Vapor deposition process for forming magnesium indium zinc oxide (MIZO) layers

Abstract

Methods of forming a magnesium indium zinc oxide (MIZO) layer by vapor deposition are provided. In some embodiments, a cyclic deposition process for forming a MIZO layer includes a deposition cycle including alternately and sequentially contacting a substrate with a vapor-phase indium precursor, a vapor-phase zinc precursor, a vapor-phase magnesium precursor, and an oxygen reactant in a reaction chamber.

Description

Technical Field

[0001] The present disclosure relates generally to the field of semiconductor processing methods, and to the field of device and integrated circuit fabrication. More specifically, the present disclosure relates to a vapor deposition process for forming a magnesium indium zinc oxide (MIZO) layer. Background Art

[0002] Semiconductor oxides are increasingly used in the semiconductor industry. For example, semiconductor oxides can be used as active layers in thin film transistors (TFTs), access transistors in 3D NAND / 3D DRAM applications, and semiconductor layers in metal-semiconductor-metal (MSM) type photodetectors. However, the performance of devices and / or integrated circuits containing certain potential semiconductor oxide materials may be negatively affected by, for example, lack of stability of the materials, low carrier mobility, and high leakage current. Therefore, there is a need for improved semiconductor oxide materials and methods of forming such materials.

[0003] Any discussion set forth in this section, including discussion of problems and solutions, has been included in the present disclosure merely to provide context for the present disclosure. Such discussion should not be construed as an admission that any or all information was known or constituted prior art when the present invention was made. Summary of the invention

[0004] This Summary may introduce some concepts in a simplified form that are further described below. This Summary is not intended to necessarily identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0005] Various embodiments of the present disclosure relate to methods for forming a magnesium indium zinc oxide (MIZO) layer on a substrate surface. As described in more detail below, the method described herein can form a MIZO layer using a cyclic deposition process, particularly an atomic layer deposition process. For example, such a MIZO layer can be used as an n-type semiconductor oxide in front-end process (FEOL) applications and back-end process (BEOL) applications. In addition, compared with other potential semiconductor oxide materials, the MIZO layer deposited according to the embodiments of the present disclosure exhibits greater material stability. As a non-limiting example, the manufacture of semiconductor devices and integrated circuits is typically carried out in equipment, particularly in a reaction chamber, using a strictly controlled atmosphere. Such a controlled atmosphere typically uses a hydrogen environment (or an environment that at least includes a hydrogen component). In such an example, hydrogen can have a negative impact on the stability of some potential semiconductor oxide materials. However, the MIZO layer deposited according to the embodiments of the present disclosure maintains material stability in a hydrogen environment and is therefore very suitable for use in manufacturing devices and integrated circuits. Semiconductor oxide materials.

[0006] According to an example of the present disclosure, a method for forming a magnesium indium zinc oxide (MIZO) layer is provided. The exemplary method includes placing a substrate in a reaction chamber and performing a cyclic deposition process including a plurality of repeated deposition cycles. In such an example, the deposition cycle includes (a) contacting the substrate with a vapor-phase indium precursor, (b) contacting the substrate with a vapor-phase zinc precursor, (c) contacting the substrate with a vapor-phase magnesium precursor, and (d) contacting the substrate with an oxygen reactant.

[0007] According to an example of the present disclosure, the deposition cycle includes an indium oxide sub-cycle, a zinc oxide sub-cycle, and a magnesium oxide sub-cycle. In such an example, the oxygen reactant contacts the substrate after step (a), after step (b), and after step (c).

[0008] According to an example of the present disclosure, a unit deposition cycle includes an indium oxide sub-cycle and a magnesium zinc oxide sub-cycle. In such an example, the oxygen reactant contacts the substrate after step (a) and after steps (b) and (c) are completed. In such an example, the MIZO layer includes a mixture of indium oxide and magnesium zinc oxide.

[0009] In some embodiments, the MIZO layer has a magnesium content of less than 40 atomic %.

[0010] In some embodiments, the cyclic deposition process is performed at a deposition temperature below 250°C.

[0011] In some embodiments, the vapor phase indium precursor includes a ligand selected from the group consisting of alkyl, alkylamino, alkoxy, halide, cyclopentadienyl (Cp), alkoxide, amide, amidine, guanidinium, β-diketonate, and triazene. In such examples, the vapor phase indium precursor is selected from the group consisting of trimethyl indium, triethyl indium, ethyl dimethyl indium, InMe2(CH2CH2CH2NMe2), InEt2(CH2CH2CH2NMe2), InMe2(CH2CH2CH2NEt2), InEt2(CH2CH2CH2NEt2), InCl, InCl3, InMe2Cl, In(CpCH2CH2NMe2), In(CpCH2CH2CH2NMe2), InMe2(CpCH2CH2NMe2), InMe2(CpCH 2CH2CH2NMe2), In(CpCH2CH2OMe), In(CpCH2CH2CH2OMe), InMe2(CpCH2CH2OMe), InMe2(CpCH2CH2OMe, tri(tert-butoxy)indium(III), tri(tert-butoxy)indium(III), tri(isopropoxy)indium(III), In(dmap)3, In(dmamp)3, In(dmamb)3, InMe2(dmap), InMe2(dmamp), InMe2(dmamb), InEt 2(dmap)、InEt2(dmamp)、InEt2(dmamb)、In(dmamp)2(OiPr)、InMe2(NMe2)、InMe2(NEt2)、InMe2(NEtMe)、InEt2(NMe2)、I nEt2(NEt2), InEt2(NEtMe), InMe2[N(SiMe3)2], InEt2[N(SiMe3)2], In(sBu2AMD)3, In(tBu2AMD)3, In(iPr2AMD)3 or In(tP n2AMD)3, In(tBu2FMD)3, In(iPr2FMD)3, In(tPn2FMD)3, In(thd)3, In(acac)3, In(hfac)3, as well as tri(di-tert-butyltriazene)indium(III), In(sBu2FMD)3 and an indium precursor represented by InR2L, wherein R is a methyl or ethyl ligand, and wherein L is selected from tBu2AMD, iPr2AMD, tPn2AMD, sBu2AMD, tBu2FMD, iPr2FMD, tPn2FMD and sBu2FMD.

[0012] In some embodiments, the vapor phase zinc precursor includes a ligand selected from the group consisting of alkyl, alkylamino, alkoxy, halide, cyclopentadienyl (Cp), alkoxide, aminoalkoxide, amide, carboxylate, and ketimine. In such an example, the vapor phase zinc precursor is selected from the group consisting of dimethyl zinc, diethyl zinc, bis[3-(N,N-dimethylamino)propyl]zinc, bis[3(methoxy)propyl]zinc, bis[3-(ethoxy)propyl]zinc, ZnCl2, ZnBr2, ZnI2, Zn(thd)2, Zn(acac)2, Zn(hfac)2, Zn(dmap)2, Zn(dmamp)2, Zn(dmamb)2, Zn(dab)2, Zn(damb)2, Zn(damp)2, Zn(dadb)2, ZnMe(OiPr), bis(trimethylsilylamino)zinc, zinc acetate, bis(N-(3'-dimethylaminopropyl) )-2-penten-2-one-4-imino)zinc (II), bis(N-(3'-dimethylaminoethyl)-2-penten-2-one-4-imino)zinc (II), bis(N-(3'-ethoxypropyl)-2-penten-2-one-4-imino)zinc (II), bis(N-(2'-ethoxyethyl)-2-penten-2-one-4-imino)zinc (II), bis(N-(3'-methoxypropyl)-2-penten-2-one-4-imino)zinc (II), bis(N-(2'-methoxyethyl)-2-penten-2-one-4-imino)zinc (II) and bis(N-(n-propyl)-2-penten-2-one-4-imino)zinc (II).

