Two-component oxide vapor source, and method and system for using the same

Abstract

To provide a method for forming a two-component oxide vapor precursor for a deposition process.SOLUTION: A method comprises: providing a two-component oxide vapor source; heating the two-component oxide vapor source to form element vapor from an element component included therein; and reacting the element vapor with a solid two component oxide member included therein. The two-component oxide vapor source includes: a closed end and open end; a first area positioned adjacent to the closed end including the element component; and a second area positioned between the first area and the open end and including an enclosed aggregation structure including the solid two component oxide member and a space passing vapor.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 19 / 206,942, filed May 13, 2025, having the subject matter "BINARY-OXIDE VAPOR SOURCE AND METHOD AND SYSTEM FOR USING SAME," and U.S. Patent Application No. 63 / 651,749, filed May 24, 2024, having the subject matter "BINARY-OXIDE VAPOR SOURCE AND METHOD AND SYSTEM FOR USING SAME," all of which are incorporated herein by reference for all purposes. [Background technology]

[0002] Various deposition processes rely on the generation of precursor materials that, when combined at a deposition surface, form a layer of the desired compound. For the deposition of oxide layers, traditionally, a first source provides non-oxide components in vapor form, while another source provides an activated form of oxygen (e.g., oxygen plasma, ozone, atomic oxygen, etc.) that can donate single oxygen atoms to form an oxide layer on the deposition surface. The generation of this activated form of oxygen is energy intensive, which limits the scale at which these oxide deposition processes can operate. Summary of the Invention [Means for solving the problem]

[0003] In some aspects, the technology described herein relates to a method for producing a binary oxide vapor precursor, the method including: encapsulating elemental components in an open-ended vessel including a closed end and a vessel wall extending from the closed end to the open end; introducing solid binary oxide members into the open-ended vessel to form an encapsulated aggregate structure of the solid binary oxide members within the vessel wall, wherein at least a portion of the solid binary oxide members is between the elemental components and the open end of the open-ended vessel; and heating the elemental components to form an elemental vapor that travels toward the open end of the open-ended vessel, wherein as it travels toward the open end, the elemental vapor reacts with the encapsulated aggregate structure of the solid binary oxide members to produce a binary oxide vapor precursor.

[0004] In some aspects, the technology described herein relates to a binary oxide vapor source having a container having a closed end and an open end; a first region located adjacent to the closed end, the first region containing or configured to contain an elemental component; a first heater zone configured to heat the first region to produce an elemental vapor from the elemental component; a second region located between the first region and the open end, the second region containing or configured to contain a solid binary oxide member; and a space adjacent to the solid binary oxide member through which the elemental vapor can pass, wherein the product of the reaction between the elemental vapor and the solid binary oxide member is a binary oxide vapor precursor, and the solid binary oxide member and the space are configured such that the binary oxide vapor precursor formed in the space can exit the binary oxide vapor source through the open end.

[0005] In some aspects, the technology described herein relates to a method for producing a binary oxide vapor precursor for a deposition process, the method including providing a binary oxide vapor source including a closed end and an open end, a first region located adjacent the closed end containing elemental components, and a second region located between the first region and the open end, the second region including an enclosed aggregate structure including a solid binary oxide member and a space through which the vapor can pass; heating the binary oxide vapor source to form an elemental vapor from the elemental components; and reacting the elemental vapor with the solid binary oxide member as the elemental vapor passes through the space in the second region to produce a binary oxide vapor precursor that exits the binary oxide vapor source through the open end.

[0006] In some aspects, the technology described herein provides a material deposition system comprising a binary oxide vapor source and a growth chamber, the binary oxide vapor source comprising a closed end and an open end, a first region located adjacent the closed end that includes or is configured to include an elemental component, a first heater zone configured to heat the first region to produce an elemental vapor from the elemental component, and a second region located between the first region and the open end, the second region including or configured to include a solid binary oxide member, wherein a product of the reaction between the elemental vapor and the solid binary oxide member is a binary oxide vapor precursor, the growth chamber being coupled to the open end of the binary oxide vapor source, wherein the binary oxide vapor precursor exits the open end of the binary oxide vapor source and enters the growth chamber.

[0007] Embodiments of the present disclosure will be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a binary oxide vapor source for producing a binary oxide vapor precursor, according to some embodiments. [Figure 2]1 is a plot of predicted vapor partial pressure versus cell temperature for a selection of binary oxide vapor precursors, according to some embodiments. [Figure 3] 1A-1C illustrate shapes for forming agglomerated structures of substantially spherical granules having a predetermined size distribution, according to some examples. [Figure 4] 10 is a plot of two different probability distributions of granule size or bead size versus bead radius for a given nominal radius, according to some examples. [Figure 5A] 3D plot of an agglomerated structure comprising closely packed columns of granules varying in size according to a Weibble distribution with a b parameter of 3, showing the resulting packing density, according to some examples (see FIG. 4). The grayscale variation indicates the potential for the liquid material at the bottom to wet upwards into the packed bed, thereby forming multiple regions. [Figure 5B] 3D plot of an agglomerated structure comprising closely packed columns of granules varying in size according to a Weibble distribution with a b parameter of 9, showing the resulting packing density, according to some examples (see FIG. 4). The grayscale variation indicates the potential for the liquid material at the bottom to wet upwards into the packed bed, thereby forming multiple regions. [Figure 6A] 1 is a conceptual cross-sectional view of a binary oxide vapor source illustrating the angular emission profile of emitted precursors, according to some embodiments. The cross-section of the vapor source illustrates multiple regions or zones including a vessel further operably coupled to a precursor beam forming region along with a heat source for heating the vessel. [Figure 6B] 1A-1C illustrate various views of exit configurations that may be used to form a predetermined beam flux profile from a binary oxide vapor source of the present disclosure, according to some embodiments. [Figure 6C] 1A-1C illustrate various views of exit configurations that may be used to form a predetermined beam flux profile from a binary oxide vapor source of the present disclosure, according to some embodiments. [Figure 6D]FIG. 10 is a side view of an exemplary emission distribution profile of a binary oxide vapor precursor from an outlet according to some embodiments. [Figure 6E] 1 illustrates a side view of an exemplary emission distribution profile of a binary oxide vapor precursor from an outlet according to some embodiments. [Figure 7] 1 is a plot of calculated Gibbs free energy activity (equilibrium coefficient) versus temperature for various reactive oxygen-containing species, with several examples. [Figure 8A] 1 shows an example schematic of a deposition system including a binary oxide vapor source and an active oxygen-containing species source for depositing an oxide layer on a substrate in a growth chamber, according to some examples. [Figure 8B] 1 shows an example schematic of a deposition system including a binary oxide vapor source and an active oxygen-containing species source for depositing an oxide layer on a substrate in a growth chamber, according to some examples. [Figure 9A] 10 shows plots of modeled partial pressures of GaO, GaO, and O at the exit aperture of a GaO precursor vapor cell versus growth chamber oxygen partial pressure when the cell temperature is 650° C., according to several examples. [Figure 9B] 10 shows plots of modeled partial pressures of GaO, GaO, and O at the exit aperture of a GaO precursor vapor cell versus growth chamber oxygen partial pressure when the cell temperature is 750° C., according to several examples. [Figure 9C] 10 shows plots of modeled partial pressures of GaO, GaO, and O at the exit aperture of a GaO precursor vapor cell versus growth chamber oxygen partial pressure when the cell temperature is 850° C., according to some examples. [Figure 10A] 1 shows a plot of modeled partial pressures of AlO, AlO, and O at the exit aperture of an AlO precursor vapor cell versus oxygen partial pressure in the growth chamber when the cell temperature is 975° C., according to some examples. [Figure 10B]10 shows a plot of modeled partial pressures of AlO, AlO, and O at the exit aperture of an AlO precursor vapor cell versus oxygen partial pressure in the growth chamber when the cell temperature is 1050° C., according to some examples. [Figure 10C] 10 shows a plot of modeled partial pressures of AlO, AlO, and O at the exit aperture of an AlO precursor vapor cell versus oxygen partial pressure in the growth chamber when the cell temperature is 1100° C., according to some examples. [Figure 11A] 1 shows a plot of modeled partial pressures of Ge, GeO, and O2 at the exit aperture of a GeO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 650° C., according to some examples. [Figure 11B] 10 shows a plot of modeled partial pressures of Ge, GeO, and O2 at the exit aperture of a GeO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 700° C., according to some examples. [Figure 11C] 10 shows a plot of modeled partial pressures of Ge, GeO, and O2 at the exit aperture of a GeO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 750° C., according to some examples. [Figure 12A] 1 shows a plot of modeled partial pressures of Si, SiO, and O at the exit aperture of a SiO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 850° C., according to some examples. [Figure 12B] 1 shows a plot of modeled partial pressures of Si, SiO, and O at the exit aperture of a SiO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 900° C., according to some examples. [Figure 12C] 1 shows a plot of modeled partial pressures of Si, SiO, and O at the exit aperture of a SiO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 950° C., according to some examples. [Figure 13A]10 shows a plot of modeled partial pressures of B2O2, B2O, and O2 at the exit aperture of a B2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 900° C., according to some examples. [Figure 13B] 10 shows a plot of modeled partial pressures of B2O2, B2O, and O2 at the exit aperture of a B2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 950° C., according to some examples. [Figure 13C] 1 shows a plot of modeled partial pressures of B2O2, B2O, and O2 at the exit aperture of a B2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 1000° C., according to some examples. [Figure 14A] 10 shows a plot of modeled partial pressures of In2O, In, and O2 at the exit aperture of an In2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 500° C., according to some examples. [Figure 14B] 10 shows a plot of modeled partial pressures of In2O, In, and O2 at the exit aperture of an In2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 550° C., according to some examples. [Figure 14C] 10 shows a plot of modeled partial pressures of In2O, In, and O2 at the exit aperture of an In2O precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperature is 600° C., according to some examples. [Figure 15A] 1 is a phase diagram of Li2O decomposition in an oxygen environment. [Figure 15B] 1 is a phase diagram of Li2O decomposition in an oxygen environment. [Figure 15C] 1 is a phase diagram of Li2O decomposition in an oxygen environment. [Figure 16A] 1 is a modeled plot of expected oxide condensation at the outlet of a binary oxide vapor source operating in an oxygen environment as a function of outlet temperature, according to several examples. [Figure 16B]1 is a modeled plot of expected oxide condensation at the outlet of a binary oxide vapor source operating in an oxygen environment as a function of outlet temperature, according to several examples. [Figure 16C] 1 shows modeled thermodynamic process plots of the driving force (ΔP) for forming In2O (gas) and In2O3 solid reacting with O2, with several examples. [Figure 16D] 1 shows plots of modeled thermodynamic driving forces for three binary oxide precursor species MeO (where Me = (In, Ga, or Al)), with several examples. [Figure 17] 1 is a diagram of a binary oxide vapor source including a multi-zone (two-zone) heating configuration for differentially heating regions of the binary oxide vapor source, according to some examples. [Figure 18A] 1 is a diagram of a binary oxide vapor source including a multi-zone (three-zone) heating configuration for differentially heating regions of the binary oxide vapor source, according to some examples. [Figure 18B] 1 shows a simplified schematic diagram of a cross section of an example binary oxide precursor source, according to some examples. [Figure 18C] 1 shows a simplified schematic diagram of a cross section of an example binary oxide precursor source, according to some examples. [Figure 19] 1 is a diagram of a binary oxide vapor source including a condensation reduction arrangement, according to some examples. [Figure 20] 1 is a system schematic diagram of a deposition system including a binary oxide remote vapor source and an oxygen source, according to some examples. The system further comprises, for example, a gas or precursor distribution system directed with a material flux toward an optionally rotating deposition surface. The deposition surface is thermally coupled to a heater source, which may be internal or external to the vacuum vessel. [Figure 21]1 is a system schematic diagram of another type of deposition system including a binary oxide remote vapor source, according to some examples. The horizontal furnace system further includes, for example, a gas or precursor distribution system that directs a material flux that flows horizontally toward multiple deposition surfaces. The precursor gases are optionally mixed with a carrier gas. The deposition surfaces are thermally coupled to heater sources that may be internal or external to the vacuum or pressure vessel. [Figure 22] 1 is a flow chart of a method for producing a binary oxide vapor precursor for a deposition process. [Figure 23A] 10A-10C illustrate some examples of open-ended vessels including a body and an exit region that can be used to shape a beam flux profile. [Figure 23B] 10A-10C illustrate some examples of open-ended vessels including a body and an exit region that can be used to shape a beam flux profile. [Figure 23C] 10A-10C illustrate some examples of open-ended vessels including a body and an exit region that can be used to shape a beam flux profile. [Figure 23D] 10A-10C illustrate some examples of open-ended vessels including a body and an exit region that can be used to shape a beam flux profile. [Figure 24] Shown is an encapsulated aggregate structure comprising closely packed columns of solid ellipsoidal binary oxide members. [Figure 25] 1 is a plot showing the minimum amount of GaO required to react with the amount of Ga to completely convert Ga and GaO to the GaO (vapor) precursor. [Figure 26A] An example of the process for adding Ga and Ga2O3 granules to a crucible to produce GaO (vapor) is shown. [Figure 26B] An example of the process for adding Ga and Ga2O3 granules to a crucible to produce GaO (vapor) is shown. [Figure 26C] An example of the process for adding Ga and Ga2O3 granules to a crucible to produce GaO (vapor) is shown. [Figure 27]1 is a plot showing the minimum amount of GeO2 required to completely react with a given amount of Ge to form a GeO (vapor) precursor. [Figure 28A] 1 is a cross-sectional view of a binary oxide vapor source according to an exemplary embodiment, showing three material regions enclosed within a vessel, for example; [Figure 28B] FIG. 2 is a cross-sectional view of a binary oxide vapor source according to another exemplary embodiment. [Figure 28C] FIG. 2 is a cross-sectional view of a binary oxide vapor source according to another exemplary embodiment. [Figure 29] 1 is a flowchart of a method for producing a binary oxide vapor precursor according to an exemplary embodiment. [Figure 30] FIG. 2 is a cross-sectional view of a binary oxide vapor source according to another exemplary embodiment. [Figure 31] 26 is a plot similar to FIG. 25 showing two exemplary mass ratios of solid binary oxide component to elemental component evaluated for a binary oxide vapor source according to the present disclosure. [Figure 32] 26A-26C are plots of the total volume of Ga / Ga 2 O 3 mixture as a function of the mass of Ga in a crucible shape according to the example embodiment. [Figure 33] 32 is a plot of the measured GaO flux, φ, versus the binary oxide vapor source temperature for the two exemplary mass ratios mentioned in FIG. [Figure 34] 32 is an Arrhenius plot of the GaO flux φ as a function of the absolute temperature T of the binary oxide vapor source for the two exemplary mass ratios mentioned in FIG. 31. [Figure 35] FIG. 1 shows X-ray diffraction (XRD) 2q-ω scans of a first single-crystalline GaO film epitaxially grown on a 2-inch sapphire wafer with a (0001) orientation and a second single-crystalline GaO film formed using a GaO precursor grown on a 2-inch 4H—SiC substrate with a (0001) orientation in accordance with the present disclosure. [Figure 36] 36 is a UV-visible reflectance measurement thickness map of the b-Ga2O3 film grown on the c-plane sapphire substrate mentioned in FIG. 35. [Figure 37] 36 is a UV-visible reflectometry thickness map of a b-Ga2O3 film grown on a 4H-SiC(0001) substrate mentioned in FIG. 35. [Figure 38] 1 shows a modeled example of the use of two binary oxide vapor sources in combination with an activated oxygen source to form a ternary oxide material, according to several examples. [Figure 39] 1 shows a modeled example of the use of two binary oxide vapor sources in combination with an activated oxygen source to form a ternary oxide material, according to several examples. [Figure 40] 8A, showing a schematic diagram of an example system YY2400 having similar components as described with respect to system YY800 shown in FIG. 8A, further including an additional elemental or molecular source YY2410, according to some examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following description, like reference numerals designate like or corresponding parts throughout the drawings.

[0010] FIELD OF THE DISCLOSURE The present disclosure relates to producing binary oxide precursors.In one aspect, the present disclosure relates to producing binary oxide precursors for deposition processes.

[0011] This disclosure describes systems and methods for producing binary oxide vapor precursors using a binary oxide vapor source. In some cases, a material deposition system includes a binary oxide vapor source and an active oxygen source coupled to a growth chamber, where the binary oxide precursor and the active oxygen can react to form an epitaxial film on a heated substrate in the growth chamber.

[0012] 1, a binary oxide vapor source 100 for producing a binary oxide vapor precursor is shown, according to some embodiments. In this example, the vapor source 100 has a generally bottle-type configuration with an open end 150 and a closed end 160, which in this embodiment includes a neck region 155. The neck region 155 can have a height 157, and the open end 150 can have a width 152 that is generally perpendicular to the height 157. In other examples, the binary oxide vapor source can have a different shape, such as a neckless shape, as described further below.

[0013] The vapor source 100 includes a container 102 having a first region 110 (having a dimension or depth 112) located adjacent to or proximal to a closed end 160 and containing or enclosing an elemental component 115. The vapor source further includes a second region 120 (having a dimension or depth 122) located between the first region 110 and the open end 150, which in this example includes solid binary oxide members 125 configured to form spaces or gaps between the individual members to form a porous layer. For example, the solid binary oxide members 125 may be beads or granules of binary oxide material (e.g., formed by sintering or other production methods). The beads or granules can be formed into a porous layer, for example, by packing the solid binary oxide members 125 into the container 102 and heating it in the presence of the elemental component 115. The porous layer of the solid binary oxide member 125 may allow elemental vapor formed upon heating of the elemental component 115 to enter the second region, traverse the second region, and react with the solid binary oxide member 125 in the second region to form a binary oxide vapor precursor. The formed binary oxide vapor precursor may then exit the open end 150 of the vapor source 100.

