate satellite gas feeds. For example, there may be a first gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a second gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a third gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a fourth gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a fifth gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a sixth gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), a seventh gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2), and an eighth gas feed controlled by an MFC (e.g., Ar / H2 or N2 / H2). Each gas channel is controlled by an MFC, and gases are supplied to a single satellite as well by conduits 419 fluidly connected to the ferroelectric feedthrough. Therefore, the system utilizes a gas-powered rotary drive mechanism to control the rotation of each satellite and wafer carrier 700 .

[0129] Thus, system 1000 combines a fixed (stationary) central gas injector 1010 with a segmented wafer carrier 700, along with heated sidewalls and ceiling, as described in reference to system 200.

[0130] One advantage of using a central gas feed for the gas driver is that it simplifies the susceptor (carrier) heater because, unlike some heater designs described herein, the susceptor heater does not need to be split (a split design accommodates gas drivers located directly below the satellites (as opposed to being centrally located)).

[0131] A peripheral exhaust port is illustrated. Various embodiments of systems, devices, and methods have been described herein. These embodiments are provided by way of example only and are not intended to limit the scope of the claimed invention. Furthermore, it should be understood that various features of the described embodiments may be combined in various ways to create numerous additional embodiments. Furthermore, while various materials, dimensions, shapes, configurations, locations, etc. have been described for use in the disclosed embodiments, other than those disclosed may be utilized without departing from the scope of the claimed invention.

[0132] Those skilled in the art will recognize that the subject matter herein may include fewer features than shown in any individual embodiment above. The embodiments described herein are not intended to be a comprehensive representation of how various features of the subject matter herein can be combined. Thus, the embodiments are not mutually exclusive combinations of features. Rather, various embodiments may include combinations of different individual features selected from different individual embodiments, as would be understood by one skilled in the art. Furthermore, elements described with respect to one embodiment can be implemented in other embodiments even if not described in such an embodiment, unless otherwise stated.

[0133] Although a dependent claim may refer to a specific combination with one or more other claims in the claims, other embodiments may also include combinations of the dependent claim with the subject matter of each other dependent claim, or combinations of one or more features with other dependent or independent claims, and such combinations are suggested herein unless it is stated that a particular combination is not intended.

[0134] Any incorporation by reference of the above documents is limited so as not to incorporate subject matter that contradicts the explicit disclosure of this specification. Any incorporation by reference of the above documents is further limited so that any claims contained in the documents are not incorporated herein by reference. Any incorporation by reference of the above documents is even further limited so that any definitions provided in the documents are not incorporated herein by reference, unless expressly included herein. For purposes of interpreting the claims, the provisions of 35 U.S.C. § 112(f) are expressly intended to be disregarded unless the specific terms "means for" or "step" appear in the claims.

Claims

1. 1. A multi-wafer metal organic chemical vapor deposition system, wherein adjacent wafers disposed within the system rotate about their own axes, the system comprising: a reaction chamber having an exhaust system and a ceiling; a multi-wafer carrier including a wafer carrier body and a plurality of wafer carrier disks supported within the wafer carrier body; a ceiling heater assembly disposed along the ceiling above the multi-wafer carrier for heating the ceiling of the reaction chamber; a ceiling injector disposed along the ceiling above the multi-wafer carrier for injecting gas into the reaction chamber; a central gas flow port located at the center of the multi-wafer carrier; a susceptor heater assembly disposed below the multi-wafer carrier.

2. The multi-wafer metal organic chemical vapor deposition system of claim 1 , wherein the multi-wafer carrier body is configured to rotate.

3. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein said central gas flow port comprises a movable central gas flow port including a reactive gas inlet port having at least one injection zone.

4. 4. The multi-wafer metal organic chemical vapor deposition system of claim 3, wherein said reactive gas inlet port has multiple injection zones.

5. 5. The multi-wafer metal organic chemical vapor deposition system of claim 4, wherein the plurality of injection zones are arranged in a concentric, stacked orientation with respect to one another.