[0013] In some embodiments, the gas phase magnesium precursor includes a ligand selected from cyclopentadienyl (Cp), β-diketonate, amidine, diazadiene (DAD). In such examples, the gas phase magnesium precursor is selected from: MgCp2, Mg(MeCp)2, Mg(EtCp)2, Mg(thd)2, Mg(acac)2, Mg(hfac)2, Mg(sBu2AMD)2, Mg(tBu2AMD)2, Mg(iPr2AMD)2, Mg(tPn2AMD)2, Mg(sBu2FMD)2, Mg(tBu2FMD)2, Mg(iPr2FMD)2, Mg(tPn2FMD)2, Mg(tBu2DAD)2, Mg(sBu2DAD)2, Mg(iPr2DAD)2, Mg(tPn2DAD)2.

[0014] In some embodiments, the gas-phase oxygen reactant includes one or more of water, ozone, and H2O2.

[0015] According to additional examples of the present disclosure, an atomic layer deposition (ALD) process for forming a magnesium indium zinc oxide (MIZO) layer is provided. In such an example, the ALD process includes a deposition cycle, which includes alternating and sequentially contacting a substrate with trimethyl indium, diethyl zinc, bis(cyclopentadienyl) magnesium (II), and oxygen reactants in a reaction chamber, and repeating the deposition cycle until a MIZO layer of desired thickness and composition is formed. In such an example, the MIZO layer has a magnesium content of less than 40 atomic %.

[0016] According to other examples of the present disclosure, an atomic layer deposition (ALD) method for forming a magnesium indium zinc oxide (MIZO) layer on a substrate in a reaction chamber is provided. In such an example, the method includes performing a deposition cycle, the deposition cycle including alternately and sequentially contacting the substrate with a vapor phase indium precursor, a vapor phase zinc precursor, a vapor phase magnesium precursor, an oxygen reactant, and a second reactant. In such an example, the method also includes repeating the deposition cycle two or more times. In such an example, the second reactant includes NH 3 、N 2 O、NO 2 and H 2 O 2 In such examples, the substrate is in contact with the oxygen reactant and the second reactant simultaneously. In such examples, the MIZO layer has a magnesium content of less than 40 atomic %.

[0017] In order to summarize the present invention and the advantages achieved relative to the prior art, certain objects and advantages of the present invention have been described above. Of course, it should be understood that not all of these objects or advantages may be achieved according to any particular embodiment of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be implemented or performed in a manner that achieves or optimizes one advantage or a group of advantages taught or suggested herein without having to achieve other objects or advantages taught or suggested herein.

[0018] All of these embodiments are within the scope of the invention disclosed herein. These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings, the invention not being limited to any particular embodiment disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the figure number in which the element is first introduced.

[0020] A more complete understanding of exemplary embodiments of the present disclosure may be obtained by referring to the detailed description and claims when considered in conjunction with the following illustrative drawings.

[0021] Figure 1An exemplary cyclic deposition process according to an embodiment of the present disclosure is shown.

[0022] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0023] The description of exemplary embodiments of methods and structures provided below is merely exemplary and is for illustrative purposes only. The following description is not intended to limit the scope of the present disclosure or the claims. In addition, the recitation of multiple embodiments having the indicated features or steps is not intended to exclude other embodiments having additional features or steps or other embodiments incorporating different combinations of the described features or steps.

[0024] As described in more detail below, various embodiments of the present disclosure provide methods for forming a magnesium indium zinc oxide (MIZO) layer. Exemplary methods can be used to form a MIZO layer on a substrate surface by a cyclic deposition process, especially an atomic layer deposition process. The cyclic deposition process of the present invention may include performing two or more deposition cycles, wherein each deposition cycle includes the following steps: (a) contacting the substrate with a gas phase indium precursor, (b) contacting the substrate with a gas phase zinc precursor, (c) contacting the substrate with a gas phase magnesium precursor, and (d) contacting the substrate with an oxygen reactant. The steps (ad) of the deposition cycle can be performed in any order, each step is repeated multiple times, and additional steps can be selected to be included in the deposition cycle. In addition, the deposition cycle may include a super cycle, wherein the super cycle includes one or more sub-cycles, each of which is used to form a component of the MIZO layer. Therefore, the cyclic deposition process of the present disclosure allows the controlled formation of a MIZO layer with desired material properties, such as, but not limited to, composition, thickness, stoichiometry, conductivity, dopant concentration, etc.

[0025] In the present disclosure, a gas may include a material that is a gas at normal temperature and pressure (NTP), a vaporized solid, and / or a vaporized liquid, and may consist of a single gas or a mixture of gases, depending on the context.

[0026] As used herein, the terms "precursor" and "reactant" may refer to molecules (compounds or molecules containing a single element) that participate in a chemical reaction that produces another compound. A precursor typically contains a moiety that is at least partially incorporated into the compound or element produced by the chemical reaction. The compound or element so obtained may be deposited on a substrate. A reactant may be an element or compound that is not incorporated to a large extent into the resulting compound or element. In some cases, the term reactant may be used interchangeably with the term precursor.

[0027] As used herein, the term "substrate" may refer to any one or more underlying materials that can be used to form or on which a device, circuit, or film can be formed. The substrate may include a bulk material, such as silicon (e.g., single crystal silicon), other Group IV materials, such as germanium, or other semiconductor materials, such as Group II-VI or Group III-V semiconductor materials, and may include one or more layers covering or located below the bulk material. In addition, the substrate may include various features, such as depressions, protrusions, etc. formed in or on at least a portion of the substrate layer. For example, the substrate may include a semiconductor material. The semiconductor material may include or be used to form one or more of the source, drain, or channel regions of the device. The substrate may also include an interlayer dielectric (e.g., silicon oxide) and / or a high dielectric constant material layer covering the semiconductor material. In this article, a high dielectric constant material or a high-k dielectric material is a material whose dielectric constant is greater than the dielectric constant of silicon dioxide.

[0028] As used herein, the terms "film" and / or "layer" can be used interchangeably and can refer to any continuous or discontinuous structure and material, such as materials deposited by the methods disclosed herein. For example, the film and / or layer can include a two-dimensional material, a three-dimensional material, nanoparticles, a partial or complete molecular layer or a partial or complete atomic layer or atom and / or molecular clusters. The film or layer can be composed in part or in whole of a plurality of dispersed atoms on a substrate surface and / or embedded in a substrate and / or embedded in a device manufactured on the substrate. The film or layer can include a material or layer having pinholes and / or islands. The film or layer can be at least partially continuous. The film or layer can be patterned, for example, subdivided, and can be composed of a plurality of semiconductor devices.

[0029] As used herein, the term "cyclic deposition process" or "cyclic deposition process" may refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber to deposit layers on a substrate, and includes process techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes including an ALD component and a cyclic CVD component. In some cases, a cyclic deposition process may include continuous flow of one or more precursors, reactants, or inert gases, as well as pulsing other precursors or reactants.