[0014] 1 diagrammatically illustrates that upon heating, a single atom 115A of elemental component 115 located in first region 110 enters second region 120 and reacts with binary oxide material comprising solid binary oxide member 125 to form binary oxide precursor gas molecule 130 in second region 120. Due to the porous structure of second region 120, binary oxide precursor gas molecule 130 can traverse this region and then exit through open end 150.

[0015] For example, the binary oxide precursor is A0 (気体) and the solid binary oxide member (e.g., 125 in region 120) may be in the form of A2O 3(固体) The material may include a binary oxide material in the form of:

[0016] More generally, the reaction to form a binary oxide precursor according to the present disclosure can be written as follows: xA (固体または液体) +A m O n(固体) →sA r O (気体) formula 1

[0017] where A is selected from {Ga, Ge, Al, Si, B, Li, or In} and the associated elemental component; m O n(固体) is the corresponding solid binary oxide containing this elemental component.

[0018] The following reactions (Equations 2-8) can be used to produce binary oxides with different cations. The reactions provide examples of elemental components and solid binary oxides that can form vapor or gas binary oxide precursors when reacted together.

[0019] Ga: 4Ga (液体) +GaO 3(固体) →3Ga2O (気体) formula 2 Ga (液体) +GaO 3(固体) →3GaO (気体) formula 2b

[0020] Ge: Ge (固体または液体) +GeO 2(固体) →2GeO (気体) Formula 3

[0021] Al: 4Al (固体) +Al2O 3(固体) →3Al2O (気体) Formula 4 Al (液体) +Al2O 3(固体) →3AlO (気体) Formula 4b

[0022] Si: Si (固体または液体) +SiO 2(固体) →2SiO (気体) Formula 5

[0023] B: 4B (固体) +B2O 3(固体) →3B2O (気体) Formula 6 B (固体) +B2O 3(固体) →3BO (気体) Formula 6b

[0024] In: 4In (固体) +In2O 3(固体) →3In2O<00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​refers to a mixture of species with different Li / O ratios, and "s" is the number of binary oxide precursor gas molecules produced by the equilibrium reaction of Equation 8. Lithium oxide solid components (e.g., granules, powder, pieces, etc.) can react with the surrounding oxygen environment and be tailored to provide substantially Li precursor or LiO precursor. For example, the binary oxide Li produced r The Li / O ratio of the O precursor will depend at least in part on the type or composition of the solid lithium oxide component (e.g., Li2O, or Li2O2).

[0027] The reaction rate of Equation 1 may be modeled according to the following thermodynamic principles:

[0028] The systems and methods for forming binary oxide precursors using binary oxide vapor sources described herein can be operated efficiently by adhering to the following relevant thermodynamic principles.

[0029] The Gibbs free energy of formation of a particular composition is a function of temperature and pressure. The change in Gibbs free energy for a particular reaction pathway can also be calculated with great accuracy. This change in Gibbs free energy for a given reaction can be used to calculate the equilibrium constant for temperatures corresponding to the partial pressures of the separate species involved in the reaction.

[0030] Referring to FIG. 2, a plot 200 of expected vapor partial pressures versus cell temperature for a selection of binary oxide vapor precursors is shown, according to some embodiments. As shown in Equations 1-8, in some cases, different species are present in the same environment. For example, GaO and GaO gases may both be present in a cell reacting elemental Ga with GaO, as described in Equations 2 and 2b. In this example, the expected product partial pressures or fluxes for each of the binary oxide vapor precursors shown have been determined based on a thermodynamic model that includes the reactants versus the temperature and oxygen pressure of the environment. As can be seen from inspection of plot 200, the expected vapor pressures of the binary oxide vapor precursors shown increase with increasing temperature of the binary oxide vapor cell (i.e., "cell temperature").

[0031] In some cases, the aggregate structures and granules can be used in a binary oxide vapor source to form the binary oxide vapor precursors described herein.

[0032] As described above, the binary oxide vapor source includes a first region containing elemental components located at the closed end of the source. It also includes a second region located between the first region and the open end of the source, the second region including solid binary oxide members and spaces between the solid binary oxide members. Elemental vapor (formed upon heating the first region) can pass through this space and react with the solid binary oxide members to form the binary oxide vapor. In one example, the solid binary oxide members and associated spaces are formed as an agglomerated structure enclosed within the vapor source. The agglomerated structure is a closely packed column of solid binary oxide members in granular or bead form.

[0033] In some cases, the aggregate structure is encapsulated to provide a stable structure with density and porosity. Referring to Equation 1, in some instances, the vapor source is provided with as much A as possible. m O n(固体)It may be beneficial to pack the solid binary oxide member (i.e., the solid binary oxide member) while still maintaining sufficient or desired porosity. This may be beneficial, for example, to produce more binary oxide vapor precursor before the source needs to be re-added. In one example, once the aggregate structure is encapsulated, it is formed from solid binary oxide members in particle or granular form having a predetermined size distribution selected to provide a large amount of solid binary oxide members while maintaining porosity. The surface area of ​​the solid binary oxide member is also related to the size distribution and shape of the solid binary oxide members in particle or granular form. Without being limited by theory, this surface area may be advantageous in increasing the reaction rate of the elemental components with the solid oxide member, and high porosity may be advantageous in allowing the produced binary oxide vapor precursor to pass through the region containing the porous solid oxide member and exit the source.

[0034] Referring now to FIG. 3, a diagram 300 is shown illustrating a shape for forming an agglomerated structure comprising granules having a predetermined size distribution, according to some embodiments.

[0035] In this example, three granules 310, 320, 330 are shown having a generally spherical configuration, with each granule 310, 320, 330 having a different radius, α1, α2, and α3, respectively, and contacting each other at points P1 (between granules 310 and 330), P2 (between granules 310 and 330), and P3 (between granules 320 and 330), forming voids 350 between the granules 310, 320, 330. As will be appreciated, the size of the voids or spaces 350 depends on the size distribution of the granule radii, α1, α2, and α3. As an example, the size of the voids 350 decreases as the size of the granule 320 decreases (the sizes of the granules 310 and 330 are held constant). In general, it is expected that as the variation in granule size increases, the granules will be more densely packed and therefore the voids between the encapsulated agglomerated structures formed from these granules will be smaller.

[0036] Referring now to FIG. 4, a plot 400 of two different probability distributions (probability densities) of granule or bead sizes versus bead radius (particle radius), each having a given nominal radius, is shown, according to some embodiments.

[0037] In this example, the bead radius size is calculated using a Weibble distribution (

number

[0038] As illustrated in this example, a population of granules with a high Weibull b number has a narrower distribution of granule sizes compared to a population of granules with a low Weibull b number. Plot 400 compares distributions 420, 440 where the Weibull b number is 3 and 9, respectively.

[0039] 5A, a 3D plot 500 of an agglomerated structure including closely packed columns of granules 520 that vary in size according to a Weibull distribution with a b parameter of 3, illustrating the resulting packing density, according to some embodiments (see FIG. 4). In some cases, the columns of granules 520 include a first wet region 512, a second semi-wet region 514, and a third dry region 516. In some cases, the columns of granules 520 include the first wet region 512, the second semi-wet region 514, and a third semi-wet region 516. In such cases, the second semi-wet region 514 can contain more liquid than the third semi-wet region 516.

[0040] 5B, which is a 3D plot 550 of an agglomerated structure including closely packed columns of granules 570 that vary in size according to a Weibble distribution with a b parameter of 9, illustrating the resulting packing density, according to some embodiments (see FIG. 4). In some cases, the columns of granules 570 include a first wet region 562, a second semi-wet region 564, and a third dry or semi-wet region 566. In some cases, the second semi-wet region 514 can contain more liquid than the third dry or semi-wet region 516.

[0041] In these examples, the closely packed column of granules 520, corresponding to a low Weibble b number of 3, is more closely packed than the column of granules 570, corresponding to a high Weibble b number of 9. The average pore size is smaller in the closely packed column of granules 520, corresponding to a low Weibble b number of 3, compared to the column of granules 570, corresponding to a high Weibble b number of 9. Thus, there is a greater amount (volume and mass) of solid binary oxide material in the closely packed column of granules 520, corresponding to a low Weibble b number of 3, compared to the column of granules 570, corresponding to a high Weibble b number of 9.

[0042] Therefore, by using solid binary oxide elements with a specified (or tailored) particle size distribution, the interaction characteristics of the binary oxide elements with elemental vapor can be modified. This is done by modifying the surface area available for interaction with the elemental vapor and the effective porosity of the column of granules, which affect the flow rate of elemental vapor through the column of granules. The total amount (volume and mass) of solid binary oxide elements within the enclosed volume of the source can also be modified by the size distribution.

[0043] The size distribution of the solid binary oxide elements in the sources described herein may be a Weibull distribution, as shown in FIG. 4, or may be other types of distributions, such as a Gaussian distribution, a normal distribution, a multimodal distribution, or other types of irregular distributions. The average size and size range of the particles may also differ from those shown in the example distribution of FIG. 4. For example, a distribution of solid binary oxide elements (e.g., approximately spherical) may have an average size (or diameter) of about 1 mm, a minimum size (or 1st, 5th, or 10th percentile) of about 0.5 mm, and a maximum size (9th, 95th, or 99th percentile) of 2 mm to 3 mm. In other cases, the solid binary oxide elements may have an average size less than 0.5 mm or greater than 3 mm. In some cases, the solid binary oxide elements are greater than about 1 micrometer, greater than about 5 micrometers, or greater than about 10 micrometers. In some cases, if the solid binary oxide members are too small, they may solidify (e.g., over time as the source operates) to form blocks of solid binary oxide components that do not have enough pores or spaces or have relatively few pores or spaces through which the elemental vapor can flow. In such cases, the source may become clogged and cease to operate.

[0044] In one example, there is a desired total mass of solid binary oxide elements available to react with the binary oxide vapor source, and a desired flow rate or pressure at the open end that depends on the porosity of the packed column. In some applications, this combination of both material quantity and porosity requirements can be achieved by selecting an appropriate size distribution of the granules. While the above discussion is in the context of approximately spherical granules, it should be understood that similar principles apply to solid binary oxide elements of other shapes; i.e., the size distribution can be selected to obtain the desired properties of a closely packed column of these elements, such as using a bimodal or multimodal distribution. For example, the solid binary oxide elements may be oblate spheroidal, spheroidal, rod-shaped, disc-shaped, platelet-shaped, or irregularly shaped, or may have a mixture of different shapes. For non-spherical solid binary oxide elements, the size distribution can describe the longest dimension of each solid binary oxide element, or a representative dimension or aspect ratio between the dimensions of the solid binary oxide elements.

[0045] 5A and 5B, in one example, the density of the granules may be greater than the density of the liquid form of the elemental component (e.g., Ga), and the tightly packed column or encapsulated aggregate structure 520, 570 of solid binary oxide material may be divided into three regions moving from the closed end toward the open end of the vapor source: a first wet region 512, 562 where the granules are partially immersed in the liquid elemental component; a second semi-wet region 514, 564 where the granules are partially immersed in the liquid elemental component and / or where, upon heating, elemental vapor from the liquid elemental component reacts with the granules; and a third dry region 516, 566 of the granules, which can act as a filter by reacting with any remaining elemental vapor that may pass through the semi-wet region 514, 564 without reacting. Thus, in some cases, the "dry" region 516, 566 may contain some liquid elemental component.

[0046] 5A and 5B, the degree of "wetting" is shown on a gray scale, with darker areas indicating more liquid elemental constituents or elemental vapors. As can be seen by comparing FIGS. 5A and 5B, the semi-wetted region 512 in FIG. 5A extends further up the granule column than the equivalent semi-wetted region 562 in FIG. 5B. This reflects the more efficient packing density of the granule column 520.

[0047] Referring now to FIG. 6A, there is shown a fragmentary cross-sectional view of a binary oxide vapor source 600 illustrating a modeled emission distribution profile 650, according to some embodiments.

[0048] Binary oxide vapor source 600 comprises a vessel 602 having a closed end 605 and an open end 608. In one example, the open end comprises an outlet 610 configured to allow a binary oxide vapor precursor to be emitted or exit the binary oxide vapor source 600 with a modeled emission distribution profile 650 (e.g., profiles 655 and 657) (or the binary oxide precursor has a particular flux or emits a desired partial pressure). Binary oxide vapor source 600 further comprises a heating arrangement including a heating zone 620 controllable to heat vapor source 600 to a predetermined temperature along its length.

[0049] In some embodiments, the outlet 610 has an effective outlet opening diameter D (i.e., D outlet ) and the characteristic exit length L in the emission direction (i.e., L outlet The emission distribution profile characteristic of the outlet 610 may be primarily L outlet and depends on the exit conductance Q outlet is mainly D outlet Generally, L outlet decreases with increasing .

[0050] In some embodiments, outlet 610 may be configured as multiple small apertures (each with an associated aperture size) or a single aperture. Figure 6B shows a top-down schematic view of an example of a source outlet 685 having an aperture 686. Figure 6C shows a top-down schematic view of an example of a source outlet 687 having a single aperture 688. In some cases, the outlets may each have a diameter D n and then configured with a plurality of openings 686 having an effective exit opening diameter D outlet is the individual diameter D n The calculated diameter can be calculated from the diameter of the opening 686 and the diameter of the opening 688. Instead of using one large opening of comparable size, multiple openings are used, combining them in a manner that accounts for losses. This can be contrasted with the outlet 687 having a single opening 688. In some cases, openings 686 and 688 have larger diameters than conventional openings for epitaxial deposition systems (e.g., MBE). Larger openings can be advantageous to prevent blockage due to the deposition of solid binary oxides, which can block the openings. For example, openings 686 and / or 688 can be between about 0.1 mm and about 10 cm, or between about 1 mm and about 10 cm, or between about 10 mm and about 10 cm, or between about 0.1 mm and about 10 mm, or between about 1 mm and about 10 mm, or between about 10 mm and about 10 mm, or greater than 10 mm, or greater than 10 cm. For example, opening 686 can be between 1 mm and 10 mm. In another example, opening 688 can be greater than about 10 cm. In some cases, it may be advantageous to heat outlets 685 and 687 to prevent or reduce the deposition rate of the solid binary oxide from clogging the openings.

[0051] In some embodiments, the aspect ratio of the opening, generally defined as L / D, is set to produce a desired beam or emission distribution profile, operating pressure (or flux), and outlet operating pressure differential at the opening (i.e., the difference between the interior space of the vapor source and the exterior space at the open end of the vapor source) according to the requirements of the deposition process to which the binary oxide vapor precursor is delivered.

[0052] In some embodiments, the outlet is configured to provide a cosine nθ flux distribution to any receiving chamber to which the binary oxide vapor precursor is being delivered. For example, the outlet aspect ratio L / D may be selected to provide an angular emission distribution profile at some deposition surface at a distance "d" from the outlet. This distribution is generally in the form of a cosine flux distribution, where n increases with the outlet aspect ratio, and can form a more directed beam (e.g., compare emission distribution profile 657 with profile 655 in FIG. 6A).

[0053] 6D and 6E, which illustratively show angular emission distribution profiles 680 and 690 (shown in side view) of binary oxide vapor precursor from outlets 685 and 687, respectively. As can be seen, the effect of the high aspect ratio of the individual openings 686 in outlet 685 results in a more directed angular emission distribution profile 680 (i.e., a larger n in the cosine nθ flux distribution) of the binary oxide vapor precursor emitted from the combination of openings 686 when compared to angular emission distribution profile 690 of the binary oxide vapor precursor emitted from a single opening 688 in outlet 687.

[0054] Figure 6A also shows suggestive locations of a first wet region 612 where the solid binary oxide elements are immersed in the liquid elemental component, a second semi-wet region 614 where the solid binary oxide elements are partially immersed in the liquid elemental component and / or elemental vapor from the liquid elemental component reacts with the solid binary oxide elements, and a third dry region of the solid binary oxide elements 616. For example, the solid binary oxide elements in the source of Figure 6A may be similar to those shown in Figures 5A and 5B as closely packed columns of solid binary oxide elements (granules).

[0055] In some cases, the solid binary oxide member may be less dense than the elemental components in the binary oxide vapor sources described herein. In such cases, the solid binary oxide member may be completely or partially suspended on top of the elemental components, and region 612 (or a lower portion of region 612) may contain only the elemental components. In other cases, the solid binary oxide member may be denser than the elemental components, and region 612 (including the lower portion of region 612) may contain a mixture of the elemental components and the solid binary oxide member.

[0056] The binary oxide vapor source 600 in this example utilizes a heater zone 620 extending along the length of the vapor source 600 to heat (e.g., uniformly heat) regions 612, 614, and 616 of the vapor source 600. The heater zone 620 can include a resistive heater, a radiative heater, or any type of heater capable of providing heat to the source 600. For example, in some cases, the crucible is at least partially within a vacuum chamber, such that there is a vacuum gap between at least a portion of the heater zone 620 and the vessel 602. In such cases, at least a portion of the heater zone 620 is a radiative heater that radiatively transfers heat to the vessel 602 through the vacuum gap. In some cases, the heater of the source 600 can be controlled using, for example, a processor coupled to a temperature measurement sensor (e.g., a thermocouple) configured to measure the temperature outside or inside (or adjacent to) the source.