6. 6. The multi-wafer metal organic chemical vapor deposition system of claim 5, wherein the plurality of injection zones are oriented parallel to one another to inject at least one gas into the reaction chamber in a cross-flow direction.

7. 2. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the ceiling injector includes an upper ceiling plate and a lower ceiling plate spaced apart from the upper ceiling plate to form an open space therein, the lower ceiling plate having showerhead holes formed therethrough for injecting the gases into the reaction chamber.

8. 8. The multi-wafer metal organic chemical vapor deposition system of claim 7, wherein the ceiling heater assembly is positioned above the ceiling injector and a barrier is positioned therebetween to prevent the gases from the reaction chamber from flowing into the ceiling heater assembly.

9. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the ceiling heater assembly comprises a water-cooled RF coil.

10. 2. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the ceiling heater assembly operates at a first temperature different from a second temperature at which the susceptor heater assembly operates to enable a temperature gradient between the ceiling and the carrier body to be reduced to suppress convection due to a temperature gradient toward the ceiling.

11. The multi-wafer metal organic chemical vapor deposition system of claim 10 , wherein the first temperature is greater than the second temperature.

12. 12. The multi-wafer metal organic chemical vapor deposition system of claim 11, wherein the first temperature is between 600°C and 1200°C and the second temperature is between 600°C and 900°C.

13. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the susceptor heater assembly comprises a split heater coil defined by an outer coil and an inner coil operatively coupled to the outer coil.

14. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the susceptor heater assembly comprises a water-cooled RF coil.

15. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein said wafer carrier body comprises a segmented wafer carrier body, each segment comprising one wafer carrier disk.

16. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the exhaust system comprises a peripheral exhaust located radially outward from each of the multi-wafer carrier, the ceiling heater assembly, and the susceptor heating assembly.

17. 5. The multi-wafer metalorganic chemical vapor deposition system of claim 4, wherein said movable central gas flow port moves between a raised position and a lowered position.

18. 20. The multi-wafer metal organic chemical vapor deposition system of claim 17, wherein in the raised position, all of the plurality of injection zones are in fluid communication with the reaction chamber, and in the lowered position, all of the plurality of injection zones are isolated from the reaction chamber.

19. 18. The multi-wafer metal organic chemical vapor deposition system of claim 17, wherein said lowered position comprises a load / unload position for said multi-wafer carrier and said raised position comprises an in-process position for said multi-wafer carrier.

20. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein the gases injected by the ceiling injector include a carrier gas and / or an etching gas.

21. 21. The multi-wafer metal organic chemical vapor deposition system of claim 20, wherein the carrier gas comprises H2, N2, Ar, or a combination thereof, and the etching gas comprises HCl, Cl2, or TBCl.

22. 10. The multi-wafer metal organic chemical vapor deposition system of claim 1, wherein said central gas flow port is fixed and said wafer carrier body comprises a segmented wafer carrier body, each segment comprising one wafer carrier disk.

23. 23. The multi-wafer metal organic chemical vapor deposition system of claim 22, further comprising a gas drive mechanism including multiple gas feeds located below said central gas flow port and concentric with a central vertical axis of said reaction chamber.

24. 1. A multi-wafer metal organic chemical vapor deposition system, wherein adjacent wafers disposed within the system rotate about their own axes, the system comprising: a reaction chamber having an exhaust system and a ceiling; a multi-wafer carrier including a wafer carrier body and a plurality of wafer carrier disks supported within the wafer carrier body; a showerhead ceiling injector disposed along the ceiling above the multi-wafer carrier for injecting gases into the reaction chamber, the showerhead ceiling injector including an upper ceiling plate and a lower ceiling plate spaced apart from the upper ceiling plate, the lower ceiling plate having showerhead holes formed therethrough for injecting the gases into the reaction chamber; a ceiling heater assembly disposed along the ceiling showerhead ceiling injector for heating the ceiling of the reaction chamber; a central gas injector disposed at the center of the multi-wafer carrier, the central gas injector comprising a reactive gas inlet port having multiple injection zones; a susceptor heater assembly disposed below the multi-wafer carrier; and a multi-wafer metal organic chemical vapor deposition system, wherein the ceiling heater assembly operates at a first temperature different from a second temperature at which the susceptor heater assembly operates to enable a temperature gradient between the ceiling and the wafer carrier body to be reduced to suppress convection due to a temperature gradient toward the ceiling.