[0030] As used herein, the term "atomic layer deposition" may refer to a vapor deposition process in which a deposition cycle (typically a plurality of consecutive deposition cycles) is performed in a processing chamber. The term atomic layer deposition used herein is also meant to include processes specified by related terms, such as chemical vapor atomic layer deposition, when performed with alternating pulses of precursor / reactive gas and purge gas (e.g., inert carrier gas). Typically, for an ALD process, during each cycle, a precursor is introduced into a reaction chamber and chemically adsorbed onto a deposition surface (e.g., a substrate surface that may include previously deposited materials or other materials from a previous ALD cycle), forming a monolayer or sub-monolayer of a material that is not easily reacted with an additional precursor (i.e., a self-limiting reaction). Thereafter, in some cases, a reactant (e.g., another precursor or reactive gas) may be subsequently introduced into the processing chamber for converting the chemically adsorbed precursor into a desired material on the deposition surface. The reactant is capable of further reacting with the precursor. During one or more cycles, such as during each step of each cycle, a purge step may be utilized to remove any excess precursor from the processing chamber and / or remove any excess reactant and / or reaction byproducts from the reaction chamber.

[0031] As used herein, the term "purge" may refer to the process of providing an inert or substantially inert gas to a reaction chamber between two gas pulses, which gases may otherwise react with each other. For example, a purge may be provided between a precursor pulse and a reactant pulse, for example using an inert gas, such as a rare gas, to reduce gas phase interactions that may occur between the precursor and the reactant. It should be understood that the purge may be performed in time or space, or both. For example, in the case of a time purge, a purge step may be used, for example, in a time sequence of providing a precursor to the reaction chamber, providing a purge gas to the reaction chamber, and providing a reactant or another precursor to the reaction chamber, wherein the substrate on which the layer is deposited does not move. In the case of a space purge, the purge step may take the form of moving the substrate from a first position where a precursor is (e.g., continuously) supplied to a second position where a reactant or other precursor is (e.g., continuously) supplied through a purge gas curtain.

[0032] In addition, in the present disclosure, any two numbers of a variable may constitute a feasible range for the variable, and any range indicated may include or exclude endpoints. In addition, any values ​​of the variables indicated (regardless of whether they are expressed with the term "about") may refer to exact values ​​or approximate values, and include equivalents, and may refer to average values, medians, representative values, multiple values, etc. In addition, in the present disclosure, the terms including, consisting of, and having independently refer to generally or broadly including, comprising, consisting of, or substantially consisting of in some embodiments.

[0033] In this disclosure, in some embodiments, any defined meaning does not necessarily exclude the ordinary and customary meaning.

[0034] According to an example of the present disclosure, a method of forming a magnesium indium zinc oxide (MIZO) layer by a vapor deposition process (e.g., atomic layer deposition) is provided. In some embodiments, the MIZO layer can be formed on a substrate by a vapor deposition process, the vapor deposition process comprising alternately and sequentially exposing the substrate to a vapor indium precursor, a vapor zinc precursor, a vapor magnesium precursor, and one or more oxygen reactants.

[0035] As described below, in some embodiments, the cyclic deposition process of the present disclosure includes a deposition cycle that includes one or more sub-cycles of depositing oxides. For example, in some embodiments, the binary oxide of each individual precursor can be deposited in three deposition sub-cycles. In some embodiments, the deposition cycle (i.e., super cycle) includes a first sub-cycle of depositing indium oxide from a vapor phase indium precursor, a second sub-cycle of depositing zinc oxide from a vapor phase zinc precursor, and a third sub-cycle of depositing magnesium oxide from a vapor phase magnesium precursor. In some embodiments, in the sub-cycles, the substrate is alternately and sequentially exposed to indium, zinc or magnesium vapor phase precursors and oxygen reactants.

[0036] In other embodiments, two or more precursors are provided before the oxygen reactant in a sub-cycle. For example, in some embodiments, indium zinc oxide (IZO) is deposited in one sub-cycle by alternating and sequentially exposing the substrate to an indium precursor, a zinc precursor, and an oxygen reactant, while magnesium zinc oxide (MZO) is deposited in a second sub-cycle by alternating and sequentially exposing the substrate to a zinc precursor, a magnesium precursor, and an oxygen reactant.

[0037] In other embodiments, two or more precursors are provided before the oxygen reactant in a sub-cycle to form a ternary oxide before or after the binary oxide is formed. For example, in some embodiments, indium oxide is deposited by alternately and sequentially exposing the substrate to an indium precursor and an oxygen reactant in one sub-cycle, and magnesium zinc oxide (MZO) is deposited by alternately and sequentially exposing the substrate to a zinc precursor, a magnesium precursor, and an oxygen reactant in a second sub-cycle.

[0038] In some embodiments, the deposition cycle includes exposing the substrate to each of a magnesium precursor, a zinc precursor, and an indium precursor, and exposing the substrate to an oxygen reactant after exposure to the three precursors, wherein the three precursors may be provided in any order.

[0039] In some embodiments, additional reactant gases, such as NH 3 、N 2 O、NO 2 and / or H 2 O 2 of gas to improve layer properties.

[0040] In some embodiments, the MIZO layer may include a mixture of one or more individual oxides, such as indium zinc oxide (IZO) and magnesium zinc oxide (MZO).

[0041] In some embodiments, the MIZO layer may include one or more binary oxides such as indium oxide, zinc oxide, and magnesium oxide, and a mixture of one or more ternary oxides such as indium zinc oxide (IZO) and magnesium zinc oxide (MZO). Various oxides can be used to adjust the MIZO layer to obtain the desired results. For example, the amount of each of indium, magnesium, and zinc in the layer can be adjusted.

[0042] In some embodiments, post-deposition annealing and / or post-deposition treatment may be performed, for example, to improve the electrical properties of the layer. Post-deposition annealing may include, for example, annealing in an oxygen environment. The disclosed method enables high conformality and full stoichiometric control of the MIZO layer, for example on high aspect ratio 3D structures, as required for some memory applications.

[0043] In some embodiments, a magnesium indium zinc oxide (MIZO) layer deposited by the disclosed method can be used as a channel material in a transistor. This can allow extremely low cutoff current and higher carrier mobility compared to silicon. In some embodiments, the MIZO layer is deposited at low temperature (<250°C), allowing it to be used in back-end-of-line (BEOL) devices. In some embodiments, the MIZO layer of the present disclosure is used as a channel region in a BEOL logic device. In some embodiments, the MIZO layer of the present disclosure can be deposited on a three-dimensional structure with high conformality and high uniformity. This can allow the MIZO layer to be used in high aspect ratio devices such as DRAM. In some embodiments, the MIZO layer of the present disclosure is used as a DRAM access transistor channel. In some embodiments, the MIZO layer of the present disclosure is used as a VNAND (vertical NAND) channel.

[0044] Other situations where the MIZO layer may be utilized will be apparent to the skilled person.In some embodiments, the MIZO layer is not used as a transparent layer transistor (TFT) used in a display.

[0045] As described above, a vapor deposition process is provided to deposit the MIZO layer. In some embodiments, a cyclic deposition process, in particular an atomic layer deposition (ALD) technique, is used to deposit a conformal MIZO layer. In vapor deposition techniques, ALD has the advantage of providing high conformality at low temperatures. In some embodiments, a cyclic CVD process can be utilized. Therefore, in some embodiments, the reaction temperature can be higher than the decomposition temperature of at least one precursor. In a cyclic CVD reaction, at least partial mixing of one or more precursors and reactants may occur. For example, the ALD process described below can be modified to provide precursors and reactants simultaneously or in at least partially overlapping pulses in each sub-cycle.