[0057] The binary oxide vapor precursors and sources described herein can be used to form oxide layers in a deposition environment. The method of growing oxide films using the binary oxide vapor precursors and sources described herein can be carried out according to the following thermodynamics.

[0058] Referring now to FIG. 7, a plot 700 of calculated Gibbs free energy activity (equilibrium coefficient) data versus temperature for various reactive oxygen-containing species according to some embodiments from the National Institute of Standards and Technology Joint Army Navy Air Force (NIST JANAF) is shown.

[0059] A higher Gibbs free energy indicates a more reactive oxygen-containing species. The species, in the order shown in plot 700 from most reactive to least reactive, are atomic oxygen, O * 710, O atom anion 720, ozone O 3 730, nitrous oxide N 2 O 740, molecular nitrogen N 2 750 (shown for comparison purposes), and molecular oxygen O 2 760. The curve for the O atom cation falls outside the range of Gibbs free energies plotted on the y-axis of plot 700.

[0060] As can be seen from the plot in Figure 7, atomic oxygen O * (see 710) is a particularly reactive, activated oxygen-containing species suitable for reacting with binary oxide precursors to form oxide layers in deposition or growth systems. In various embodiments, a radio frequency (RF) source is used to form a plasma and "split" molecular oxygen, O, to form O. * RF plasma sources are particularly convenient for producing atomic oxygen on demand, but in some cases this process is relatively inefficient, resulting in a partial pressure of about 1% O in the beam produced by the plasma source. * A mixture of oxygen species is produced, including 99% partial pressure O2.

[0061] As can be seen from Figure 7, another potential active oxygen-containing species suitable for forming oxide layers is ozone O3 (see 730), but atomic oxygen O *Similarly, the use of O3 is generally associated with relatively high oxygen partial pressures O2, given that O3 rapidly decomposes to O2. O3 can be a good source of active oxygen-containing species for oxide deposition processes, but it is highly reactive and may therefore require enhanced safety handling procedures; as a result, RF plasma sources are generally preferred for most conventional oxide deposition applications.

[0062] 8A, a system schematic diagram of a deposition system 800 including a binary oxide vapor source 850 and an active oxygen-containing species source 860 for depositing an oxide layer on a substrate 820 is shown, according to some embodiments. The deposition system 800 further includes a vacuum growth chamber 810, generally configured so that a binary oxide precursor reacts with the active oxygen-containing species to form an oxide layer on the substrate 820. The substrate 820 can be a single crystal substrate, and the oxide layer can be epitaxially deposited on the single crystal substrate. The substrate 820 can also be a composite substrate having a base layer (e.g., a polycrystalline layer) and a single crystal layer on its surface, and the oxide layer can be epitaxially deposited on the surface of the single crystal layer of the composite substrate. In some cases, a polycrystalline oxide layer can be deposited on the substrate 820, and the substrate 820 can have crystalline, single crystal, polycrystalline, or amorphous material on its surface.

[0063] System 800 also includes a sensor 855 that measures the type(s) and / or flux(es) of species within chamber 810. In some cases, sensor 855 is a residual gas analyzer (RGA), which can measure the type and amount of species in the environment using a mass spectrometer. In some cases, sensor 855 is a beam flux monitor (BFM), which can measure the flux of species within the chamber by ionizing the species in an electric field and measuring the resulting current. Sensor 855 can be other types of sensors that indicate the type(s) and / or flux(es) of species within chamber 810, such as a quartz crystal microbalance (QCM) or other types of pressure gauges. In some cases, there can be multiple sensors 855. For example, system 800 can include an RGA and a BFM.

[0064] Additionally, the system 800 may also include other sensors (not shown), such as a pressure sensor to measure the pressure within the chamber 810 and a temperature sensor(s) to measure the substrate temperature.

[0065] In some cases, a binary oxide source described herein (e.g., binary oxide source 850) may be coupled to one or more sensors (e.g., sensor 855), and the binary oxide source can be controlled using closed-loop feedback based on information from the sensor(s). The binary oxide source can be coupled to a processor used to control the source. The processor can also be coupled to one or more sensors and used to control the binary oxide source using information from the sensor(s). For example, the sensor can be an RGA or BFM, and the processor can control the temperature setpoint of the binary oxide source to maintain or target the binary oxide precursor flux measured by the sensor. In this example, the processor controls the temperature setpoint using information from the RGA and / or BFM sensor(s), and the processor can also control one or more heaters of the binary oxide source using information from the thermocouples. This can be advantageous because the flux of precursor species can vary over time, and the active closed-loop feedback described above can improve flux stability, thereby providing improved control over the composition, thickness, and / or material quality of the film being grown.

[0066] In addition to atomic oxygen, other oxidant sources, such as carbon monoxide (CO), nitrous oxide (NO), and nitric oxide (NO) sources, can be used in addition to or in place of the active oxygen-containing species source 860 of the system 800. These other oxidants can be used to deposit oxide layers on the substrate 820, providing opportunities for functional doping. However, these other oxidants add additional complexity to thermodynamic modeling. For example, CO and NO can oxidize MO(g) to MO(s), incorporating C or N atoms into the film. In another example, NO acts simultaneously as a strong oxidant and nitrogen source.

[0067] For example, for Group III metals (“M”) such as Ga, In, or Al, the following general reaction scheme applies when using these other oxidizing agents: M2O(g)+2N2O(g)→M2O3(s)+2N2(g) Equation 9a M2O(g)+2NO(g)→M2O3(s)+N2(g) Equation 9b M2O(g)+2CO(g)→M2O3(s)+2C(s) Equation 9c M2O(g)+CO2(g)→M2O3(s)+C(s) Equation 9d

[0068] Incorporating nitrogen and carbon during oxide layer growth is an effective strategy to introduce deep acceptors into oxide materials. These acceptors can compensate for oxygen vacancies (which would otherwise contribute to n-type conductivity), potentially enabling the realization of semi-insulating or even p-type films.

[0069] This methodology provides a thermodynamic framework for modeling the equilibrium growth of ternary oxide systems using suboxide sources in an MBE environment. It is extendable to tertiary and quaternary systems and can be calibrated using fitted equilibrium constant (K(T)) values ​​(e.g., derived from NIST JANAF or NASA thermochemical data). The use of alternative oxidants, such as CO, NO, and NO, opens additional routes for doping control and enables the synthesis of semi-insulating or compensated oxide materials.

[0070] Referring now to FIG. 8B, a system schematic diagram of a deposition system 802 including a binary oxide vapor source 852 and an active oxygen-containing species source 862 for depositing an oxide layer on a substrate 822 is shown, according to some embodiments. In this example, the substrate 822 is heated using a radiant heater 814. The substrate 822 may optionally be rotated to improve uniformity. The binary oxide vapor source 852 and the active oxygen-containing species source 862 are shown oriented in this example so that they point off-center from the substrate 822. The incident directions of the light sources 852 and 862 (shown as dashed arrows in FIG. 8B) intersect the surface of the substrate 822 at a location significantly away from the center of the substrate 822. The center of the substrate 822 is the intersection of the substrate 822 and the normal arrow 865, as shown in FIG. 8B. Such an arrangement may be beneficial in some cases, such as in combination with rotation of the substrate 822. The deposition system 802 further includes a vacuum growth chamber 812, generally configured to react a binary oxide precursor with an active oxygen-containing species to form an oxide layer on the substrate 822. In this vacuum chamber configuration (e.g., in an MBE system), an open end of a binary oxide vapor source 852 is within or at the boundary of the growth chamber 812. Region 854 is also shown in FIG. 8B, which is a region where species within the chamber (e.g., active oxygen) can react with material at, on, or within the binary oxide vapor source 852. For example, a solid binary oxide material may be deposited, in some cases, at the open end or edge of the binary oxide vapor source 852. A pump 872 is coupled to the growth chamber 812 and is used to create a vacuum.

[0071] In some cases, system 802 includes a vertically oriented binary oxide source 856. System 802 may include one binary oxide source 852 or 856. In other cases, system 802 may include two oxide sources 852 and 856, for example, to form a ternary oxide material from two different binary oxide precursors (e.g., AlO and GaO to form (Al × Ga 1-x) 2O3). In some cases, system 802 includes a binary oxide source 856 that is vertically oriented and has an incident direction (indicated by the dotted line) that is significantly offset from the center of substrate 822.

[0072] It will be appreciated that the deposition systems 800 and 802 of Figures 8A and 8B relate to the configuration of molecular beam epitaxy (MBE) systems and may be any type of epitaxial layer-based deposition system, such as, but not limited to, a chemical vapor deposition (CVD)-based system (e.g., a molecular-organic, chemical vapor deposition (MOCVD)-based system), an atomic layer deposition (ALD)-based system, or other system.

[0073] As previously mentioned, commonly used reactive oxygen-containing species, such as ozone O and atomic oxygen O, * For many cases, O * and / or associated with a relatively high partial pressure of O relative to O, which is also in close proximity to or near the open end or outlet of the binary oxide vapor source. This proximity can result in reaction between the binary oxide vapor and molecular oxygen, forming oxide "condensate" 890 (shown in FIG. 8A) at the outlet opening of source 860 instead of substrate 820. This buildup of condensate primarily serves to reduce the flow of the binary oxide vapor source and, in some embodiments, can even substantially block the outlet opening.

[0074] The expected condensate buildup from the reaction of a binary oxide vapor source with molecular oxygen can be modeled for cell temperature and growth chamber oxygen partial pressure based on thermodynamic considerations and parameters such as temperature, Gibbs free energy (G), equilibrium constant (K), and oxygen pressure.

[0075] 9A-9C, plots of modeled partial pressures of GaO, GaO, and O at the exit aperture of a GaO precursor vapor cell versus growth chamber oxygen partial pressure (e.g., from separate oxygen) are shown for cell temperatures of 650°C (shown in plot 910), 750°C (shown in plot 930), and 850°C (shown in plot 950) in accordance with some embodiments.

[0076] Considering the plot of 910 for a cell temperature of 650°C, 1 x 10 -6 Torr to 2×10 -6 Examination of the growth chamber oxygen partial pressure at Torr reveals a dramatic drop in the GaO precursor partial pressure, followed by a sudden increase in the growth chamber oxygen partial pressure 920, which then tracks the growth chamber oxygen partial pressure. This indicates that despite molecular oxygen's relatively low reactivity compared to atomic oxygen (as an example), its presence in the growth chamber under sufficient pressure can overwhelm the production of the GaO precursor, resulting in the formation of GaO condensate at the source exit aperture. In summary, the presence of molecular oxygen can negate the production of the binary oxide precursor, resulting in the formation of oxide condensate before any oxide is deposited on the substrate.

[0077] Considering plots 930 and 950, which correspond to plot 910 but at higher cell temperatures of 750°C and 850°C, respectively, it can be seen that the effect of higher cell temperature is to increase the tipping point in the oxygen partial pressure in the growth chamber, above which a runaway reaction occurs between oxygen and the GaO precursor, forming GaO condensate.

[0078] As can be seen and confirmed from FIG. 7, atomic oxygen O * Considering that atomic oxygen O is more reactive than molecular oxygen, * This effect becomes even more pronounced when is present at the exit opening of the source.

[0079] 9A-9C and 10A-15C show examples of modeled partial pressures of species at the exit aperture of a precursor vapor cell used to produce different types of binary vapor precursors (e.g., GaO, AlO, GeO, SiO, BO, InO, and LiO). The species may be produced in the binary oxide vapor sources described herein, for example, according to the reactions shown in Equations 1-8. The y-axis in FIGS. 9A-15C is the partial pressure of oxygen (in Torr) input into the system or chamber. In FIGS. 9A-15C, the oxygen curves in the plots correspond to the expected oxygen partial pressure in the chamber near the source, taking into account possible reactions between oxygen and species generated by the source.

[0080] In some of the examples shown in Figures 9A-15C, the pressure in the chamber is sufficiently low (e.g., below 1e-4 Torr) that the mean free path of the species generated by the binary oxide vapor source is longer than the distance from the source to the substrate (e.g., in a vacuum system or MBE system configuration). In other examples described herein, the pressure in the chamber is higher (e.g., above 1e-4 Torr), and the mean free path is shorter than the distance from the source to the substrate (e.g., in a flow-through furnace or MOCVD system configuration). In systems using such high pressures, for example, gas-phase reactions between the binary oxide vapor precursor and the activated oxygen source are more likely to occur, forming solid binary oxide particles (or powder) in the growth chamber. In such short mean free path configurations where gas-phase reactions can occur (e.g., in a flow-through furnace or MOCVD system), the substrate temperature can be elevated to form high-quality films. Alternatively or additionally, in systems using such higher pressures, the introduction of reactants (e.g., one or more binary oxide precursors and active oxygen) can be spatially controlled to reduce or minimize areas within the chamber where gas-phase reactions can occur. This can be useful to prevent deposition of solid oxide material on surfaces within the chamber or system other than the substrate. For example, the opening of the active oxygen source can be positioned away from the opening of the binary oxide source within the chamber, and / or the active oxygen source can be oriented so that the beam of active oxygen species is directed to intersect the substrate on the opposite side from the irradiated beam of binary oxide precursor from the binary oxide source, as shown in FIG. 8B.

[0081] 10A-10C, plots are shown modeling the partial pressures of AlO, AlO, and O at the exit aperture of an AlO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperatures are 975° C. (shown in plot 1010), 1050° C. (shown in plot 1030), and 1100° C. (shown in plot 1050), respectively, according to some embodiments. The AlO precursor can be, for example, AlO or (Al x Ga 1-x)2O3 films.

[0082] 11A-11C, plots are shown modeling the partial pressures of Ge, GeO, and O at the exit aperture of a GeO precursor vapor cell versus the oxygen partial pressure in the growth chamber when the cell temperatures are 650° C. (shown in plot 1110), 700° C. (shown in plot 1130), and 750° C. (shown in plot 1150), respectively, according to some embodiments. The GeO precursor can be, for example, GeO or (Si x Ge 1-x ) can be used to grow O2 films.

[0083] 12A-12C, plots of modeled partial pressures of Si, SiO, and O at the exit aperture of an SiO precursor vapor cell versus growth chamber oxygen partial pressure are shown for cell temperatures of 850° C. (shown in plot 1210), 900° C. (shown in plot 1230), and 950° C. (shown in plot 1250) according to some embodiments. The SiO precursor may be, for example, SiO or (Si x Ge 1-x ) can be used to grow O2 films.

[0084] 13A-13C, plots of modeled partial pressures of BO, BO, and O at the exit aperture of a BO precursor vapor cell versus growth chamber oxygen partial pressure are shown for cell temperatures of 900° C. (shown in plot 1310), 950° C. (shown in plot 1330), and 1000° C. (shown in plot 1350) according to some embodiments. The BO precursor can be, for example, BO or (B x Ga 1-x )2O3 films.

[0085] 14A-14C, plots of modeled partial pressures of InO, In, and O at the exit aperture of an InO precursor vapor cell versus growth chamber oxygen partial pressure are shown for cell temperatures of 500° C. (plot 1410), 550° C. (plot 1430), and 600° C. (plot 1450) according to some embodiments. The InO precursor can be, for example, InO or (In x Ga 1-x )2O3 films.

[0086] 15A and 15B show the relationship between the cell temperature and sLi r 15A and 15B show plots of modeled partial pressures of Li, LiO, LiO, and LiO at the exit aperture of an O precursor vapor cell. Plot 1510 in FIG. 15A models a growth chamber oxygen partial pressure (PO) of 1e-10 atm, and plot 1530 in FIG. 15B models a growth chamber oxygen partial pressure of 1e-4 atm.

[0087] Figure 15C shows the oxygen partial pressure (φ(O)) in the growth chamber at a temperature of 1200 °C. 0 ) for sLi r 15 shows plot Y1550, in which the partial pressures of Li (1554), LiO (1558), LiO (1552), and LiO (1556) at the exit aperture of the O precursor vapor cell are modeled. At oxygen partial pressures below about 2e-6 Torr, the source produces more elemental Li than LiO, and at oxygen partial pressures above about 2e-6 Torr, the source produces more LiO than elemental Li. As described further herein, high oxygen partial pressures can cause problems with condensation of solid lithium oxide species; however, in the case of lithium, it can be advantageous to operate at oxygen partial pressures above about 2e-6 Torr because lithium preferentially produces LiO over elemental Li. In some cases, it may be advantageous to operate at oxygen partial pressures above about 2e-6 Torr and use one or more techniques to reduce the amount and / or effects of condensation (e.g., using a source with a heated open end or edge, as described further herein). sLi rThe O precursor can be used, for example, to grow Li2O or LiGaO2 films.

[0088] Referring now to FIG. 16A, a plot 1600 of expected oxide condensation at the outlet of a binary oxide vapor source operating in a molecular oxygen-containing environment versus outlet temperature is shown, according to some embodiments. The y-axis, ΔP, is the partial pressure difference, which represents the sum of the equilibrium partial pressures of all Ga-containing (or Group III-containing) gas-phase species in the environment. ΔP is therefore a measure of the loss of Ga vapor (or Group III vapor) to the solid phase. In other words, ΔP is the rate at which the GaO precursor (or Group III precursor) is converted to GaO (or a Group III oxide, e.g., Al) in the presence of an oxygen reactant. x Ga 1-x ΔP is a measure of the driving force for the formation (or condensation) of a solid binary oxide (e.g., β-GaO). A positive ΔP indicates that the group III element (e.g., Ga or Al) is being removed from the vapor and incorporated into the solid binary oxide (e.g., β-GaO). In contrast, a negative ΔP indicates conditions where gas-phase Ga exceeds solid uptake, indicating etching conditions of the group III element (e.g., Ga or Al) from the solid group III oxide layer or liquid Ga droplet formation. ΔP acts like a chemical potential imbalance; the greater the difference between the amount of gallium (Ga) supplied and the amount remaining in equilibrium in the gas phase, the stronger the driving force for growing solid binary oxide crystals.