25. 25. The multi-wafer metal organic chemical vapor deposition system of claim 24, wherein the first temperature is greater than the second temperature.

26. 26. The multi-wafer metal organic chemical vapor deposition system of claim 25, wherein the first temperature is between 600°C and 1200°C and the second temperature is between 600°C and 900°C.

27. 25. The multi-wafer metalorganic chemical vapor deposition system of claim 24, wherein the central gas injector is movable between an elevated position, in which the plurality of injection zones are in fluid communication with the reaction chamber, and a lowered position, in which the plurality of injection zones are isolated from the reaction chamber.

28. 30. The multi-wafer metal organic chemical vapor deposition system of claim 27, wherein the multiple injection zones are oriented parallel to one another to inject at least one gas into the reaction chamber in a cross-flow direction.

29. 25. The multi-wafer metal organic chemical vapor deposition system of claim 24, wherein the ceiling heater assembly comprises a water-cooled RF coil.

30. 25. The multi-wafer metal-organic chemical vapor deposition system of claim 24, wherein the susceptor heater assembly comprises a split heater coil defined by an outer coil and an inner coil operatively coupled to the outer coil.

31. 25. The multi-wafer metal organic chemical vapor deposition system of claim 24, wherein the susceptor heater assembly comprises a water-cooled RF coil.

32. 25. The multi-wafer metal organic chemical vapor deposition system of claim 24, wherein the gases injected by the showerhead ceiling injector include a carrier gas and / or an etching gas.

33. 33. The multi-wafer metal organic chemical vapor deposition system of claim 32, wherein the carrier gas comprises H2, N2, Ar, or a combination thereof, and the etching gas comprises HCl, Cl2, or TBCl.

34. 33. The multi-wafer metal organic chemical vapor deposition system of claim 32, wherein the gas injected by the showerhead ceiling injector comprises a chlorinated gas through the heated ceiling at a temperature above 1650°C to inhibit deposition on the ceiling.

35. The chlorination gas comprises HCl, and the injection gas is H as the carrier gas, optionally containing Ar. ２ 33. The multi-wafer metal organic chemical vapor deposition system of claim 32, wherein the ceiling is heated to between 1700°C and 1750°C.

36. 25. The multi-wafer metal organic chemical vapor deposition system of claim 24, wherein the plurality of injection zones includes a top injection zone, and wherein chlorinated gas is injected through the top zone of the central injector to prevent deposition on the tip of the ceiling.

37. 1. A multi-wafer metal organic chemical vapor deposition system, wherein adjacent wafers disposed within the system rotate about their own axes, the system comprising: a reaction chamber having an exhaust system and a ceiling; a multi-wafer carrier including a wafer carrier body and a plurality of wafer carrier disks supported within the wafer carrier body, the wafer carrier body comprising a segmented wafer carrier body, each segment including one wafer carrier disk; a ceiling heater assembly disposed along the ceiling above the multi-wafer carrier for heating the ceiling of the reaction chamber; a ceiling injector disposed along the ceiling above the multi-wafer carrier for injecting gas into the reaction chamber; a stationary central gas flow port located at the center of the multi-wafer carrier; a susceptor heater assembly disposed below the multi-wafer carrier; a gas drive mechanism including a plurality of gas feeds located below the central gas flow port, concentric with a central vertical axis of the reaction chamber, and radially inward from the wafer carrier disk.

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