[0046] ALD type processes are based on controlled surface reactions of precursor chemicals. The surface reactions may or may not be self-limiting. Gas phase reactions can be avoided by feeding the precursors alternately and sequentially into the reaction chamber. The gas phase reactants are typically separated from one another in the reaction chamber, for example, by removing excess reactants and / or reactant byproducts from the reaction chamber between reactant pulses, a process which may be referred to as purging.

[0047] In short, the substrate is loaded and placed in the reaction chamber and is heated to a suitable substrate temperature (i.e., deposition temperature) usually under reduced pressure. The substrate can be, for example, a semiconductor substrate. The deposition temperature can be maintained below the precursor thermal decomposition temperature, but maintained at a sufficiently high level to avoid reactant condensation and provide activation energy for the desired surface reaction. Of course, for any given ALD reaction, the appropriate temperature window will depend on the surface termination and the types of reactants involved.

[0048] In some embodiments, the deposition temperature (i.e., substrate temperature) is from about 20° C. to about 600° C., from about 100° C. to about 400° C., or from about 150° C. to about 300° C., or from about 200° C. to about 250° C. In some embodiments, the deposition temperature is below about 600° C., or below about 500° C., or below about 400° C., or below about 300° C., or below about 250° C., or below about 225° C., or below about 200° C. In some embodiments, the deposition temperature is between 250° C. and 150° C.

[0049] Each of the indium precursor, zinc precursor, and magnesium precursor can be introduced into the chamber separately in the form of a gas phase pulse and contacted with the substrate surface. In some embodiments, the substrate surface includes a three-dimensional structure. In some embodiments, the conditions are selected so that no more than about one monolayer of each precursor is adsorbed on the substrate surface in a self-limiting manner.

[0050] One or more gaseous oxygen reactants are pulsed into the chamber where they react with the zinc, indium and / or magnesium species on the surface to form the corresponding oxides.

[0051] Excess precursors or reactants and reaction byproducts, if any, can be removed from the substrate and substrate surface and near the substrate and substrate surface between each pulse of precursor or reactant. In some embodiments, reactants and reaction byproducts, if any, can be removed by purging. Purging can be accomplished, for example, with pulses of an inert gas such as nitrogen or argon.

[0052] Purging the reaction chamber means removing gaseous precursors or reactants and / or gaseous byproducts from the reaction chamber, for example by evacuating the reaction chamber with a vacuum pump and / or by replacing the gas in the reactor with an inert gas such as argon or nitrogen. Typical purge times are from about 0.05 seconds to about 20 seconds, from about 1 second to about 10 seconds, or from about 1 second to about 2 seconds. However, other purge times may also be used, for example when depositing layers on extremely high aspect ratio structures or other structures with complex surface morphology. Technicians can easily determine suitable pulse times according to specific circumstances.

[0053] In other embodiments, excess precursor (or reactant and / or reaction byproduct, etc.) is removed from the substrate surface or region of the substrate by physically moving the substrate from a location containing the precursor, reactant, and / or reaction byproduct.

[0054] The steps of contacting the substrate with each precursor and reactant and removing excess precursor or reactant and reaction byproducts are repeated, such as by pulsing, until a MIZO layer of desired thickness is formed on the substrate, typically leaving no more than about one molecular monolayer per complete deposition cycle.

[0055] As described above, each pulse or stage of each deposition cycle can be self-limiting. Excess reactant precursors can be provided in each stage to saturate the susceptible structure surface. Surface saturation ensures that the reactants substantially occupy all or most of the available reaction sites (for example, limited by physical size or "steric hindrance"), thereby ensuring excellent step coverage. In some arrangements, the degree of self-limiting behavior can be adjusted by, for example, allowing some overlap of reactant pulses to balance deposition rate (by allowing some CVD-type reactions) with conformality. The ideal ALD conditions in which the reactants are fully separated in time and space provide nearly perfect self-limiting behavior, thereby providing maximum conformality, but steric hindrance results in less than one molecular layer per cycle. Limited CVD reactions mixed with self-limiting ALD reactions can increase deposition rates. As described above, in some embodiments, a pulsed CVD process is used.

[0056] In some embodiments, the reaction space can be in a single wafer ALD reactor or a batch ALD reactor, where deposition on multiple substrates occurs simultaneously. In some embodiments, the substrate (e.g., a semiconductor workpiece) on which it is desired to be deposited is loaded into the reaction space of the reaction chamber. The reaction chamber can be part of a combination tool in which various different processes in the formation of integrated circuits are performed. In some embodiments, a flow-type reactor is used. In some embodiments, a single wafer ALD reactor with high throughput manufacturing capabilities is used. In other embodiments, a batch reactor comprising multiple substrates is used. For embodiments using a batch ALD reactor, the number of substrates is in the range of 10 to 200, in the range of 50 to 150, or in the range of 100 to 130.

[0057] In addition to these ALD reactors, many other types of reactors capable of ALD layer growth can be used, including CVD reactors equipped with appropriate equipment and pulse precursor devices. In some embodiments, a flow-type ALD reactor is used. The reactants are typically kept separate until they reach the reaction chamber, minimizing common lines for precursors. However, other arrangements are also possible.

[0058] Suitable batch reactors include, but are not limited to, reactors specifically designed to enhance the ALD process. In some embodiments, a vertical batch reactor is used in which the boat rotates during processing. Thus, in some embodiments, the wafer is rotated during processing. In some embodiments using a batch reactor, the wafer-to-wafer uniformity is less than 3% (1sigma), less than 2%, less than 1%, or even less than 0.5%.

[0059] The MIZO deposition process described here can optionally be performed in a reaction chamber connected to a cluster tool. In a cluster tool, because each reaction chamber is dedicated to one type of process, the temperature of the reaction chambers in each module can be kept constant, which can increase throughput compared to reactors in which the substrate is heated to the processing temperature before each run.

[0060] Now turning to the attached figure, Figure 1 A cyclic deposition process 100 including a deposition cycle 104 is shown. Briefly, according to an example of the present disclosure, the cyclic deposition process 100 includes placing a substrate in a reaction chamber and heating the substrate to a suitable deposition temperature (step 102), followed by performing a plurality of repeated deposition cycles 104, wherein the deposition cycles include the following steps: (a) contacting the substrate with a vapor phase indium precursor (step 106), (b) contacting the substrate with a vapor phase zinc precursor (step 108), (c) contacting the substrate with a vapor phase magnesium precursor (step 110), and (d) contacting the substrate with an oxygen reactant (step 112). The deposition cycle 104 can be repeated (as shown by the cyclic loop 114) to deposit a layer of desired thickness and composition.

[0061] According to an example of the present disclosure, the deposition cycle 104 may include an indium oxide sub-cycle, a zinc oxide sub-cycle, and a magnesium oxide sub-cycle. In such an example, the oxygen reactant contacts the substrate after step (a) (step 106), step (b) (step 108), and step (c) (step 110).

[0062] According to an example of the present disclosure, deposition cycle 104 may include an indium oxide sub-cycle and a magnesium zinc oxide sub-cycle. In such an example, the oxygen reactant contacts the substrate after step (a) (106) and after steps (b) and (c) (steps 108 and 110) are completed. In such an example, the MIZO layer includes a mixture of indium oxide and magnesium zinc oxide (MZO).