[0089] The x-axis of Figure 16A shows the temperature at the edge, or near or at the open end, of the binary oxide vapor source. Plot 1600 shows that when the edge is above a certain temperature, there is less of a driving force for solid oxide material to condense on the source. A binary oxide source with a heated edge (as described herein) can be beneficial in limiting or preventing the deposition or formation of solid oxide material at the edge, thereby limiting or preventing material from clogging the source opening.

[0090] 16B, a plot 1602 is shown of modeled expected GaO condensation at the outlet of a GaO binary oxide vapor source operating in different oxygen environments versus outlet temperature, according to some embodiments. The y-axis is ΔP, and the x-axis represents the temperature at the edge (or open end) of the binary oxide vapor source. In this example, the input GaO precursor partial pressure is 1e-6 Torr. Plot 1602 shows that there is little driving force for solid oxide material to condense at the source exit opening when the edge temperature exceeds approximately 880°C for the O (gas) reactant, or approximately 930°C for the O (gas) reactant, or 1010°C for the oxygen plasma reactant.

[0091] Plot 1602 is a plot of the thermodynamic reaction at the edge or exit opening of the source, showing that for certain edge temperatures, material formation at the tip is inhibited. This is because the increased temperature limits quenching of the reaction between the binary oxide precursor and molecular oxygen. Thus, in some cases, the edge may be heated to a higher temperature than other regions of the source (as further described herein), making it thermodynamically unfavorable for oxide condensates to form at or near the edge or exit opening. Plot 1602 shows that heating the source exit opening (or edge) to a different (e.g., higher) temperature than the base (or bulk) of the source is one way to increase the partial pressure of the binary oxide precursor at the outlet of a binary oxide vapor source, which can limit the deposition of solid binary oxide when oxygen partial pressure is applied in the chamber.

[0092] Referring now to FIG. 16C, a plot 1603 of a modeled thermodynamic process of the driving force (ΔP) for reacting InO (gas) with O to form InO solid is shown. In this model, the driving force is shown on the y-axis, and the O ratio, which is the partial pressure of O divided by the partial pressure of InO (gas), is plotted on the x-axis. InO gas is consumed according to the reaction InO + xO = InO. Plot 1603 shows a thermodynamic calculation of the driving force for forming a solid oxide material at an input pressure of InO equal to 1e-6 Torr compared to the "O ratio" and temperature. At low temperatures below about 800°C and an O ratio equal to 1 (i.e., below the stoichiometric O ratio (where x = 1)), all of the incoming InO gas is consumed according to the above reaction. If the O2 ratio is increased to a value greater than 1 (e.g., if x>1), there is an excess, or overpressure, or background, of O2, and no further increase in delta P (or growth rate of the In2O3 film) occurs.

[0093] Plot 1603 shows a series of modeled curves representing the temperature (e.g., at the output aperture of a binary oxide source, or at a substrate on which an oxide layer is deposited) from 850°C to 950°C in 25°C increments. The curves in plot 1603 show that the driving force for creating solid In2O3 drops dramatically with increasing temperature. The curves in plot 1603 also show that a higher O2 ratio can significantly increase the driving force for solid oxide formation, especially at higher temperatures. In some cases, the temperature at the output aperture of the binary oxide source can be increased to prevent or limit solid oxide deposition, especially when higher O2 ratios (e.g., greater than 1 or greater than 2) are used. In some cases, the O2 ratio can be increased to a value greater than 1 (e.g., greater than about 1.5, greater than about 2, or greater than about 2.5) to increase the driving force for creating a solid In2O3 layer and the growth rate, especially when higher temperatures (e.g., greater than 850°C) are used.

[0094] In some cases, an InO suboxide source can be placed in an ambient O environment, and the creation of solid InO can be suppressed by selecting a sufficiently high temperature at the exit orifice or aperture to reduce solid InO deposition and accumulation thereon. For example, the suboxide sources (i.e., binary oxide sources) described herein can be utilized with reactive oxygen species, such as atomic O or O (which decomposes to produce atomic O), to produce solid oxide materials (e.g., oxide layers on solid substrates). The cracking efficiency of atomic oxygen (e.g., RF-generated atomic oxygen) is low, ranging from about 1% to about 10%. Therefore, in addition to the reactive oxygen species required for growth, large amounts of O may be present in the deposition chamber. A high background concentration of O in the chamber can react with the suboxide source and deposit solid oxide on the suboxide source. This can alter the beam profile and / or uniformity and potentially block some or all of the suboxide source's exhaust outlets.

[0095] Referring now to FIG. 16D, a plot 1604 of the modeled thermodynamic driving force for three suboxides, or binary oxide precursors, MeO species (where Me = (In, Ga, or Al)) is shown. Plot 1604 shows examples of MeO solid formation for two "O ratios" (a stoichiometric O ratio of 1 (solid curve) and an O excess condition (dotted curve) where the O ratio is 3) versus temperature (x-axis). Plot 1604 shows that a high temperature roll-off (or reduction in driving force) occurs at high temperatures due to the excess O. Similar calculations can be performed, and curves similar to those shown in plot 1604 can be generated for other suboxides, or binary oxide precursors, species described herein, such as GeO, BO, BO, and the like. X , and can also be plotted for SiO. Similar modeling can also be done to simulate etching conditions, where the driving force (ΔP) is less than zero.

[0096] Referring now to FIG. 17, there is shown a diagrammatic representation of a binary oxide vapor source 1700 including a multi-zone (two-zone) heating configuration 1720 for differentially heating regions of the binary oxide vapor source, according to some embodiments.

[0097] In this example, the vapor source 1700 is similar to the vapor source 600 shown in FIG. 6A. However, instead of a heating arrangement including a single heating zone 620 (see FIG. 6A), the vapor source 1700 includes a heating arrangement including a two-zone heating arrangement 1720 with two separately controllable heater zones 1720A, 1720B, which differentially heats the vapor source 1700 to different temperatures at different locations along the length of the vapor source 1700. The heater zones 1720A, 1720B can include resistive heaters, radiative heaters, or any type of heater capable of providing heat to the source 1700. For example, in some cases, the crucible is at least partially within a vacuum chamber, such that there is a vacuum gap between at least some of the heater zones 1720A, 1720B and the vessel 602. In such cases, at least some of the heater zones 1720A, 1720B are radiative heaters that radiatively transfer heat to the vessel 602 through the vacuum gap.

[0098] In this example, the heating arrangement comprises two zones: a first heater zone 1720A heats the base region, including most of the wetted and semi-wetted regions, to drive the thermodynamic reaction to create the binary oxide precursor, and a second heater zone 1720B heats the tip region (e.g., in combination with the modeling results shown in FIG. 16) to reduce or prevent condensation of the solid oxide material.

[0099] 18A is a diagram of a binary oxide vapor source 1800 including a multi-zone heating configuration 1820 for differentially heating regions of the binary oxide vapor source, according to some embodiments. This example includes three heating zones.

[0100] In this example, vapor source 1800 corresponds to vapor source 600 shown in FIG. 6A or vapor source 1700 shown in FIG. 17. However, instead of a heating arrangement including a single heating zone 620 (see FIG. 6A) or two heating zones 1720A, 1720B, vapor source 1800 includes a heating arrangement 1820 including a three-zone heating configuration including three independently controllable heaters 1820A, 1820B, 1820C, which allows vapor source 1800 to be heated differently at different locations along its length, each heated to a predetermined temperature for better control of the thermodynamic reactions driving the creation of the binary oxide precursor. The additional control provided by the three independently controllable heaters 1820A, 1820B, 1820C can be beneficial, for example, for independently controlling the temperatures of the elemental materials in region 612 and reaction (e.g., semi-wet) region 614. For example, the temperature of the elemental material can be controlled using heater 1820A to evaporate or sublimate at a specific rate to become a solid or liquid, while heater 1820B can be used to independently control the temperature within reaction zone 614 and drive the formation of a specific species of binary oxide precursor. Again, heater 1820C can be additionally used to heat the open end or tip of the source, for example, to prevent condensation and blockage. Heaters 1820A, 1820B, and 1820C can include resistive heaters, radiative heaters, or any type of heater capable of providing heat to source 1800. For example, in some cases, the crucible is at least partially within a vacuum chamber, resulting in a vacuum gap between at least a portion of heaters 1820A, 1820B, and 1820C and vessel 602. In such cases, at least a portion of heaters 1820A, 1820B, and 1820C are radiative heaters that radiatively transfer heat to vessel 602 through the vacuum gap.

[0101] In some cases, heaters 1820A, 1820B, 1820C are collar-like shapes arranged concentrically around the region of source 1800. For example, source 1800 can have a generally cylindrical shape, and heaters 1820A, 1820B, 1820C can have annular cross-sections. In another example, source 1800 can be shaped like a prism with a generally rectangular cross-section, and heaters 1820A, 1820B, 1820C can have a generally rectangular annular cross-section.

[0102] In some cases, the binary oxide source can include more than three zones (e.g., four zones, six zones, or ten or more zones). For example, separate heating zones can be arranged in layers (e.g., as shown in FIG. 18A), and there can be four, or six, or more than six layers to more precisely control the temperature and temperature gradients within each region 612, 614, and 616 of source 1800. In some cases, separate heating zones can be arranged in layers (e.g., as shown in FIG. 18A), with each layer including a separately controllable heating zone centered around the periphery of source 1800.

[0103] 18B shows a simplified schematic diagram of a cross section 1801 of a source 1800 taken along a plane 1820, according to some embodiments. The insert 1820 illustrates an example in which the first wetting region 612 (where the solid binary oxide member is immersed in the liquid elemental component) includes four heaters 1820D distributed circumferentially around the cylindrically shaped source 1800. In some cases, the source 1800 can include more than three heating zone layers, each of which can include a separately controllable heater. Such an arrangement can be beneficial, for example, when the source 1800 is mounted in a system at an angle (e.g., as shown in FIG. 8B). In such cases, the elemental component liquid level can be at any angle relative to the central axis 1803 of the source. Thus, a source 1800 having an arrangement including separately controllable heaters (both in depth and circumferentially) can be beneficially used to heat specific regions of the source 1800 containing specific components (e.g., components having a liquid element component at any angle relative to the central axis) to a first temperature. Additionally, a second region (e.g., a region without a liquid element component) can be heated to a different second temperature, and yet another third region (e.g., a region at or near the edge) can be heated to yet another third temperature.

[0104] Figure 18C shows a simplified schematic diagram of a cross section of an example binary oxide precursor source 1805, according to some embodiments. The source 1805 is mounted at an angle, as in the system shown in Figure 8B, so that the liquids 1840 and 1842 are at an angle relative to the central axis 1803 of the source. Heaters 1820E-1820J are arranged in three layers, similar to heaters 1820A-1820C shown in Figure 18A. Heaters 1820E-1820J cover only half of the source 1805 rather than the entirety, and are independently controllable. The heaters in source 1805 have different lengths, with heaters 1820E and 1820F being longer than heaters 1820G and 1820H. As the liquid elemental components are consumed through the formation of the binary oxide precursor, the liquid level drops from level 1840 to 1842. In some cases, the temperature of the heaters may be adjusted over time, for example, to account for changes in the amount and level of the liquid element component. For example, when the liquid level is high, as indicated by liquid element component level 1840, heaters 1820E, 1820F, and 1820H may be set to a temperature corresponding to the temperature of the liquid element component. When the level of the liquid element component drops to 1842, heater 1820F, or heaters 1820E and 1820F, may be set to a temperature corresponding to the temperature of the liquid element component.

[0105] Each heater for the binary oxide sources shown herein (e.g., FIGS. 6A and 17-18C) can have its own thermocouple so that it can be separately controlled using a controller coupled to the thermocouple and heater. The thermocouples can be mounted within regions 612, 614, 616, or between heaters 1820A, 1820B, 1820C, and optionally 1820D, and vessel 602, or can be mounted on surfaces toward or away from vessel 602, and a feedback loop can be used to maintain the temperature of heaters 1820A, 1820B, 1820C, and optionally 1820D.

[0106] In some cases, the binary oxide sources described herein (e.g., binary oxide sources 850, 1700, 1800, 1805, and 1900) may be coupled to one or more sensors (e.g., sensor 855 in FIG. 8A), and the binary oxide source can be controlled using closed-loop feedback based on information from the sensor(s). The binary oxide source can be coupled to a processor used to control the source. The processor can also be coupled to one or more sensors and used to control the binary oxide source using information from the sensor(s). For example, the sensor can be an RGA or BFM, and the processor can control the temperature setpoint of one or more heater zones of the binary oxide source to maintain or target the binary oxide precursor flux measured by the sensor. In this example, the processor controls the temperature setpoint using information from the RGA and / or BFM sensor(s), and the processor can also control one or more heaters of the binary oxide source using information from the thermocouples. This can be advantageous because the flux of precursor species can vary over time, and the active closed-loop feedback described above can improve flux stability, thereby providing improved control over the composition, thickness, and / or material quality of the film being grown.

[0107] In some cases, the heater zones of the binary oxide sources described herein can be controlled to target specific compositions or ratios of species emitted from the source using closed-loop feedback based on one or more sensors. For example, an RGA can be used to determine the ratio of elemental species to binary oxide precursor species in the environment by controlling heaters in a zone containing the liquid elemental components and in a zone where the vapor of the elemental components reacts with the solid material in the source.

[0108] The steam sources 600, 1700, and 1800 shown in Figures 6A, 17, 18A, and 18B illustrate side cross-sectional views of the sources, which may be cylindrical or rectangular in shape in different embodiments. In such cases, the heaters 620, 1720A, 1720B, 1820A, 1820B, and 1820C may be shaped like cylindrical or oval rings around the source. Also, the heaters 1720A, 1720B, 1820A, 1820B, and 1820C in the multi-zone systems of Figures 17, 18A, and 18B may be longer or shorter than shown in the illustrated embodiments, resulting in longer or shorter temperature zones for the steam source.

[0109] In another embodiment, differential pumping of the growth chamber may be used, where the inlet of the vacuum pumping system is positioned proximal to the outlet opening of the binary oxide precursor source, thereby reducing the O partial pressure in this region to be lower than the average oxygen partial pressure in the growth chamber.

[0110] Referring now to FIG. 19 , a binary oxide vapor source 1900 including a condensation reduction arrangement 1990 is shown, according to some embodiments. In this example, the condensation reduction arrangement 1990 is configured to introduce an inert carrier gas into the vapor source 1900 at a partial pressure sufficient to flow out an open end 1950 of the vapor source 1900, forming a curtain or region 1995 of inert gas at the open end 1950 to displace molecular oxygen or any other active oxygen species that react with the binary oxide precursor to form oxide condensates. As a result, the condensation reduction arrangement 1990 can prevent or substantially reduce the formation of any oxide aggregates. Such a carrier gas curtain can also prevent species (e.g., molecular oxygen or any other active oxygen species) from entering the source through the opening(s) at the open end 1950. In this example, the inert carrier gas is introduced by an inlet manifold 1991, which includes one or more inlets for delivering the inert gas into the vapor source 1900 at the required partial pressure. In some cases, the inlet of the condensation reduction arrangement 1990 is located in the second region and / or third region (as described herein) of the source above the level of the liquid elemental component, allowing a carrier gas to be introduced into the voids of the solid binary oxide member.

[0111] In some cases, the inert gas is nitrogen (N). In another example, the inert gas is argon (Ar). As will be appreciated, any other suitable non-reactive or inert gas or inert gas mixture may be used as the carrier gas depending on the requirements. As an example, the use of Ar may be beneficial in some embodiments given the relative weight of this gas, resulting in a curtain or region 1995 of inert gas remaining near the open end 1950 of the vapor source 1900.

[0112] One or more inlets of the inlet manifold 1991 are shown on the sidewall of the steam source 1900 in Figure 19. In other cases, the inlets may be located at other locations on the steam source 1900. For example, one or more inlets may be positioned at or near the closed end 1960 or the open end 1950 of the steam source 1900.

[0113] In some cases, the binary oxide vapor sources described herein can be used as remote sources in physical vapor deposition (e.g., MBE) or chemical vapor deposition (e.g., MOCVD) systems. In such cases, it may be beneficial to use a carrier gas (e.g., an inert gas such as nitrogen or argon) to transport the generated binary oxide vapor precursor from the binary oxide vapor source to a growth chamber (e.g., a vacuum chamber or a quartz tube furnace). The inlet manifold 1991 in FIG. 19 can be used to introduce a carrier gas into the source 1900 to transport the generated binary oxide vapor precursor from the open end 1950 of the source 1900 to the growth chamber (e.g., connected to the source using a conduit).