[0063] In more detail, according to the examples of the present disclosure, in some embodiments, at least one of an indium precursor, a zinc precursor, and a magnesium precursor is provided before the oxygen reactant. In some embodiments, each of an indium precursor, a zinc precursor, and a magnesium precursor is provided before the oxygen reactant. The indium precursor, the zinc precursor, and the magnesium precursor can be provided in any order. In some embodiments, the precursors are provided sequentially in a deposition cycle, wherein the substrate is contacted alternately in the order of an indium precursor, a zinc precursor, a magnesium precursor, and an oxygen reactant. The deposition cycle is repeated to deposit a MIZO layer of a desired thickness. The deposition cycle can be written as [indium precursor + zinc precursor + magnesium precursor + oxygen reactant] x N1, where N1 is an integer and the square brackets represent a deposition cycle, such as an ALD deposition cycle.

[0064] In some embodiments, an oxygen reactant may be provided after one or more of an indium precursor, a zinc precursor, and a magnesium precursor. For example, in some embodiments, a MIZO deposition cycle includes a super cycle comprising three sub-cycles, each of which forms a respective oxide. In the first indium oxide sub-cycle, the substrate is contacted alternately and sequentially with an indium precursor and an oxygen reactant. The first sub-cycle may be repeated once, twice, or more times. In the second zinc oxide sub-cycle, the substrate is contacted alternately and sequentially with a zinc precursor and an oxygen reactant. The second sub-cycle may be repeated once, twice, or more times. In the third magnesium oxide sub-cycle, the substrate is contacted alternately and sequentially with a magnesium precursor and an oxygen reactant. The third sub-cycle may be repeated once, twice, or more times. The oxygen reactant may be the same in each sub-cycle, or may be different in one or more sub-cycles. Although referred to as the first, second, and third sub-cycles, the sub-cycles may be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed may vary independently in the super cycle. For example, the number of times one or more sub-cycles are performed may be changed to achieve a desired composition. The number of times each sub-cycle is performed in each super cycle may be the same or different. The super cycle can be repeated once, twice or more times to obtain a MIZO layer of desired thickness and composition. A deposition super cycle comprising three sub-cycles can be written as {[Indium Precursor + Oxygen Reactant] x N1 + [Zinc Precursor + Oxygen Reactant] x N2 + [Magnesium Precursor + Oxygen Reactant] x N3} x N4, where N is an integer. As will be used in the detailed description below, square brackets represent one ALD sub-cycle, while curved brackets represent one super cycle.

[0065] In some embodiments, annealing in an oxygen ambient is included in a super cycle, and a deposition super cycle including three sub-cycles can be written as {[Indium Precursor + Oxygen Reactant] x N1 + [Zinc Precursor + Oxygen Reactant] x N2 + [Magnesium Precursor + Oxygen Reactant] x N3} + [Oxygen Reactant Annealing] x N4} x N5, where N is an integer. Such an oxygen reactant annealing step can be included in any deposition cycle described herein.

[0066] In some embodiments, one or more sub-cycles may be repeated multiple times relative to one or more other sub-cycles. For example, in some embodiments, the indium oxide sub-cycle and the zinc oxide sub-cycle may be repeated a certain number of times relative to the magnesium oxide sub-cycle. Such a super cycle may be written as {[(indium precursor + oxygen reactant) x N1 + (zinc precursor + oxygen reactant) x N2] x N3 + [magnesium precursor + oxygen reactant] x N4} x N5, where N1, N2, N3, N4, and N5 are integers.

[0067] In some embodiments, the MIZO deposition super cycle includes a first indium zinc oxide (IZO) sub-cycle, in which the substrate is contacted alternately and sequentially with an indium precursor, a zinc precursor, and an oxygen reactant. The precursors may be provided in any order. The first sub-cycle may be repeated once, twice, or more times. In the second magnesium oxide sub-cycle, the substrate is contacted alternately and sequentially with a magnesium precursor and an oxygen reactant. The second sub-cycle may be repeated once, twice, or more times. The oxygen reactant may be the same in each sub-cycle, or may be different in one or more sub-cycles. Although referred to as the first and second sub-cycles, the sub-cycles may be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed may vary independently in the super cycle. For example, the number of times one or more sub-cycles are performed may be changed to achieve a desired composition. The number of times each sub-cycle is performed in each super cycle may be the same or different. The super cycle may be repeated once, twice, or more times to obtain a MIZO layer of desired thickness and composition. A super cycle consisting of two sub-cycles can be written as {[Indium precursor + Zinc precursor + Oxygen reactant] x N1 + [Magnesium precursor + Oxygen reactant] x N2} x N3, where N1, N2 and N3 are integers.

[0068] In some embodiments, the MIZO deposition super cycle includes two sub-cycles, wherein in the first magnesium zinc oxide (MZO) sub-cycle, the substrate is contacted alternately and sequentially with a zinc precursor, a magnesium precursor, and an oxygen reactant. The precursors may be provided in any order. The first sub-cycle may be repeated once, twice, or more times. In the second indium oxide sub-cycle, the substrate is contacted alternately and sequentially with an indium precursor and an oxygen reactant. The second sub-cycle may be repeated once, twice, or more times. The oxygen reactant may be the same in each sub-cycle, or may be different in one or more sub-cycles. Although referred to as the first and second sub-cycles, the sub-cycles may be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed may vary independently in the super cycle. For example, the number of times one or more sub-cycles are performed may be changed to achieve a desired composition. The number of times each sub-cycle is performed in each super cycle may be the same or different. The super cycle may be repeated once, twice, or more times to obtain a MIZO layer of desired thickness and composition. A super cycle consisting of two sub-cycles can be written as {[zinc precursor + magnesium precursor + oxygen reactant] x N1 + [indium precursor + oxygen reactant] x N2} x N3, where N1, N2 and N3 are integers.

[0069] In some embodiments, the MIZO deposition super cycle includes two sub-cycles, wherein in the first zinc oxide sub-cycle, the substrate is contacted alternately and sequentially with a zinc precursor and an oxygen reactant. The first sub-cycle may be repeated once, twice, or more times. In the second indium magnesium oxide (IMO) sub-cycle, the substrate is contacted alternately and sequentially with an indium precursor, a magnesium precursor, and an oxygen reactant. These two precursors may be provided in any order. The second sub-cycle may be repeated once, twice, or more times. The oxygen reactant may be the same in each sub-cycle, or may be different in one or more sub-cycles. Although referred to as the first and second sub-cycles, the sub-cycles may be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed may vary independently in the super cycle. For example, the number of times one or more sub-cycles are performed may be changed to achieve a desired composition. The number of times each sub-cycle is performed in each super cycle may be the same or different. The super cycle may be repeated once, twice, or more times to obtain a MIZO layer of desired thickness and composition. A super cycle consisting of two sub-cycles can be written as {[zinc precursor + oxygen reactant] x N1 + [indium precursor + magnesium precursor + oxygen reactant] x N2} x N3, where N1, N2 and N3 are integers.

[0070] In some embodiments, the deposition super cycle for producing the MIZO layer includes one or more indium zinc oxide (IZO) sub-cycles and one or more magnesium zinc oxide (MZO) sub-cycles. In the IZO sub-cycle, the substrate is contacted alternately and sequentially with an indium precursor, a zinc precursor, and an oxygen reactant. The indium precursor and the zinc precursor can be provided in any order. The IZO sub-cycle can be repeated once, twice, or more times. In the MZO sub-cycle, the substrate is contacted alternately and sequentially with a magnesium precursor, a zinc precursor, and an oxygen reactant. The magnesium precursor and the zinc precursor can be provided in any order. The MZO sub-cycle can be repeated once, twice, or more times. The oxygen reactant can be the same in each sub-cycle, or can be different in one or more sub-cycles. The IZO and MZO sub-cycles can be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed can be independently varied in the super cycle, for example, to achieve a desired stoichiometry. For example, the number of times the MZO sub-cycle is performed relative to the IZO sub-cycle can be selected to achieve a desired In / Mg ratio in the MIZO layer. The super cycle can be repeated once, twice or more times to obtain a MIZO layer of desired thickness and composition. A super cycle comprising two oxide sub-cycles can be written as {[Indium Precursor + Zinc Precursor + Oxygen Reactant] x N1 + [Magnesium Precursor + Zinc Precursor + Oxygen Reactant] x N2} x N3, where N1, N2 and N3 are integers.

[0071] In some embodiments, the deposition super cycle for producing a MIZO layer with desired properties includes one or more indium zinc oxide (IZO) sub-cycles and one or more magnesium indium zinc oxide (MIZO) sub-cycles. The IZO sub-cycle and the MIZO sub-cycle can be repeated at a selected ratio to produce a layer with desired properties. In the IZO sub-cycle, the substrate is, for example, alternately and sequentially contacted with an indium precursor, a zinc precursor, and an oxygen reactant. The indium precursor and the zinc precursor can be provided in any order, and the oxygen reactant can be provided after one or both precursors. The IZO sub-cycle can be repeated once, twice, or more times. MIZO can be formed by any deposition cycle described herein. As described herein, in the MIZO sub-cycle, the substrate is alternately and sequentially contacted with an indium precursor, a magnesium precursor, a zinc precursor, and an oxygen reactant. The indium precursor, the magnesium precursor, and the zinc precursor can be provided in any order, and the oxygen reactant can be provided after one or more precursors. The MIZO sub-cycle can be repeated once, twice, or more times, and as described above, with the IZO sub-cycle at a desired ratio. The oxygen reactant may be the same in each sub-cycle, or may be different in one or more sub-cycles. The IZO and MIZO sub-cycles may be performed in any order in the super cycle. In addition, the number of times each sub-cycle is performed may vary independently in the super cycle, for example to achieve a desired stoichiometry. For example, the number of times the MIZO sub-cycle is performed relative to the IZO sub-cycle may be selected to achieve a desired layer. The super cycle may be repeated once, twice or more times to obtain a layer of desired thickness and composition. A super cycle comprising two sub-cycles may be written as {[IZO]x N1+[MIZO]x N2}x N3, where N1, N2, and N3 are integers.

[0072] As described above, in some embodiments, the MIZO layer may include a mixture of one or more individual oxides, such as indium oxide, zinc oxide, and magnesium oxide. In some embodiments, the MIZO layer may include a mixture of one or more individual oxides, such as indium zinc oxide (IZO) and magnesium oxide.

[0073] In some embodiments, the MIZO layer may include a mixture of one or more individual oxides, such as indium oxide and magnesium zinc oxide (MZO). In some embodiments, the MIZO layer may include a mixture of one or more individual oxides, such as indium zinc oxide and magnesium indium zinc oxide (MIZO).

[0074] In some embodiments, the stoichiometry of the MIZO layer can be adjusted by adjusting the ratio of the individual oxides in the layer. In some embodiments, the desired stoichiometry of the MIZO layer is achieved by selecting the number of sub-cycles within the super cycle, for example to provide a desired In / Mg ratio, or In / Zn ratio, or Zn / Mg, or In / Zn / Mg ratio. In some embodiments, one or more indium zinc oxide (IZO) and / or magnesium zinc oxide (MZO) sub-cycles may be included in the deposition process to achieve a desired indium and magnesium content in the layer, such as a desired In / Mg ratio. In some embodiments, one or more indium zinc oxide (IZO) sub-cycles and / or magnesium oxide sub-cycles may be included in the deposition process to achieve a desired indium and magnesium content in the layer, such as a desired In / Mg ratio.

[0075] In some embodiments, additional reactants are included in one or more super cycles. The additional reactants may, for example, improve the desired electrical properties of the MIZO layer. In some embodiments, the additional reactants may be used to control carrier density or concentration. In some embodiments, the additional reactants may be used to control defect formation during deposition of the MIZO layer. In some embodiments, the additional reactants may passivate oxygen vacancies in the growing MIZO layer. In some embodiments, the additional reactants may include NH 3 、N 2 O、NO 2 and H 2 O 2 One or more of .

[0076] In some embodiments, the additional reactant is included in one, two or more sub-cycles in the super cycle. In some embodiments, in at least one super cycle, the additional reactant is included in each sub-cycle. In some embodiments, the additional reactant is provided separately in at least one super cycle, such as after completing a sub-cycle and before starting the next sub-cycle.

[0077] In each of the above-mentioned sub-cycles, the additional reactant may be provided together with the oxygen reactant or after the oxygen reactant. In some embodiments, the additional reactant may be provided alternately and sequentially after the oxygen reactant. For example, a sub-cycle including an additional reactant may be written as [metal precursor (zinc, indium or magnesium) + oxygen reactant + additional reactant] x N1, where N is an integer. In some embodiments, the additional reactant may be provided together with the oxygen reactant, such as in the order: [metal precursor (zinc, indium or magnesium) + (oxygen reactant + additional reactant)] x N1, where N1 is an integer. That is, in some embodiments, the additional reactant is provided simultaneously with the oxygen reactant. In some embodiments, the additional reactant may flow continuously throughout the deposition sub-cycle, or even throughout the deposition super-cycle.

[0078] In some embodiments, additional reactants are provided in one or more binary oxide sub-cycles. In some embodiments, additional reactants are provided in the zinc oxide sub-cycle. For example, the zinc oxide sub-cycle can be written as [zinc precursor + oxygen reactant + additional reactant] x N1, where N1 is an integer. In some embodiments, additional reactants are provided in the indium oxide sub-cycle. For example, the indium oxide sub-cycle can be written as [indium precursor + oxygen reactant + additional reactant] x N1, where N1 is an integer. In some embodiments, additional reactants are provided in the magnesium oxide sub-cycle. For example, the magnesium oxide sub-cycle can be written as [magnesium precursor + oxygen reactant + additional reactant] x N1, where N1 is an integer. As described above, in some embodiments, additional reactants can be provided simultaneously with the oxygen reactant.

[0079] In some embodiments, additional reactants may be provided in the IZO and / or MZO sub-cycles. Such an IZO sub-cycle may be given, for example, as [indium precursor + zinc precursor + oxygen reactant + additional reactant] x N, where N is an integer. Such an MZO sub-cycle may be given, for example, as [magnesium precursor + zinc precursor + oxygen reactant + additional reactant] x N, where N is an integer. In some embodiments, the MIZO super-cycle may include an IZO sub-cycle and an MZO sub-cycle, each of which uses an additional reactant. This may be given as [indium precursor + zinc precursor + oxygen reactant + additional reactant] x N1 + [magnesium precursor + zinc precursor + oxygen reactant + additional reactant] x N2, where N is an integer. As described above, in some embodiments, additional reactants may be provided simultaneously with oxygen reactants. In some embodiments, additional reactants may flow through one or two sub-cycles, or even through a super-cycle.

[0080] In some embodiments, a dopant precursor is included in one or more super cycles. The dopant precursor can, for example, improve the desired electrical properties of the MIZO layer. In some embodiments, the dopant precursor can be used to enhance the thermal stability of the MIZO channel layer, such as the thermal stability during the annealing process. Therefore, the MIZO layer described herein can include one or more dopants.