[0114] Referring now to FIG. 20 , a system schematic diagram of a deposition system 2000 including a binary oxide remote vapor source 2050 and an active oxygen-containing species source 2060 for depositing an oxide layer on a substrate 2020 is shown, according to some embodiments. The substrate 2020 may optionally be rotating, as indicated by the arrows in the diagram. At higher pressures (e.g., greater than 1e-4 Torr), the precursor produced from the binary oxide vapor source 2050 and the active oxygen-containing species 2060 are mixed together in a growth chamber 2010. The growth chamber 2010 may be configured such that the binary oxide precursor 2052 (optionally mixed with a carrier gas) reacts with the active oxygen-containing species 2060 to form an oxide layer on the substrate 2020, which is typically heated during the deposition process, as indicated by arrow 2025. For example, a resistive heater or a radiative heater may be used to heat the substrate 2020. A pump 2015 is connected to the growth chamber 2010 and removes unreacted species, carrier gases, and other gases from the chamber.

[0115] 21 , a system schematic diagram of a flow-through furnace type deposition system 2100 including a binary oxide remote vapor source 2150 and an active oxygen-containing species 2160 for depositing an oxide layer on substrates 2120 a and 2120 b is shown, according to some embodiments. The deposition system 2100 further includes a growth chamber 2110, which can be at a pressure below, about, or above atmospheric pressure. In some cases, the growth chamber 2110 is or can include a quartz tube. In this example, a mixer 2180 is used to mix a carrier gas 2170 with the binary oxide precursor 2152, and the carrier gas 2170 is used to carry (or transport) the binary oxide precursor 2152 from the binary oxide remote vapor source 2150 to the growth chamber 2110. Within the growth chamber 2110, the binary oxide precursor 2152 reacts with the active oxygen-containing species 2160 to form an oxide layer on the substrates 2120 a and 2120 b. These are typically heated (arrow 2125) during the deposition process. In some cases, source 2150 can be similar to source 1900 shown in FIG. 19 , where a carrier gas is input to source 2150 to transport the binary oxide precursor from source 2150 to chamber 2110. In such cases, mixer 2180 may be omitted. A pump is coupled to growth chamber 2110 and can remove unreacted species, carrier gas, and other gases 2190 from the chamber. In this example, binary oxide vapor source 2150 is configured to be remote from growth chamber 2110 (i.e., located outside and / or spaced apart from the growth chamber), and this example includes a carrier gas arrangement to assist in transporting binary oxide precursor 2152 from binary oxide vapor source 2150 to growth chamber 2110.

[0116] In some cases, relatively high pressures (e.g., greater than 1e-4 Torr) are used in the growth chamber 2110. In some cases, the high pressure results in gas-phase reactions that result in the formation of solid oxide particles (or powder) in the growth chamber 2110. The temperature of the substrates 2120a and 2120b can be elevated in order to accommodate the formation of particles (or powder) and to grow high-quality binary oxide films.

[0117] In some cases, the binary oxide precursor 2152 and the active oxygen-containing species 2160 are introduced into the chamber 2110 at different locations that are spatially separated from one another to limit their interaction within the gas-phase environment of the chamber. For example, the active oxygen-containing species 2162 can be introduced into the chamber closer to the substrates 2120a, 2120b than the binary oxide precursor 2152 to limit reaction therebetween.

[0118] In some cases, the binary oxide precursors described herein can be used as a replacement for conventional metal-organic precursors, for example, in MOCVD and ALD systems and methods. This can be advantageous because the binary oxide precursors described herein can enable the growth of epitaxial layers with lower impurity levels than conventional (e.g., carbon-containing) metal-organic precursors. Without being limited by theory, it is believed that while conventional metal-organic precursors tend to incorporate some of their non-metallic elements (e.g., carbon) into the growing layer, the binary oxide precursors described herein contribute only metal and oxygen to the growing crystal.

[0119] FIG. 22 is a flowchart of a method 2200 for generating a binary oxide vapor precursor. The binary oxide precursor can be used in a deposition process in which a layer of oxide material is deposited on a heated substrate by reacting the binary oxide vapor precursor with an activated oxygen-containing species (e.g., an oxygen plasma containing atomic oxygen and / or one or more activated forms of oxygen), thereby forming a solid binary oxide layer on the substrate. In some cases, the deposited oxide material is the corresponding solid binary oxide form of the binary oxide. For example, the deposition process can be performed using a molecular beam epitaxy (MBE) machine, and the binary oxide vapor precursor can be generated using the MBE machine's sources. In other examples, the binary oxide vapor precursor can be used in a deposition process performed by another epitaxial growth technique, such as molecular-organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), or the like.

[0120] The articles, systems, and methods of the present invention utilizing the binary oxide vapor precursors described herein can be advantageous, for example, for increasing the growth rate of deposited materials. For example, the deposition rate of epitaxial oxide materials (e.g., in MBE, MOCVD, or ALD processes) can be increased using the binary oxide vapor precursors described herein. Conventional epitaxial oxide deposition in MBE systems utilizes one or more elemental beams and an activated oxygen source (e.g., an oxygen plasma source). In contrast, the binary oxide vapor precursors described herein can provide a higher oxygen flux than conventional activated oxygen sources (e.g., oxygen plasma sources). Oxygen flux is the limiting reactant for forming epitaxial oxide materials in conventional epitaxial growth systems (e.g., MBE), and therefore, the high oxygen flux enabled by the binary oxide vapor precursors described herein can enhance the growth rate of epitaxial oxide materials (e.g., in MBE systems and other epitaxial growth systems).

[0121] In some cases, the articles, systems, and methods of the present invention can be used in a deposition system (e.g., an MBE system) where the binary oxide vapor precursors described herein are utilized in combination with one or more elemental beams, and optionally, an activated oxygen source (e.g., an oxygen plasma source), to grow the epitaxial oxide materials described herein. For example, the one or more elemental beams can be a metal element beam or a beam of another element that reacts with oxygen to form the oxide material.

[0122] A method 2200 for producing a binary oxide vapor precursor includes blocks 2210, 2220, and 2230. In block 2210, elemental components corresponding to non-oxide components of the binary oxide vapor precursor to be produced are contained in an open-ended vessel including a closed end and a vessel wall extending from the closed end to the open end.

[0123] 23A-23B show an example of a vessel 2310 (alternatively referred to as a crucible or vessel) having a shape that can be used in the binary oxide vapor source of the present disclosure, according to some embodiments. The component 2316 (e.g., a liquid component, an elemental component, or a mixture of an elemental component and a solid binary oxide member) is shown in the figure at a level at an arbitrary angle (approximately 40°). For example, the source can be integrated into a vacuum chamber (as described further herein) and positioned at an arbitrary angle to direct the emitted beam toward a substrate within the chamber (e.g., in a system such as system 802 in FIG. 8B). In other cases, the vessel 2310 can be used as a vessel within a remote source (described further herein); in those cases, the vessel can be oriented vertically or at an arbitrary angle. The vessel 2310 has a generally cylindrical shape with a closed end (approximately z=0) and an open end (approximately z=100). The vessel 2310 also has a narrowed region 2312 toward the open end, which widens into a cone 2314 at the open end. In other cases, the vessels for the binary oxide precursor sources described herein may be taller or shorter, and wider or narrower than the vessel 2310 shown in Figures 23A-23B.

[0124] 23C-23D show another example of a container 2320 (or crucible) having a shape that can be used in the binary oxide vapor source of the present disclosure, according to some embodiments. The components 2326 (e.g., liquid components, elemental components, and mixtures of elemental components and solid binary oxide members) are shown in a horizontal level view that results when the container is used upright as shown in the figure. For example, the source can be integrated into a vacuum chamber (described further herein) or used as a container in a remote source (described further herein) and positioned upright. The container 2320 is generally conical in shape, with a rounded (blunt) bottom at the closed end (approximately z=0). The container 2320 has a wide opening toward the open end (approximately z=100).

[0125] 23A-23D both have shapes with relatively wide openings at the open ends, which can be beneficial, for example, to prevent blockages. The shape of the container can also contribute to (or determine) the spatial distribution of the beam flux emitted from the sources described herein. In some cases, binary oxide vapor sources of the present disclosure can include containers 2310 and 2320 and aperture plates, as shown, for example, in FIGS. 6B and 6C.

[0126] Vessels 2310 and 2320 are just two examples of vessel geometries that may be used in the binary oxide vapor sources described herein, and in some embodiments, other vessel geometries may be used, such as vessel 2310, having wider or narrower constricted regions and openings at the open ends.

[0127] Continuing with method 2200, at block 2220, one or more solid binary oxide components are introduced into the open-ended vessel to form an encapsulated aggregate structure of the binary oxide components within the vessel wall and the closed end of the open-ended vessel, each of the one or more solid binary oxide components corresponding to a solid binary oxide stoichiometric form of the binary oxide vapor precursor being produced.

[0128] In one embodiment, the binary oxide member is in the form of an elongated rod that extends partially or completely along the vessel.

[0129] In one embodiment, the binary oxide members are in the form of spheres of constant diameter.

[0130] In one embodiment, the binary oxide members are in the form of spheres of various diameters.

[0131] In one embodiment, the binary oxide member is in the form of a cylinder or pellet of a fixed diameter and length.

[0132] In one embodiment, the binary oxide members are in the form of cylinders or pellets of various diameters and lengths.

[0133] In one embodiment, the binary oxide member is in the form of a solid spheroid of a certain dimensional size.

[0134] In one embodiment, the binary oxide members are in the form of solid spheroids of various dimensional sizes.

[0135] In one embodiment, the binary oxide member is in the form of an amorphous solid of substantially uniform dimensional size.

[0136] In one embodiment, the binary oxide member is in the form of a substantially amorphous solid of various dimensional sizes.

[0137] In some cases, the binary oxide member may be in the form of one or more of an elongated rod extending partially or completely along the vessel; a sphere of constant diameter; a sphere of varying diameter; a cylinder or pellet of constant diameter and length; a cylinder or pellet of varying diameter and / or length; a solid ellipsoid of constant dimensional size; a solid ellipsoid of varying dimensional size; an irregularly shaped solid of substantially constant dimensional size; and an irregularly shaped solid of varying dimensional size.

[0138] In another example, the sizes of the binary oxide elements are selected from a predetermined size distribution. For example, the size distribution can be approximately normal, Gaussian, monomodal, or multimodal. In some cases, the binary oxide element includes multiple elements (e.g., particles, granules, spheres, rods, etc.) having a bimodal or multimodal size distribution (e.g., a mixture of small and large particles to improve packing density).

[0139] In another example, the individual binary oxide components may be selected from any of the examples mentioned above.

[0140] In one example, the elemental components are in liquid form, the density of the binary oxide member is greater than the density of the elemental components in liquid form, and the contained aggregate structures are fully or partially immersed in the liquid elemental components.

[0141] In one example, the elemental components are in liquid form and the contained aggregate structures include binary oxide members dispersed throughout the liquid elemental components.

[0142] In one example, the density of the binary oxide member is less than the density of the elemental component in liquid form, and the contained aggregate structure comprises the binary oxide member dispersed on the surface of the liquid elemental component.

[0143] In one example, the contained agglomerated structures are closely packed columns of binary oxide members that extend along a portion of the length of the open-ended vessel (from the closed end along the open end).

[0144] Figure 24 shows an encapsulated aggregate structure comprising columns of closely packed solid ellipsoidal binary oxide elements of sizes selected from a predetermined size distribution, which can be used, for example, in vessel 2310 of Figure 23A. The size distribution and shape(s) of the binary oxide elements can also affect various attributes such as porosity and interaction length.

[0145] In another example, the contained aggregate structure is a single binary oxide member (eg, one that is porous or has holes or spaces through which gas can pass).

[0146] In one example, the encapsulated aggregate structure is configured to have a predetermined packing density.

[0147] In one example, the encapsulated agglomerate structure is configured to have a surface area (eg, a predetermined and / or specific surface area) that characterizes the total surface area of ​​the encapsulated agglomerate structure.

[0148] In one example, the amount of elemental component introduced relative to the amount of binary oxide member is selected to satisfy the minimum amount required for one or more solid binary oxide members to fully react with the elemental component to produce the binary oxide precursor. In another example, the amount of elemental component introduced relative to the binary oxide member is selected to satisfy the minimum amount required for one or more solid binary oxide members to fully react with the elemental component to produce the binary oxide precursor.

[0149] 22, at block 2230, the elemental components are heated in a container until they are in liquid form. Vapors of the elemental components can evaporate from the liquid and migrate (e.g., via diffusion or transported by a carrier gas) toward the open end of the open-ended container. As the elemental component vapors migrate toward the open end, they can react with the encapsulated aggregate structures of one or more solid binary oxide elements to produce binary oxide vapors.

[0150] 22, block 2210 can occur temporally before block 2220, or block 2220 can occur temporally before block 2210. In other words, the elemental components can be added to the open-ended vessel either before or after the binary oxide members. Generally, when heated, the relative densities and shapes of the binary oxide members affect the buoyancy of the binary oxide members in the elemental components.

[0151] GaO (蒸気)

[0152] In an exemplary application, a method for producing a binary oxide vapor precursor described herein (e.g., method 2200 of FIG. 22) can be employed to produce Ga according to the following chemical reaction: (蒸気) (i.e., elemental component vapor) into a solid GaO material (i.e., GaO (蒸気) (the stoichiometric form of the solid binary oxide of Ga) 2O(蒸気) may be generated. GaO 3(固体) +4Ga (蒸気) →3Ga2O (蒸気) formula 2

[0153] In the example above, Ga has a low melting temperature and forms a liquid when heated. (蒸気) is formed from the liquid (e.g., by evaporation), and the vapor elemental components migrate toward the open end of the container and react with the GaO material enclosed within the container, forming GaO (蒸気) Form.

[0154] Referring now to FIG. 25, the corresponding amount of Ga (grams) reacts completely to form GaO as shown by line 2510. 蒸気2500 is shown illustrating the amount of GaO needed to form elemental GaO. Thus, in some cases, for a given amount of Ga, selecting an amount of GaO above line 2510 (i.e., within region 2530) results in an excess of GaO in the container relative to elemental Ga. On the other hand, if an amount of GaO is selected below line 2510 (i.e., within region 2540), an excess of elemental Ga in the container relative to GaO is produced. In this example, upon heating, GaO and Ga vapor are produced within the container. The geometry of the open-ended container, the interaction time and available surface area of ​​the binary oxide members, and other factors can affect the concentrations of Ga and GaO in the vapor within the container and the concentration of the vapor exiting (or released) from the container. In some cases, the concentration of GaO vapor is much higher than the concentration of Ga vapor within the container and the concentration of the vapor exiting (or released) from the container upon heating. The vapor pressure of elemental Ga is much lower than that of Ga2O3, and therefore the concentration of Ga2O in the vapor is often much higher (e.g., 10 or 100 or 1000 or more times) than the concentration of Ga vapor. If the amount of elemental Ga in the crucible is much larger (e.g., 10 or 100 or 1000 or more times), the concentration of elemental Ga in the vapor can be similar to or greater than the concentration of Ga2O in the vapor.

[0155] Solid binary oxide elements can be of varying densities depending on their formation. Table 1 below shows the densities of some example forms of solid Ga2O3. However, at elevated temperatures, such as those used during source operation, the density may be different. [Table 1]

[0156] In this example, Ga (液体) is 6.095g / cm 3 In some cases, Ga2O3 in granular or rod form can have a density of Ga (液体)In the absence of any supporting arrangement, Ga2O3 in the bulk form of a single crystal wafer will "float" on the Ga (液体) Note that the temperature sinks.

[0157] 26A-26C show GaO (蒸気) An example is shown in which Ga and Ga2O3 granules are added to a crucible to produce

[0158] 26A shows an open-ended vessel in the form of a conical-shaped crucible 2600 including a closed end 2610 and a vessel wall 2620 extending from closed end 2610 to an open end 2630. In some cases, crucible 2600 can have an open end or orifice diameter of about 10 mm to about 100 mm, a rim diameter of about 12 mm to about 120 mm, a length of about 20 mm to about 500 mm, a closed end radius of about 2 mm to about 20 mm, and a capacity of about 10 cc to about 1000 cc.

[0159] In Figure 26B, Ga 2650 is contained in a crucible 2600. In this example, 50 g of Ga in the form of 8 mm diameter spheres can be used, which are first heated to form a Ga melt having a volume of approximately 8.2 cc. (液体 Depending on the shape of the crucible 2600, the Ga SiO 2 contained in the crucible 2600 in this example may be formed. (液体) Depth d Ga is about 10 mm to about 100 mm.

[0160] In Figure 26C, solid GaO particles 2680 in granular form (optionally with a size distribution) are introduced into the crucible 2600. 蒸気 / Ga (蒸気) Referring to the dividing line 2510, if the crucible 2600 contains 50 g of Ga, the amount of Ga2O3 is selected to be 33.9 g. (液体) A calculated fill volume of 13.5cc placed in the container and a depth of approximately 10mm to approximately 100mm (depending on the shape of the container)

number

[0161] As will be appreciated, in another example, Ga spheres and solid GaO (optionally having a size distribution) may be first mixed together. Upon initial heating, the Ga forms a liquid, and solid GaO members 2680 in granular form can settle onto the Ga layer in the crucible.

[0162] As will be appreciated, during operation, the crucible may be placed at an oblique angle relative to the axis of any associated growth chamber (e.g., MBE machine). Generally, in this example, where the solid binary oxide component is floating on top of the elemental component, increasing the angle of tilt will generally decrease the total amount of material that can be added to the binary oxide vapor source.

[0163] After addition to the crucible 2600 as described above, the crucible may be further heated to form Ga (vapor), (蒸気) moves toward the open end 2630 of the crucible and reacts with the packed column of GaO granules, forming GaO (蒸気) (see Equation 2).