[0081] In some embodiments, for example in a MIZO layer, the dopant concentration is from at least 10 -15 atom % to at most 10 atom %, for example from at least 10 -15 Atom% up to 10 -14 atomic %, for example from at least 10 -15 Atom% up to 10 -14 atomic %, for example from at least 10 -14 Atom% up to 10 -13 atomic %, for example from at least 10 -13 Atom% up to 10-12 atomic %, for example from at least 10 -12 Atom% up to 10 -11 atomic %, for example from at least 10 -11 Atom% up to 10 -10 atomic %, for example from at least 10 -10 Atom% up to 10 -9 atomic %, for example from at least 10 -9 Atom% up to 10 -8 atomic %, for example from at least 10 -8 Atom% up to 10 -7 atomic %, for example from at least 10 -7 Atom% up to 10 -6 atomic %, for example from at least 10 -6 Atom% up to 10 -5 atomic %, for example from at least 10 -5 Atom% up to 10 -4 atomic %, for example from at least 10 -4 Atom% up to 10 -3 atomic %, for example from at least 10 -3 Atom% up to 10 -2 atomic %, for example from at least 10 -2 Atom% up to 10 -1 atomic %, for example from at least 10 -1 At % to at most 1 atom %, for example from at least 1 atom % to at most 10 atom %.

[0082] In some embodiments, the dopant precursor is included in one, two or more sub-cycles in the super cycle. In some embodiments, the dopant precursor is included in each sub-cycle of at least one super cycle. In some embodiments, the dopant precursor is provided separately in at least one super cycle, for example, after completing a sub-cycle and before starting the next sub-cycle. In some embodiments, the dopant precursor can be provided in a separate pulse. Alternatively, the dopant precursor can be provided together with one or more other precursors. Optionally, the dopant precursor pulse is separated from other pulses by purging. In each of the above sub-cycles, the dopant precursor can be provided together with the indium precursor, the magnesium precursor and / or the zinc precursor, or provided after the indium precursor, the magnesium precursor and / or the zinc precursor. In some embodiments, the dopant precursor can be provided alternately and sequentially after the zinc precursor, the magnesium precursor and / or the indium precursor. In some embodiments, the dopant precursor can flow before the deposition super cycle. In some embodiments, the dopant precursor can flow after the deposition super cycle. In other words, in some embodiments, the dopant precursor can flow before or after the MIZO layer is deposited. In such embodiments, one or more monolayers or sub-monolayers (ie, portions of a monolayer) of dopant atoms may be formed, which may diffuse into the MIZO layer during subsequent thermal processing, such as during a forming gas anneal.

[0083] In some embodiments, the dopant precursor is provided in one, two, or more binary oxide sub-cycles. In some embodiments, the dopant precursor is provided in an indium oxide sub-cycle. In some embodiments, the dopant precursor is provided in a zinc oxide sub-cycle. In some embodiments, the dopant precursor is provided in a magnesium oxide sub-cycle. In some embodiments, the dopant precursor may be provided in an IZO and / or MZO sub-cycle. In some embodiments, the dopant precursor is provided between two sub-cycles.

[0084] In some embodiments, the dopant precursor is selected from a tantalum precursor, a cerium precursor, a germanium precursor, and a silicon precursor. Advantageously, in some embodiments, the doped MIZO layer produces a MIZO layer with improved thermal resistance relative to an undoped layer. In addition, the addition of one or more doping species can advantageously affect the electrical properties of the MIZO layer, such as one or more of the band gap, carrier concentration, and mobility.

[0085] In some embodiments, the MIZO deposition super cycle includes a surface modification step in which the substrate is contacted with a surface modifier. The surface modification can activate or deactivate the surface state on the substrate, thereby affecting the amount of precursor chemically adsorbed on the substrate in a subsequent step of providing the precursor. The surface modification step can be performed at any suitable time in the MIZO deposition super cycle. For example, the substrate can be contacted with a surface modifier before the substrate is contacted with an indium precursor. Additionally or alternatively, the substrate can be contacted with a surface modifier before the substrate is contacted with a magnesium precursor. Additionally or alternatively, the substrate can be contacted with a surface modifier before the substrate is contacted with a zinc precursor. Additionally or alternatively, the substrate can be contacted with a surface modifier before the substrate is contacted with an oxygen reactant. This can advantageously reduce the growth of each cycle of one or more layer-forming sub-cycles so that a given composition can be achieved in the main cycle with a minimum number of total sub-cycles. In other words, the use of a surface modifier can improve mixing and avoid or reduce composition changes along the growth direction.

[0086] In some embodiments, the surface modification step is performed before the substrate is contacted with any precursor. In other words, in some embodiments, the substrate is contacted with the surface modifier before the substrate is contacted with the indium precursor, the zinc precursor, and / or the magnesium precursor. In other embodiments, the surface modification step is performed after performing any of the foregoing sub-cycles, such that the surface modification step is performed on metal oxides (e.g., indium oxide, zinc oxide, magnesium oxide, indium zinc oxide, magnesium zinc oxide, and magnesium indium zinc oxide).

[0087] In some embodiments, the surface modifier can react with OH groups on the surface of the substrate. Exemplary surface modifiers include alcohols and anhydrides. Suitable alcohols include methanol, ethanol and / or isopropanol. Suitable anhydrides include formic anhydride and acetic anhydride.

[0088] In some embodiments, the indium precursor includes an alkyl ligand. In some embodiments, the alkyl ligand includes a branched or straight chain hydrocarbon group containing 1-10 carbon atoms. In some embodiments, the alkyl ligand includes an alkylamino or alkoxy substituent that can be bonded to the indium atom through a heteroatom (i.e., N or O). In some embodiments, the ligand is a 3-(dimethylamino)propyl group or a 3-(diethylamino)propyl group. In some embodiments, the indium precursor is trimethyl indium. In some embodiments, the indium precursor is triethyllinium. In some embodiments, the indium precursor is ethyl dimethyl indium. In some embodiments, the indium precursor is InMe2(CH2CH2CH2NMe2), InEt2(CH2CH2CH2NMe2), InMe2(CH2CH2CH2NEt2) or InEt2(CH2CH2CH2NEt2).

[0089] In some embodiments, the indium precursor comprises a halogen ligand. In some embodiments, the halogen ligand is a chloride. In some embodiments, the indium precursor comprises InCl or InCl3. In some embodiments, the indium precursor is InMe2Cl.

[0090] In some embodiments, the indium precursor includes a cyclopentadienyl (Cp) or a substituted cyclopentadienyl ligand. In some embodiments, the substituent on Cp includes one or more of the following groups: methyl, ethyl, isopropyl, n-propyl, isobutyl, tert-butyl, n-butyl, sec-butyl, trimethylsilyl, pentyl, cyclopentyl, hexyl, cyclohexyl, 2-dimethylaminoethyl, 3-dimethylaminopropyl, 2-methoxyethyl or 3-methoxypropyl. In some embodiments, the indium zinc precursor is InCp. In some embodiments, the indium precursor is In(EtCp). In some embodiments, the indium precursor is In(CpCH2CH2NMe2) or In(cpch2ch2 NME 2). In some embodiments, the indium precursor is InMe2(CpCH2CH2NMe2) or InMe2(CpCH2CH2CH2NMe2). In some embodiments, the indium precursor is In(CpCH2CH2OMe) or In(CpCH2CH2CH2OMe). In some embodiments, the indium precursor is InMe2(CpCH2CH2OMe) or InMe2(CpCH2CH2CH2OMe).