[0164] GeO 2(蒸気)

[0165] In another exemplary application, a method for producing a binary oxide vapor precursor described herein (e.g., method 2200 of FIG. 22) can be used to produce Ge according to the following chemical reaction: (蒸気) (i.e., elemental component vapor) into a solid GeO2 material (i.e., GeO (蒸気) (stoichiometric form of the solid binary oxide of GeO)(蒸気) may be generated. GeO 2(固体) +Ge (蒸気) →2GeO (蒸気) Formula 10

[0166] Referring now to FIG. 27, the corresponding amount of Ge reacts completely to form GeO as shown by line 2710. (蒸気) 27. Illustrated is a plot 2700 illustrating the minimum amount of GeO2 required to form elemental GeO2. Thus, in some cases, for a given amount of Ga, selecting an amount of GeO2 above line 2710 (i.e., within region 2730) will result in an excess of elemental Ge in the container relative to GeO2. On the other hand, if an amount of GeO2 is selected from below line 2710 (i.e., within region 2740), there will be an excess of GeO2 in the container relative to elemental Ge.

[0167] To form liquid Ge, solid Ge must first be heated to a temperature of 938°C (or higher). At this temperature, solid Ge has a density of approximately 5.6 g / cm 3 It is also important to note that GeO2 itself has a melting point of 1115°C. This allows solid GeO2 to be used to produce GeO (蒸気) This sets an approximate upper limit to which the interior of any container can be heated to form a solid GeO2 body, again approximately 6 mm in size and approximately 4.3 g / cm3. 3 26A) with a density of 1000 MPa (GeO2 elements instead of Ga2O3 elements, as in FIG. 26A).

[0168] Using the crucible 2600 shown in FIG. 26A, for 50 g of Ge, the expected volume upon melting is 8.9 cc, resulting in a G e(液体) Depth d Ge The GeO shown in Figure 27 is 37.8 mm. 蒸気 / Ge (蒸気) Referring to the dividing line 2710, in FIG. 27, for 50 g of Ge contained in the crucible 2600, the amount of GeO2 is selected to be 72 g. (液体)A calculated fill volume of approximately 17 cc placed in the container and a depth of approximately 10 mm to approximately 100 mm (depending on the shape of the container)

number

[0169] AlO (蒸気) and SiO (蒸気)

[0170] In another exemplary application, the methods for producing binary oxide vapor precursors described herein (e.g., method 2200 of FIG. 22) can be employed to produce Al (蒸気) (i.e., elemental component vapor) into a solid Al2O3 material (i.e., Al2O (蒸気) AlO (蒸気) See, for example, Equations 4 and 4b.

[0171] In this example, Al has a melting point of about 665°C and a density of 2.375 g / cm in the liquid state. 3 This means that the density is approximately 4.0 g / cm 3 This may be contrasted with Al2O3 (sapphire), which in some cases, depending on the amount of Al2O3 material, a certain percentage of which may be submerged in liquid Al.

[0172] In another example, a method for producing a binary oxide vapor precursor described herein (e.g., method 2200 of FIG. 22) can be employed to produce Si (蒸気) (i.e., elemental component vapor) into a solid SiO2 material (i.e., SiO (蒸気) (the stoichiometric form of the solid binary oxide of (蒸気) See, for example, Equation 5.

[0173] 28A, a binary oxide vapor source 2800a is shown according to an exemplary embodiment. The binary oxide source 2800a includes a closed end 2820 and an open end 2810, a first region 2830, a second region 2850, and a space, where the first region 2830 is located adjacent the closed end 2820 and includes an elemental component 2840, the second region 2850 is located between the first region 2830 and the open end 2810 and includes a solid binary oxide component 2860, and the space allows elemental vapor from the first region 2830 to pass through. The elemental vapor reacts with the binary oxide material 2860 to produce binary oxide vapor, which exits the binary oxide vapor source 2800a through the open end 2810. In this example, solid binary oxide component 2860 of second region 2850 includes an aggregate structure, which in this embodiment is configured as granules of solid binary oxide component. In this example, solid binary oxide component 2860 has a lower density than elemental component 2840 and is therefore substantially or primarily distributed over elemental component 2840. Solid binary oxide component 2860 may be granules, a powder, or a porous solid material. In some cases, solid binary oxide component 2860 has a high surface area.

[0174] 28B, a binary oxide vapor source 2800b according to another exemplary embodiment is shown. This example is similar to the binary oxide vapor source 2800a shown in FIG. 28A, except that the density of the solid binary oxide component 2860 is greater than the density of the elemental component 2840, and therefore the solid binary oxide component 2860 precipitates within the elemental component 2840. In this case, the solid binary oxide component 2860 is distributed throughout both the second region 2850 and the entire elemental component 2840 in the first region 2830.

[0175] 28C, a binary oxide vapor source 2800c according to another exemplary embodiment is shown. This example is similar to binary oxide vapor sources 2800a and 2800b shown in FIGS. 28A and 28B, except that an intermixing region 2870 also exists between first region 2830 and second region 2850. For example, first region 2830 can include elemental component 2840 (but not binary oxide component 2860), second region 2850 can include binary oxide component 2860, and intermixing region 2870 can include both elemental component 2840 and binary oxide component 2860. In some examples, first region 2830 can include both elemental component 2840 and binary oxide component 2860, and second region can include only binary oxide component 2860, with the intermixing region including both elemental component 2840 and binary oxide component 2860. Such cases may occur, for example, when the densities of elemental component 2840 and binary oxide component 2860 are similar, or when geometric constraints prevent binary oxide component 2860 from sinking to the bottom of the crucible.

[0176] 29, a flow chart of a method 2900 for producing a binary oxide vapor precursor is shown, according to an example embodiment. In one example, the method 2900 may use a binary oxide vapor source according to Figures 28A-28C and other examples described in this disclosure.

[0177] At block 2910, the method 2900 includes providing a binary oxide vapor source having a closed end and an open end. The binary oxide vapor source also includes a first region located adjacent the closed end containing an elemental component, a second region located between the first region and the open end, and one or more spaces, wherein the second region contains a solid binary oxide component and the spaces allow vapor to pass through and react with the solid binary oxide component.

[0178] At block 2920, method 2900 includes heating the binary oxide vapor source to form an elemental vapor, which can pass through the space in the second region and react with the binary oxide material to produce a binary oxide vapor that exits the binary oxide vapor source through an open end. In some cases, the heating can be performed in multiple steps. For example, elemental components can be added to the source, and then a first heating can be performed to melt the elemental components. Solid binary oxide components can then be added to the source (e.g., after cooling the source), and the source can be heated a second time.

[0179] In one example, the binary oxide vapor source may be pre-loaded with elemental components in solid form, with the solid binary oxide components being added in particulate or granular form. For example, the binary oxide vapor source may be pre-loaded with elemental Ga components in the form of ingots (or flakes or similar forms) and solid binary oxide components in the form of GaO granules (or rods, or flakes, or powder). In some cases, Ga and / or GaO elements of different sizes may be used together in the crucible. Furthermore, in some cases, Ga and / or GaO elements of different forms may be added together in the crucible. For example, GaO elements in rod form may be added, and then GaO powder (i.e., elements smaller and differently shaped than the rods) may be added to fill the space between the rods. Using Ga and / or GaO elements of different sizes and / or forms may be advantageous, for example, to increase the packing density (or overall mass density) of the material in the crucible. The more material in the source, the longer the source can operate before being depleted.

[0180] In some cases, after initial heating of the binary oxide vapor source, a first region containing molten Ga is formed, and Ga2O3 "floats" on the molten Ga, forming a second region containing Ga2O3 located between the first region and the open end. In other cases, the density of the solid binary oxide component may be comparable to or less than that of the molten elemental component, and it may "sink" or partially sink into the molten elemental component. However, according to the present disclosure, depending on the morphology and amount of the solid binary oxide component, in either case, there may be a second region located between the first region and the open end that contains at least a portion of the solid binary oxide extending from the first region to the second region. In some cases, there may be an intermediate region between the first region and the second region, where the first region contains the molten elemental component and the second region contains the solid binary oxide component, and the intermediate region contains both the molten elemental component and the solid binary oxide component.

[0181] FIG. 30 illustrates an example of a binary oxide vapor source 3000c including a heating arrangement having a first heater zone 3080a and a second heater zone 3080b that transfer heat to a crucible 3020. The first heater zone 3080a and the second heater zone 3080b substantially correspond to the first region 2830 and the second region 2850 of the vapor source and can be separately controllable to heat the different zones at different temperatures. FIG. 30 illustrates a cross section of the binary oxide vapor source 3000c, where each of the heater zones 3080a-3080c can be shaped like a ring (e.g., a substantially circular ring, or a square or rectangular ring). In one example, the second heater zone 3080b, corresponding to the second region 2850, is heated at a higher temperature compared to the first heater zone 3080a to control condensation and reduce blockages. Condensation and blockages can be detrimental to a binary oxide vapor source because they can block the opening and alter the beam profile. In extreme cases, condensation and blockages can substantially affect the beam flux. FIG. 30 also illustrates an optional third heating zone, including a third heater zone 3080c, which is located closer to the open end 3010 of the binary oxide vapor source 3000c than the first and second heater zones 3080a and 3080b. The third heater zone 3080c is used to heat the crucible 3020 near the open end 3010 to a high temperature (e.g., greater than the temperature in the first zone 2830 and the second zone 2850), thereby helping to prevent condensation of vapor near the open end 3010 of the crucible 3020.

[0182] In other cases, the heater may have one heater zone 3080a and no second heater zone 3080b or third heater zone 3080c. In these cases, as shown in FIG. 30, the first heater zone 3080a may be within the first region 2830 or may extend higher into the second region 2850. In some cases, the first heater 3080a may extend through all of the first region 2830 and all of the second region 2850. In some cases, the first heater zone 3080a (as described above) may be used in conjunction with the third heater zone 3080c (heater zone 3080b may also be omitted), for example, to prevent condensation of vapors near the open end 3010 of the crucible 3000c.

[0183] Referring now to FIG. 31, a plot 3100 similar to FIG. 25 is shown showing two exemplary mass ratios 3110, 3120 of solid binary oxide component to elemental component that were evaluated for a binary oxide vapor source according to the present disclosure described below.

[0184] In this example, the solid binary oxide component includes Ga2O3, the elemental component includes Ga, and the Ga2O3 / Ga mass ratio on boundary line 3130 is 0.678.

[0185] A binary oxide vapor source containing elemental Ga and Ga2O3 solid granules

[0186] In the first experiment of this example, elemental Ga and GaO solid granules were added to a binary oxide vapor source (e.g., as shown in Figures 26A-26C, 28A, 28B, and / or 28C). Figure 31 shows a mass ratio 3110 of 0.793 in this example. This was achieved by first inserting two Ga ingots or rods, each weighing 25 grams, for a total of 50 grams of Ga. To this was added a total of 39.66 grams of GaO granules, which were poured in multiple steps over and around the Ga ingots. As can be seen from Figure 31, 39.66 grams exceeds the 33.9 g of GaO needed to completely convert elemental Ga to volatile GaO (i.e., ΔGaO = 5.76 grams).

[0187] In the second experiment of this example, a binary oxide vapor source was added containing solid particles of elemental Ga and Ga2O3 (e.g., as shown in Figures 26A-26C, 28A, 28B, and 28C) at an equivalent mass ratio of 0.938 of 3120, as shown in Figure 31. This was achieved by first inserting two Ga ingots or rods, each weighing 25 grams, for a total of 50 grams of Ga. To this was added a total of 46.9 grams of Ga2O3 granules, which were poured in multiple steps over and around the Ga ingots. As can be seen in Figure 31, this 46.9 gram amount exceeds the 33.9 g of Ga2O3 required to completely convert elemental Ga to volatile Ga2O (i.e., ΔGa2O3 = 13.0 grams). In contrast to the first experiment, the second experiment had a higher ratio of Ga2O3 to Ga.

[0188] In both experiments in this example, the Ga ingot or rod was cylindrical with a diameter of 8 mm and a length of 6 mm, and the GaO granules were roughly spherical with a diameter of about 3 mm. However, some of the GaO granules had a maximum diameter of about 8 mm. In other words, the GaO granules had a diameter distribution ranging from less than about 3 mm to more than about 8 mm, with a median (or average) diameter of about 3 mm. Ga melts at about 30°C, and the mass density of liquid Ga is 6.095 g / cm. 3, Ga2O3 granules, which have a melting point of approximately 1900 °C, are expected to remain solid at the temperatures used in most deposition processes. As mentioned previously, the mass density of Ga2O3 granules is approximately 2.5 g / cm 3 and in some cases, Ga2O3 granules may float on the surface of the molten Ga.

[0189] Figure 32 is a plot 3200 of the total volume of a Ga / Ga2O3 mixture as a function of the mass of Ga for the crucible geometry shown in Figures 26A-26C (i.e., a 60 cc crucible), according to one exemplary embodiment. Plot 3200 also shows total volumes 3210 and 3220 corresponding to the two exemplary loading regimes 3110 and 3120, respectively, mentioned above. The total volume is the sum of the volume of molten Ga and the volume of solid Ga2O3 granules. Volume 3230 corresponds to a mixture of 50 g of metallic Ga and 33.9 g of Ga2O3 granules, which corresponds to boundary line 3130.

[0190] The total volume 3230 of this mixture is approximately 22 cc, which corresponds to approximately 37.5% of the capacity of a 60 cc conical crucible. The dashed line 3240 indicates the full theoretical capacity of the crucible, although as mentioned above, the crucible mounting configuration (e.g., if the crucible is mounted at an angle) may need to be taken into account when determining the actual total fill volume fraction.

[0191] Figure 33 is a plot 3300 of measured GaO flux φ versus binary oxide vapor source temperature (single zone heater) for two examples from different sources using the different mass ratios mentioned in Figure 31 above. Example data 3310 corresponds to a GaO / Ga ratio of 0.793, and example data 3320 corresponds to a GaO / Ga ratio of 0.938. In this example, the flux is measured by a beam flux monitor (BFM) after the initial addition. The data show that the a coefficients (related to the activation energy of the reaction) fitted to the Arrhenius plots are similar. The different vapor source configurations for the two experiments in this example may have caused a slight offset in the pressure-temperature curves in Figure 33.

[0192] FIG. 34 is an Arrhenius plot 3400 of the natural logarithm of the GaO flux φ versus the reciprocal of the absolute temperature T (multiplied by 1000) of the binary oxide vapor source for the example experiment above, according to some embodiments. Example data 3410 corresponds to a GaO / Ga ratio of 0.793, and example data 3420 corresponds to a GaO / Ga ratio of 0.938. The fit coefficients and goodness of fit for both data sets are shown. The Arrhenius plot 3400 confirms the exponential dependence of the beam flux species occurring at relatively low temperatures, and thus, in this example, is entirely (or almost entirely) GaO vapor due to the much higher vapor pressure of GaO compared to Ga. The flux of elemental Ga can be more significant at temperatures approximately 150° C. higher. This confirms the thermodynamic reaction of Ga vapor, which functions to react or etch solid GaO to form a pure GaO emission flux.

[0193] FIG. 35 shows X-ray diffraction (XRD) 2q-w scans according to an exemplary embodiment of the present disclosure. Scan 3500 is of a first GaO film grown on a 2-inch sapphire wafer with a (0001) orientation 3510, and scan 3520 is of a second GaO film grown on a 2-inch 4H—SiC substrate with a (0001) orientation. In this example, both films were grown using a binary oxide vapor source with a GaO / Ga mass ratio of 0.793. Oxygen plasma was used to generate atomic oxygen. Both films are single-crystalline b-phase GaO with a (-201) orientation along the growth direction, as inferred from the presence of the Bragg peaks marked with arrows.

[0194] The arrow indicates the Bragg peak corresponding to the n(-201) plane family of the b-Ga2O3 structure, where n is an integer from 1 to 5. The other reflections in Figure 35 originate from the substrate. The data in plot 3500 indicate that the Ga2O3 film grew in a single phase and with a single orientation along the normal to the substrate surface.

[0195] The b-Ga2O3 film thicknesses mentioned in Figure 35 were measured by UV-Vis reflectance measurements across the 2-inch substrate. Both film thicknesses are in the micrometer range, with thickness uniformity of greater than 5% across the 2-inch wafer area.

[0196] Figure 36 is a UV-visible reflectance measurement thickness map 3600 of a b-Ga2O3 film grown on a c-plane sapphire substrate. The data shows that the thickness uniformity across the 2-inch substrate (excluding a 5 mm wide edge) is better than 4%.

[0197] Figure 37 shows a UV-visible reflectance thickness map 3700 of a b-Ga2O3 film grown on a 4H-SiC(0001) substrate. The data shows that the thickness uniformity across 2 inches (excluding a 5 mm wide edge) is better than 5%.

[0198] The thickness uniformity, or standard deviation of thickness divided by the average thickness, of the epitaxial oxide layers (or films) described herein may be between about 1% and about 10%, less than about 1%, less than about 2%, less than about 3%, less than about 4%, less than about 5%, or less than about 10%.

[0199] Growth of binary, ternary, and multicomponent oxides from binary oxide precursor sources

[0200] In some embodiments, two of the binary oxide vapor sources described herein can be used in conjunction with an active oxygen source to produce two binary oxide precursors, which can be used to form a ternary oxide material. For example, a first binary oxide vapor source can be used to produce GaO(vapor), and a second binary oxide vapor source can be used to produce AlO(vapor). GaO(vapor) and AlO(vapor) are introduced into a growth chamber from the two binary vapor sources along with active oxygen species from the active oxygen source and deposited on a heated substrate in the growth chamber. x G a1-xIt is possible to form an epitaxial film of SiO2 by the reaction: (x) AlO (気体) +(1-x)GaO (気体) +2O → (Al x Ga 1-x )2O 3(固体) Formula 11 Similarly, other three-dimensional oxide materials include In x Ga y O z , Ga x Si y O z , Al x Si y O z , Ga x Ge y O z , Al x Ge y O z (where x>0, y>0, and z>0) can be formed by combining different binary oxide vapor sources described herein. As noted above, the growth chamber can be a vacuum chamber or can be at atmospheric pressure. Some examples of deposition systems that can produce ternary materials using two binary oxide vapor sources are molecular beam epitaxy, CVD (e.g., MOCVD), and ALD.

[0201] In some cases, three or more binary oxide vapor sources described herein can be used in conjunction with an activated oxygen source to produce three or more binary oxide precursors, which can be used to form multi-element oxide materials (e.g., binary, ternary, quaternary, or quinary oxides, or oxide materials having six or more elements) within the growth chamber of a deposition system.

[0202] In some cases, the deposition system and associated sources and growth chamber are configured so that the binary oxide precursors react preferentially to form multi-element oxide materials on the heated substrate in the growth chamber, as described herein, rather than reacting in the growth chamber before reaching the substrate.

[0203] In some cases, the binary oxide precursors react in the growth chamber to form intermediate products before reaching the heated substrate, which can form multi-element oxide materials on the heated substrate (e.g., by reacting with activated oxygen, another binary oxide precursor, and / or the intermediate products).

[0204] 38 and 39 show a modeled example of using two binary oxide vapor sources in combination with an activated oxygen source to form a ternary oxide material, according to some embodiments. In this example, the ternary composition is (Al 0.5 Ga 0.5)2O3, and the reaction being modeled is similar to Equation 11, but with the concentration of active oxygen "y" varied (rather than fixing the value of active oxygen at 2 as in Equation 11). The plots in FIGS. 38 and 39 have a y-axis, ΔP, which is the change in partial pressure for the formation of the ternary oxide compound according to the reaction. As described herein, ΔP is a measure of the driving force for the formation of the ternary oxide material and can also be a measure of the growth rate of the ternary oxide material. Example data 3810 corresponds to a "y" value of 1.5, example data 3820 corresponds to a "y" value of 1.6, example data 3830 corresponds to a "y" value of 1.8, example data 3840 corresponds to a "y" value of 1.9, and example data 3850 corresponds to a "y" value of 2.0. These plots demonstrate that the amount of active oxygen provided directly affects the driving force ΔP and / or growth rate of the ternary oxide material. The driving force, ΔP, or growth rate of the ternary oxide material can be increased by increasing the amount of available oxygen up to the stoichiometric value of 2 (y=2). Beyond y=2, for temperatures between about 500°C and about 1400°C or 1600°C, ΔP (related to the driving force or growth rate of the ternary oxide material) remains approximately constant with increasing oxygen concentration or partial pressure. Furthermore, once the temperature exceeds about 500°C, the driving force, ΔP, or growth rate of the ternary oxide material remains relatively constant with temperature until the temperature reaches about 1400°C to 1600°C. At temperatures above about 1400°C to 1600°C, conditions begin to become unfavorable for the formation of the ternary oxide material from the binary oxide reactants, and the driving force, ΔP, or growth rate of the ternary oxide material decreases. The modeled situation in the plot of Figure 39 shows that when the partial pressure of oxygen is high (greater than y = 2), the reaction can be advantageously maintained at high temperatures (e.g., about 1500°C or 1600°C), thus enabling high growth rates of the ternary oxide material at high temperatures. Forming the ternary oxide material at higher temperatures can be advantageous, for example, to improve the crystalline quality of the ternary oxide material (e.g., to reduce the concentration of defects such as point defects). Example data 3910 corresponds to a "y" value of 2.0, example data 3920 corresponds to a "y" value of 2.1, and example data 3930 corresponds to a "y" value of 2.5.

[0205] In some cases, the binary oxide vapor sources described herein can be used to form oxide materials by reacting one or more of the binary oxide vapor precursors with activated oxygen and, for example, with an elemental or molecular beam from an evaporation source, gas source, or other type of source that can be used with a material deposition system.

[0206] FIG. 40 shows a schematic diagram of an example system 2400, including similar components as described with respect to system 800 shown in FIG. 8A, and further including an additional elemental or molecular source 4010 according to some embodiments. The elemental or molecular source 4010 can be coupled to the growth chamber 810 or can be configured as a remote source, as described herein. The elemental or molecular source 4010 can be a vapor source, such as a Knudsen cell used in conventional MBE. In some cases, the source 4010 can be a gaseous source, such as a metal-organic precursor source used in conventional MOCVD or ALD. In some cases, one or more of the binary oxide vapor sources 850 described herein can be used in conjunction with the activated oxygen source 860 and the elemental or molecular source 4010 to form multi-element oxide materials (e.g., binary, ternary, or quaternary oxides, or oxide materials having five or more elements) within the growth chamber of the deposition system.

[0207] In some cases, the binary oxide precursors and sources described herein (e.g., as shown in Figures 6A, 8A-8B, 17, 18A-18C, 19-21, 26A-26C, 28A-28C, 30, or 40) can be used in combination with elemental or molecular sources (as shown in Figure 40), which may be elemental atomic beams from conventional sources (e.g., Knudsen cells) or metal-containing organic precursors (e.g., in MOCVD or ALD system configurations using remote sources). For example, Ga and / or Al containing binary oxide precursor(s) and source(s) described herein may be used in combination with Zn, Mg, and / or Ni source(s) to form (Zn, Mg, Ni)-(Ga, Al)-O containing materials in epitaxial layers. For example, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source and optionally an additional metal-containing source to deposit the following epitaxial layers: GaO (e.g., α-phase or β-phase); x Ga 1-x )2O3 (e.g., α-phase or β-phase) (wherein 0≦x≦1); Mg x Ga 2(1-x) O 3-2x (wherein 0≦x≦1); Mg x Al 2(1-x) O 3-2x (wherein 0≦x≦1); (Mg x Zn 1- x) z (Al y Ga 1-y ) 2(1-z) O 3-2z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Zn x Ga y O z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Zn x Al y O z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Mg x Ga y O z(wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Mg x Al y O z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Ni x Ga y O z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); Ni x Al y O z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); (Ni x Mg 1-x ) y Ga 2(1-y) O 3-2y (In the formula, 0 <x<1および0<y<1である);(Mg x Ni 1-x ) z (Al y Ga 1-y ) 2(1-z )O 3-2z (wherein 0≦x≦1, 0≦y≦1, and 0≦z≦1); (Ni z Mg x Zn 1-x-z )(Al y Ga 1-y )2O4 (wherein 0≦(x, y, z)≦1); or (Zn p Mg x Ni 1-x-p ) z (Al y Ga 1-y ) 2(1-z) O 3-2z (In the formula, 0≦(p,x,y,z)≦1,

[0208] In some cases, the binary oxide precursors and sources described herein (e.g., those shown in Figures 6A, 8A-8B, 17, 18A-18C, 19-21, 26A-26C, 28A-28C, 30, or 40) can be used in combination with an activated oxygen source (e.g., those shown in Figures 8A-8B and 40), optionally in combination with an additional metal-containing source (e.g., those shown in Figure 40) to deposit an epitaxial layer: (In x B1-x ) 2y O 3z (wherein 0≦x≦1, 0.8≦y≦1.2, and 0.8≦z≦1.2); x B 1-x )2O3 (wherein 0≦x≦1); (In x Al 1-x ) 2y O 3z (wherein 0≦x≦1, 0.8≦y≦1.2, and 0.8≦z≦1.2); x Al 1-x )2O3 (wherein 0≦x≦1); (In x Ga 1-x ) 2y O 3z (wherein 0≦x≦1, 0.8≦y≦1.2, and 0.8≦z≦1.2); x Ga 1-x )2O3 (wherein 0≦x≦1); (In a Ga b Al c B d )2O3 (wherein 0≦(a, b, c, d)≦1, a+b+c+d=1); Ni x In 2(1-x) O 3-2x (wherein 0≦x≦1); Mg x In 2(1-x) O 3-2x (wherein 0≦x≦1); (Ni a Mg b Zn c ) x In2 (1-x) O 3-2x (wherein 0≦x≦1, 0≦(a,b,c)≦1, and a+b+c=1); (Ni a Mg b Zn c ) x (Ga d Al e B f In g ) 2(1-x) O 3-2x(where 0≦x≦1, 0≦(a,b,c,d,e,f,g)≦1, a+b+c=1, and d+e+f+g=1.) For example, the deposition system may include a binary oxide source for providing Ga, Al, B, and / or In, an active oxygen source, and one or more additional sources for providing Ni, Mg, and / or Zn to grow epitaxially (Ni a Mg b Zn c ) x (Ga d Al e B f In g ) 2(1-x) O 3-2x (where 0≦x≦1, 0≦(a,b,c,d,e,f,g)≦1, a+b+c=1, and d+e+f+g=1).

[0209] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source and optionally additional metal-containing sources to deposit the following epitaxial layers: Li 2x Ga 2(1-x) O 3-2x (wherein 0≦x≦1); Li(Al x Ga 1-x )O2 (wherein 0≦x≦1); (Al x Ga 1-x )2LiO2 (where 0≦x≦1); Li x Ni y O z where 0≦x≦1, 0≦y≦1, and 0≦z≦1; LiAlO2 and LiGaO2; Li2NiO3; Li2NiO2. For example, the deposition system may include a binary oxide source to provide Li, and a binary oxide source to provide Ga and / or Al, and an active oxygen source to produce Li(Al x Ga 1-x )O2 (where 0≦x≦1) can be grown epitaxially.

[0210] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source to deposit the following epitaxial layers: Ge x Ga 2(1-x) O 3-x (wherein 0≦x≦1); Ge x Al 2(1-x) O 3-x (wherein 0≦x≦1); Si x Ga 2(1-x) O 3-x (wherein 0≦x≦1); Si x Al 2(1-x) O 3-x (wherein 0≦x≦1); (Mg x Zn 1-x-y Ni y )2GeO4 (wherein 0≦x≦1, 0≦y≦1); or (Al x Ga 1-x )2(Si z Ge 1-z )O5, where 0≦x≦1 and 0≦z≦1. For example, the deposition system may include a binary oxide source for providing Ga and / or Al, and a binary oxide source for providing Ga and / or Al, and an active oxygen source, to produce (Al x Ga 1-x )2(Si z Ge 1-z )O5, where 0≦x≦1 and 0≦z≦1, can be epitaxially deposited. Si may be incorporated into Group III oxide materials at low concentrations (e.g., x<0.1) and may in some cases function as a dopant. For example, Si may be incorporated into Group III oxide materials such as (In a Ga b Al c B d )2O3 (where 0≦(a,b,c,d)≦1, a+b+c+d=1) in low concentrations (e.g., less than 10 mol % or less than 1 mol % of the total material). In some cases, one or more binary oxide sources can be used in combination with additional metal-containing sources to form the above materials.

[0211] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source to deposit epitaxial layers comprising one or more of Ga, Ge, Al, Si, B, Li, and In and oxygen. For example, epitaxial layers can be deposited containing (In a Ga b Al c B d )2O3, where 0≦(a,b,c,d)≦1, and a+b+c+d=1, with or without a lithium dopant, and with or without a Si dopant.

[0212] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source to deposit epitaxial layers comprising one or more of Ga, Al, B, and In, one or more of Ge and Si, and oxygen. For example, epitaxial layers can be deposited comprising (Al x Ga1- x )2(Si z Ge 1-z )O5, where 0≦x≦1 and 0≦z≦1, where Al and / or Ga, Si and / or Ge are provided to the growing epitaxial layer using two or more binary oxide precursor sources.

[0213] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source to deposit epitaxial layers comprising one or more of Ga, Al, B, and In; and oxygen. For example, epitaxial layers can be deposited containing Li(Al x Ga 1-x )O2 (wherein 0≦x≦1); or (Al x Ga 1-x )2LiO2, where 0≦x≦1, where Al and / or Ga, and Li are provided to the grown epitaxial layer using two or more binary oxide precursor sources.

[0214] In some cases, the binary oxide precursors and sources described herein can be combined with an active oxygen source and additional metal-containing sources to deposit epitaxial layers, including one or more of Ga, Al, B, and In (one or more binary oxide precursors); one or more of Zn, Ni, and Mg, and oxygen. For example, epitaxial layers can be deposited using (Ni z Mg x Zn 1-x-z )(Al y Ga 1-y )2O4 (wherein 0≦(x, y, z)≦1); or (Zn p Mg x Ni 1-x-p ) z (Al y Ga 1-y ) 2(1-z)O3-2z where 0≦(p,x,y,z)≦1, where Al and / or Ga are provided to the growing epitaxial layer using one or more binary oxide precursor sources, and Zn, Mg, and / or Ni are provided to the growing epitaxial layer using one or more additional metal-containing sources.

[0215] In some cases, epitaxial layers can be deposited using the binary oxide precursors and sources described herein in combination with an active oxygen source and additional metal-containing sources, including one or more of Si and Ge (one or more binary oxide precursors); one or more of Zn, Ni, and Mg, and oxygen. For example, epitaxial layers can be deposited using (Mg x Zn 1-x-y Ni y )2GeO4, where 0≦x≦1, 0≦y≦1, wherein Ge is provided to the growing epitaxial layer using a binary oxide precursor source and Zn, Mg, and / or Ni are provided to the growing epitaxial layer using one or more additional metal-containing sources.

[0216] In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source and optionally an additional metal-containing source to deposit epitaxial layers of materials containing Al, Ga, Ge, or Li shown in FIG. 28 of U.S. Patent No. 11,342,484 (incorporated herein by reference in its entirety). In some cases, the binary oxide precursors and sources described herein can be used in combination with an active oxygen source and optionally an additional metal-containing source to deposit epitaxial layers of materials containing Al, Ga, Ge, or Li shown in FIGS. 76A-1, 76A-2, 76B, and 87-89A of U.S. Patent No. 12,087,880 (incorporated herein by reference in its entirety).

[0217] Growth of ternary oxides from binary oxide precursor sources (Al x Ga 1-x )2O3, (In x Ga 1-x )2O3 and (Al x In 1-x )2O3 (where 0 ≤ x ≤ 1 or 0 < x < 1), the growth thermodynamics of ternary oxide semiconductors can be modeled. The modeling of the growth of β-Ga2O3 using Ga metal and O-based growth is conventionally known (e.g., as described in Togashi et al. (2023)). Hereinafter, methods and examples for growing films using a vapor (vapor) binary oxide source which is a suboxide of Group III (Ga2O, Al2O, In2O) and atomic oxygen (O) as an oxidizing agent are shown. The following methods can be implemented using a system capable of ultra-high vacuum (UHV) such as an MBE system, as well as a system using molecular organic precursors such as MOCVD and ALD.

[0218] In some cases, the method involves forming a crystalline sesquioxide (i.e., an oxide in which oxygen is present in a ratio of three atoms to two of one or more other elements, e.g., Ga2O3) film on a substrate using a series of gas-phase reactions between volatile suboxides and atomic oxygen. The basic reaction for each Group III element (e.g., M=Ga, Al, In) can be written as follows: M2O(g)+2O(g)→M2O3(s). Equation 12 These reactions are treated as equilibrium states with temperature-dependent equilibrium constants and are modeled in the following form: log 10 K(T)=a+b / T+clog 10 (T) Equation 13 where K is the equilibrium constant and a, b, and c are species-specific fitting parameters derived from the Gibbs free energy difference between reactants and products.

[0219] When forming ternary oxides, two different suboxide sources (MO and MO) are introduced simultaneously. The relevant linked reactions are as follows: Ga2O(g) + 2O(g) → Ga2O3(s) Equation 14 Al2O(g)+2O(g)→Al2O3(s) Equation 15 In2O(g)+2O(g)→In2O3(s) Equation 16 For a three-component system, (Al x Ga 1-x )2O3: Formula 14 + Formula 15 Formula 17 (In x Ga 1-x )2O3: Formula 14 + Formula 16 Formula 18 (Al x In 1-x )2O3: Formula 15 + Formula 16. Formula 19 The ternary composition x is determined, at least in part, by the ratio of the suboxide beam equivalent pressures (BEPs) or molar fluxes. x=φM2O / (φM2O+φM'2O). Equation 20

[0220] As part of the method for simulating ternary growth conditions, the following blocks can be implemented: 1. Determine the molar fluxes φGaO, φAlO, and φInO from the evaporation cell temperature and source vapor pressure. 2. The atomic oxygen flux (φO) is specified based on the plasma power, the activated oxygen source, and the system geometry. 3. For a given growth temperature T, the log 10 Calculate K(T). 4. Solve the coupled equilibrium equation: log 10 (KGa)=log 10 (pGa2O3 / (pGa2O pO 2 )) Equation 21 log 10 (KAl)=log 10 (pAl2O3 / (pAl2O pO 2 )) Equation 22 log 10 (KIn)=log 10 (pIn2O2 / (pIn2O pO 2 )) Equation 23 5. Determine the proportion of each solid phase oxide formed and calculate x for the ternary oxide.

[0221] In the above equations 21 to 23, "KGa" is the equilibrium constant of the reaction in equation 14, "KAl" is the equilibrium constant of the reaction in equation 15, and "KIn" is the equilibrium constant of the reaction in equation 16. Furthermore, "pGa2O3", "pGa2O", and "pO" are the partial pressures of Ga2O3, Ga2O, and O, respectively, "pAl2O3" and "pAl2O" are the partial pressures of Al2O3 and Al2O, respectively, and "pIn2O3" and "pIn2O" are the partial pressures of In2O3 and In2O, respectively.

[0222] In addition to atomic oxygen, other oxidants such as carbon monoxide (CO), nitrous oxide (NO), and nitric oxide (NO) can also be used when growing ternary oxide films. These oxidants introduce additional complexity into thermodynamic modeling but offer opportunities for functional doping. For example, CO and NO can oxidize MO(g) to MO(s), incorporating C or N atoms into the film. In another example, NO acts simultaneously as a strong oxidant and nitrogen source.

[0223] When these oxidizing agents are used, the following general reaction scheme applies: M2O(g)+2N2O(g)→M2O3(s)+2N2(g) Equation 24 M2O(g)+2NO(g)→M2O3(s)+N2(g) Equation 25 M2O(g)+2CO(g)→M2O3(s)+2C(s) Equation 26 M2O(g)+CO2(g)→M2O3(s)+C(s) Equation 27

[0224] Incorporation of nitrogen and carbon during growth provides an effective strategy for introducing deep acceptors, which compensate for oxygen vacancies (which would otherwise contribute to n-type conductivity), thereby enabling the realization of semi-insulating films.

[0225] This methodology provides a thermodynamic framework for modeling the equilibrium growth of ternary oxide systems using suboxide sources in an MBE environment. It can be extended to quartic systems and calibrated using K(T) values ​​derived from NIST JANAF or NASA thermochemical data. The use of alternative oxidizers, such as CO, NO, and NO, opens additional routes for doping control, enabling the synthesis of semi-insulating or compensated ternary (Al, Ga, In)O materials.

[0226] Terms Clause 1. A method for producing a binary oxide vapor precursor, the method comprising: enclosing elemental components in an open-ended vessel having a closed end and a vessel wall extending from the closed end to an open end; introducing solid binary oxide members into the open-ended vessel to form an encapsulated aggregate structure of the solid binary oxide members within the vessel wall, wherein at least a portion of the solid binary oxide members is between the elemental components and the open end of the open-ended vessel; and heating the elemental components to form elemental vapors that travel toward the open end of the open-ended vessel, wherein as the elemental vapor travels toward the open end, it reacts with the encapsulated aggregate structure of the solid binary oxide members to produce a binary oxide vapor precursor.

[0227] Clause 2. The method of clause 1, wherein the elemental components correspond to non-oxide components of the binary oxide vapor precursor, and each of the solid binary oxide members corresponds to a solid binary oxide stoichiometric form of the binary oxide vapor precursor.

[0228] Clause 3. The method of clause 1 or 2, further comprising: discharging the binary oxide vapor precursor from an open end of the open-ended vessel; and depositing a solid oxide material on a heated substrate by reacting the binary oxide vapor precursor with molecular oxygen to form a solid oxide material on the heated substrate.

[0229] Clause 4. The method of any one of clauses 1-3, further comprising selecting an amount of the solid binary oxide member introduced into the open-ended vessel such that the solid binary oxide member meets a minimum amount required to completely react with the elemental components to produce the binary oxide vapor precursor.

[0230] Clause 5. The method of any one of clauses 1-4, wherein the contained agglomerated structures are closely packed columns of the solid binary oxide members extending along a portion of the open-ended vessel.

[0231] Clause 6. The method of any one of clauses 1 to 5, wherein the solid binary oxide material is granules having a predetermined size distribution.

[0232] Clause 7. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is Ga2O(vapor), the elemental component is Ga, and the solid binary oxide component is Ga2O3.

[0233] Clause 8. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is GeO(vapor), the elemental component is Ge, and the solid binary oxide material is GeO2.

[0234] Clause 9. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is Al2O(vapor), the elemental component is Al, and the solid binary oxide member is Al2O3.

[0235] Clause 10. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is SiO(vapor), the elemental component is Si, and the solid binary oxide component is SiO2.

[0236] Clause 11. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is B2O(vapor), the elemental component is B, and the solid binary oxide component is B2O3.

[0237] Clause 12. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is In2O(vapor), the elemental component is In, and the solid binary oxide component is In2O3.

[0238] Clause 13. The method of any one of clauses 1-6, wherein the binary oxide vapor precursor is sLirO(vapor), the elemental component is Li, and the solid binary oxide component is Li2.

[0239] Clause 14. A binary oxide vapor source, the vapor source comprising: a container having a closed end and an open end; a first region located adjacent the closed end containing or configured to contain an elemental component; a first heater zone configured to heat the first region to produce elemental vapor from the elemental component; a second region located between the first region and the open end, the second region containing or configured to contain a solid binary oxide member; and a space adjacent the solid binary oxide member through which the elemental vapor can pass, wherein a product of the reaction between the elemental vapor and the solid binary oxide member is a binary oxide vapor precursor, the solid binary oxide member and the space are configured such that the binary oxide vapor precursor formed in the space can exit the binary oxide vapor source through the open end.

[0240] Clause 15. The binary oxide vapor source of clause 14, wherein the second region comprises an aggregate structure of the solid binary oxide member.

[0241] Clause 16. The binary oxide vapor source of clause 15, wherein the second region of the binary oxide vapor source comprises or is configured to comprise solid binary oxide members comprising a plurality of members (e.g., particles, granules, spheres, rods, etc.) having a size distribution such as that described by a Weibull distribution with a small b parameter, or a bimodal or multimodal size distribution (i.e., a mixture of small and large particles to improve packing density).

[0242] Clause 17. The binary oxide vapor source of any one of clauses 14-16, further comprising a second heater zone configured to heat the second region.

[0243] Clause 18. The binary oxide vapor source of any one of clauses 14 to 17, further comprising a third heater zone configured to heat a third region between the second region and the open end.

[0244] Clause 19. The binary oxide vapor source of any one of clauses 14 to 18, wherein the solid binary oxide member (or a cohesive structure formed from the solid binary oxide member) has a lower density than the elemental components at an operating temperature of the binary oxide vapor source.

[0245] Clause 20. The binary oxide vapor source of any one of clauses 14 to 19, wherein the solid binary oxide member (or a cohesive structure formed from the solid binary oxide member) has a lower density than the elemental components at an operating temperature of the binary oxide vapor source, and the first region further comprises the solid binary oxide member.

[0246] Clause 21. The binary oxide vapor source of any one of clauses 14 to 20, further comprising a first opening disposed at the open end, wherein the first opening comprises any aspect ratio and is configured to provide an exhaust distribution profile, an outlet operating pressure, and / or an outlet operating pressure differential at the first opening.

[0247] Clause 22. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is Ga2O(vapor), the elemental component is Ga, and the solid binary oxide member is Ga2O3.

[0248] Clause 23. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is GeO(vapor), the elemental component is Ge, and the solid binary oxide material is GeO2.

[0249] Clause 24. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is Al2O(vapor), the elemental component is Al, and the solid binary oxide member is Al2O3.

[0250] Clause 25. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is SiO(vapor), the elemental component is Si, and the solid binary oxide member is SiO2.

[0251] Clause 26. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is B2O(vapor), the elemental component is B, and the solid binary oxide material is B2O3.

[0252] Clause 27. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is In2O(vapor), the elemental component is In, and the solid binary oxide member is In2O3.

[0253] Clause 28. The binary oxide vapor source of any one of clauses 14 to 21, wherein the binary oxide vapor precursor is sLirO(vapor), the elemental component is Li, and the solid binary oxide component is Li2O.

[0254] Clause 29. A method for producing a binary oxide vapor precursor for a deposition process, the method comprising: providing a binary oxide vapor source comprising a closed end and an open end, a first region located adjacent the closed end containing elemental components, and a second region located between the first region and the open end, the second region containing an enclosed aggregate structure including solid binary oxide members and a space through which vapor can pass; heating the binary oxide vapor source to form elemental vapor from the elemental components; and reacting the elemental vapor with the solid binary oxide members as the elemental vapor passes through the space in the second region to produce a binary oxide vapor precursor that exits the binary oxide vapor source through the open end.

[0255] Clause 30. The method of clause 29, wherein the elemental components correspond to non-oxide components of the binary oxide vapor precursor, and each of the solid binary oxide members corresponds to a solid binary oxide stoichiometric form of the binary oxide vapor precursor.

[0256] Clause 31. The method of clause 29 or 30, further comprising depositing a solid oxide material on a heated substrate by reacting the binary oxide vapor precursor with molecular oxygen to form the solid oxide material on the heated substrate.

[0257] Clause 32. The method of any one of clauses 29-31, wherein the amount of the solid binary oxide component in the binary oxide vapor source satisfies the minimum amount required for the component to completely react with the elemental components to produce the binary oxide vapor precursor.

[0258] Clause 33. The method of any one of clauses 29-32, wherein the second region further comprises a closely packed column of the solid binary oxide members extending along a portion of the binary oxide vapor source.

[0259] Clause 34. The method of any one of clauses 29 to 33, wherein the solid binary oxide material is granules having a predetermined size distribution.

[0260] Clause 35. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is Ga2O(vapor), the elemental component is Ga, and the solid binary oxide component is Ga2O3.

[0261] Clause 36. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is GeO(vapor), the elemental component is Ge, and the solid binary oxide material is GeO2.

[0262] Clause 37. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is Al2O(vapor), the elemental component is Al, and the solid binary oxide member is Al2O3.

[0263] Clause 38. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is SiO(vapor), the elemental component is Si, and the solid binary oxide component is SiO2.

[0264] Clause 39. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is B2O(vapor), the elemental component is B, and the solid binary oxide component is B2O3.

[0265] Clause 40. The method of any one of clauses 29 to 34, wherein the binary oxide vapor precursor is In2O(vapor), the elemental component is In, and the solid binary oxide component is In2O3.

[0266] Clause 41. The binary oxide vapor precursor is sLi r 35. The method of any one of clauses 29 to 34, wherein the elemental component is O (vapour), the elemental component is Li, and the solid binary oxide member is Li2O3.

[0267] Clause 42. A material deposition system comprising a binary oxide vapor source and a growth chamber, the binary oxide vapor source comprising a closed end and an open end, a first region located adjacent the closed end containing or configured to contain an elemental component, a first heater zone configured to heat the first region to produce an elemental vapor from the elemental component, and a second region located between the first region and the open end, the second region containing or configured to contain a solid binary oxide member, wherein a product of a reaction between the elemental vapor and the solid binary oxide member is a binary oxide vapor precursor, the growth chamber being coupled to the open end of the binary oxide vapor source, wherein the binary oxide vapor precursor exits the open end of the binary oxide vapor source and enters the growth chamber.

[0268] Clause 43. The material deposition system of clause 42, wherein the growth chamber contains a partial pressure of molecular oxygen or an activated oxygen species capable of reacting with the binary oxide vapor precursor, the partial pressure being below an amount such that a significant amount of oxide condensate forms at the open end of the binary oxide vapor source at a predetermined reference temperature of the binary oxide vapor source.

[0269] Clause 44. The material deposition system of clause 42 or 43, wherein the system further comprises a condensation reduction arrangement including an inlet to the binary oxide vapor source, the inlet configured to introduce an inert carrier gas into the binary oxide vapor source and form a curtain or region of the inert carrier gas at the open end of the binary oxide vapor source, thereby displacing oxygen species that may react with the binary oxide vapor precursor at the open end of the binary oxide vapor source to form an oxide condensate.

[0270] Clause 45. The partial pressure of oxygen species is 10 -5 Torr or less than 10 -4 45. The material deposition system of any one of clauses 42-44, wherein the pressure is less than Torr.

[0271] Clause 46. A material deposition system according to any one of clauses 42 to 45, further comprising a heater configured to radiatively heat a substrate, the substrate being disposed within the growth chamber.

[0272] Clause 47. The material deposition system of any one of clauses 42-46, further comprising a pump coupled to the growth chamber.

[0273] Clause 48. A material deposition system according to any one of clauses 42 to 47, wherein the growth chamber is configured as a vacuum chamber and the open end of the binary oxide vapor source is within or at the boundary of the growth chamber.

[0274] Clause 49. A material deposition system according to any one of clauses 42 to 47, wherein the growth chamber is configured as a vacuum chamber and the binary oxide vapor source is configured as a remote source coupled to the growth chamber via a conduit.

[0275] Clause 50. A material deposition system according to any one of clauses 42 to 47, wherein the growth chamber is configured as a tube, the material deposition system further comprises a radiant heater disposed outside the tube, and the binary oxide vapor source is configured as a remote source coupled to the growth chamber via a conduit.

[0276] Clause 51. The material deposition system of clause 49 or 50, wherein the growth chamber is configured as a tube, the material deposition system further comprising a radiant heater disposed outside the tube, and the binary oxide vapor source is configured as a remote source coupled to the growth chamber via a conduit.

[0277] Clause 52. The material deposition system of clause 50, wherein the system further comprises a mixer configured such that a carrier gas and the binary oxide vapor precursor are introduced into the mixer and a mixture of the carrier gas and the binary oxide vapor precursor is transported from the binary oxide vapor source to the growth chamber through the conduit.

[0278] Clause 53. The material deposition system of any of clauses 42-52, further comprising a second binary oxide vapor source coupled to the growth chamber.

[0279] Clause 54. A material deposition system according to any one of clauses 42 to 53, further comprising an elemental or molecular source coupled to said growth chamber.

[0280] In some cases, a single embodiment may combine multiple features for brevity and / or to aid in understanding the scope of the present disclosure. In such cases, it should be understood that these multiple features may be provided separately (in separate embodiments) or in any other suitable combination. Alternatively, if separate features are described in separate embodiments, unless otherwise stated or implied, these separate features may be combined into a single embodiment. This also applies to claims that can be recombined in any combination. That is, a claim can be amended to include features defined in any other claim. Furthermore, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single elements. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc.

[0281] Reference has been made in detail to embodiments of the disclosed invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided for the purpose of explaining the technology, not limiting it. Indeed, while the specification has described in detail certain embodiments of the invention, it will be understood that those skilled in the art, upon gaining an understanding of the foregoing, will readily conceive of modifications, variations, and equivalents to these embodiments. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield yet a still further embodiment. It is therefore intended that the present subject matter encompass all such modifications and variations within the scope of the appended claims and their equivalents. These and other modifications and variations to the present invention can be practiced by those skilled in the art without departing from the scope of the invention, which is more particularly set forth in the appended claims. Moreover, those skilled in the art will recognize that the foregoing description is by way of example only and is not intended to limit the invention.

Claims

1. 1. A method for producing a binary oxide vapor precursor for a deposition process, comprising:

1. A binary oxide vapor source, comprising: a closed end and an open end; a first region located adjacent the closed end that includes an elemental component; a second region located between the first region and the open end, the second region including an enclosed aggregate structure having solid binary oxide members and spaces through which vapor can pass; heating the binary oxide vapor source to form elemental vapors from the elemental components; reacting the elemental vapor with the solid binary oxide member as the elemental vapor passes through the space in the second region to produce a binary oxide vapor precursor that exits the binary oxide vapor source through the open end.

2. 2. The method of claim 1, wherein the elemental components correspond to non-oxide components of the binary oxide vapor precursor, and each of the solid binary oxide members corresponds to a solid binary oxide stoichiometric form of the binary oxide vapor precursor.

3. 3. The method of claim 1 or 2, further comprising depositing a solid oxide material on a heated substrate by reacting the binary oxide vapor precursor with molecular oxygen to form the solid oxide material on the heated substrate.

4. 4. The method of claim 1, wherein the amount of the solid binary oxide member in the binary oxide vapor source satisfies a minimum amount required for the solid binary oxide member to completely react with the elemental components to produce the binary oxide vapor precursor.

5. 5. The method of claim 1, wherein the second region further comprises a closely packed column of the solid binary oxide members extending along a portion of the binary oxide vapor source.

6. The method of any one of claims 1 to 5, wherein the solid binary oxide member is a granule having a predetermined size distribution.

7. The binary oxide vapor precursor is Ga ２ O (vapor), the elemental component is Ga, and the solid binary oxide member is Ga ２ O ３ The method according to any one of claims 1 to 6, wherein

8. the binary oxide vapor precursor is GeO (vapor), the elemental component is Ge, and the solid binary oxide material is GeO ２ The method according to any one of claims 1 to 6, wherein

9. The binary oxide vapor precursor is Al ２ O (vapor), the elemental component is Al, and the solid binary oxide member is Al ２ O ３ The method according to any one of claims 1 to 6, wherein

10. the binary oxide vapor precursor is SiO(vapor), the elemental component is Si, and the solid binary oxide member is SiO ２ The method according to any one of claims 1 to 6, wherein

11. The binary oxide vapor precursor is B ２ O (vapor), the elemental component is B, and the solid binary oxide member is B ２ O ３ The method according to any one of claims 1 to 6, wherein

12. The binary oxide vapor precursor is In ２ O (vapor), the elemental component is In, and the solid binary oxide member is In ２ O ３ The method according to any one of claims 1 to 6, wherein

13. The binary oxide vapor precursor is sLi ｒ O (vapor), the elemental component is Li, and the solid binary oxide member is Li ２ O ３ The method according to any one of claims 1 to 6, wherein

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