[0091] In some embodiments, the indium precursor includes an alkoxide ligand. In some embodiments, the alkoxide ligand is isopropanol. In some embodiments, the alkoxide ligand is tert-butyl alkoxide. In some embodiments, the alkoxide ligand is ditert-butyl pentoxide. In some embodiments, the ligand is 1-(dimethylamino)-2-propanol ester (dmap). In some embodiments, the ligand is 1-(dimethylamino)-2-methyl-2-propanol (dmamp). In some embodiments, the ligand is 1-(dimethylamino)-2-methyl-2-butoxy (dmamb). In some embodiments, the precursor is tri(tert-pentyloxy)indium(III). In some embodiments, the indium precursor is tri(tert-butoxy)indium(III). In some embodiments, the indium precursor is tri(isopropoxy)indium(III). In some embodiments, the indium precursor is In(dmap)3, In(dmamp)3 or In(dmamb)3. In some embodiments, the indium precursor is InMe2(dmap), InMe2(dmamp) or InMe2(dmamb). In some embodiments, the indium precursor is InEt2(dmap), InEt2(dmamp), or InEt2(dmamb). In some embodiments, the indium precursor is In(dmamp)2(OiPr).

[0092] In some embodiments, the indium precursor includes an amide ligand. In some embodiments, the ligand is dimethylamide. In some embodiments, the ligand is diethylamide. In some embodiments, the ligand is ethylmethylamide. In some embodiments, the ligand is bis(trimethylsilyl)amide. In some embodiments, the indium precursor is InMe2(NMe2), InMe2(NEt2) or InMe2(NEtMe). In some embodiments, the indium precursor is InEt2(NMe2), InEt2(NEt2) or InEt2(NEtMe). In some embodiments, the indium precursor is InMe2[N(SiMe3)2]. In some embodiments, the indium precursor is InEt2[N(SiMe3)2].

[0093] In some embodiments, the indium precursor includes an amidino or guanidino ligand. In some embodiments, the ligand is N,N'-di-tert-butylacetamidine (tBu2AMD). In some embodiments, the ligand is N,N'-diisopropylacetamidine (iPr2AMD). In some embodiments, the ligand is N,N'-di-tert-amylacetamide (tPn2AMD). In some embodiments, the ligand is N,N'-di-sec-butylacetamidine (sBu2AMD). In some embodiments, the ligand is N,N'-di-tert-butylformamide (tBu2FMD). In some embodiments, the ligand is N,N'-diisopropylformamide (iPr2FMD). In some embodiments, the ligand is N,N'-di-tert-amylformamide (tPn2FMD). In some embodiments, the ligand is N,N'-di-sec-butylformamide (sBu2FMD). In some embodiments, the indium precursor is In(sBu2AMD)3, In(tBu2AMD)3, In(iPr2AMD)3, or In(tPn2AMD)3. In some embodiments, the indium precursor is In(tBu2FMD)3, In(iPr2FMD)3, In(tPn2FMD)3, or In(sBu2FMD)3. In some embodiments, the indium zinc precursor is a molecule of the formula InR2L, wherein R is a methyl or ethyl ligand, and wherein L is selected from tBu2AMD, iPr2AMD, tPn2AMD, sBu2AMD, tBu2FMD, iPr2FMD, tPn2FMD, or sBu2FMD.

[0094] In some embodiments, the indium precursor includes a β-diketone ligand. In some embodiments, the ligand is acetylacetonate (acac), 2,2,6,6-tetramethyl-3,5-heptanedione (thd) or 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac). In some embodiments, the indium precursor is In(thd)3. In some embodiments, the indium precursor is In(acac)3. In some embodiments, the indium precursor is In(hfac)3.

[0095] In some embodiments, the indium precursor includes a triazene ligand. In some embodiments, the indium precursor is tris(di-tert-butyltriazene)indium(III).

[0096] In some embodiments, the zinc precursor includes an alkyl ligand. In some embodiments, the ligand is selected from methyl, ethyl, propyl or butyl. In some embodiments, the ligand is an alkyl containing an alkylamino or alkoxy substituent, wherein the N or O atom is bonded to the Zn atom. In some embodiments, the ligand is 3-(N,N-dimethylamino)propyl, 3-(N,N-diethylamino)propyl or 3-(N,N-ethylmethylamino)propyl. In some embodiments, the ligand is 3-(methoxy)propyl, 3-(ethoxy)propyl, 3-(isopropoxy)propyl or 3-(tert-butoxy)propyl. In some embodiments, the zinc precursor is dimethyl zinc. In some embodiments, the zinc precursor is diethyl zinc. In some embodiments, the zinc precursor is bis[3-(N,N-dimethylamino)propyl]zinc. In some embodiments, the zinc precursor is bis[3(methoxy)propyl]zinc. In some embodiments, the zinc precursor is bis[3-(ethoxy)propyl]zinc.

[0097] In some embodiments, the zinc precursor comprises a halide ligand. In some embodiments, the halide is a chloride. In some embodiments, the halide is a bromide or an iodide. In some embodiments, the zinc precursor is ZnCl2. In some embodiments, the zinc precursor is ZnBr2 or ZnI2.

[0098] In some embodiments, the zinc precursor comprises a β-diketonate ligand. In some embodiments, the ligand is acetylacetonate (acac), 2,2,6,6-tetramethyl-3,5-heptanedione (thd), or 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac). In some embodiments, the zinc precursor is Zn(thd)2, Zn(acac)2, or Zn(hfac)2.

[0099] In some embodiments, the zinc precursor includes an alkoxide or aminoalkoxide ligand. In some embodiments, the alkoxide ligand is selected from methoxide, ethoxide, isopropoxide or tert-butoxide. In some embodiments, the ligand is 1-(dimethylamino)-2-peroxide (dmap). In some embodiments, the ligand is 1-(dimethylamino)-2-methyl-2-propanol (dmamp). In some embodiments, the ligand is 1-(dimethylamino)-2-methyl-2-butoxy (dmamb). In some embodiments, the ligand is 4-dimethylamino-2-butoxide (dab). In some embodiments, the ligand is 4-dimethylamino-2-methyl-2-butoxy (damb). In some embodiments, the ligand is 4-dimethylamino-2-methyl-2-pentoxide (damp). In some embodiments, the ligand is 4-dimethylamino-2,3-dimethyl-2-butoxy (dadb). In some embodiments, the zinc precursor is selected from Zn(dmap)2, Zn(dmamp)2, Zn(dmamb)2, Zn(dab)2, Zn(damb)2, Zn(damp)2, or Zn(dadb)2. In some embodiments, the zinc precursor is ZnMe(OiPr).

[0100] In some embodiments, the zinc precursor comprises an amide ligand. In some embodiments, the ligand is dimethylamide. In some embodiments, the ligand is diethylamide. In some embodiments, the ligand is ethylmethylamide. In some embodiments, the ligand is bis(trimethylsilyl)amide. In some embodiments, the zinc precursor is bis(trimethylsilylamino)zinc.

[0101] In some embodiments, the zinc precursor comprises a carboxylate ligand. In some embodiments, the ligand is acetate. In some embodiments, the ligand is trimethyl acetate. In some embodiments, the zinc precursor is zinc acetate.

[0102] In some embodiments, the zinc precursor comprises a ketimine ligand. In some embodiments, the zinc precursor is selected from bis(N-(3'-dimethylaminopropyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(3'-dimethylaminoethyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(3'-ethoxypropyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(2'-ethoxyethyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(3'-methoxypropyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(2'-methoxyethyl)-2-penten-2-one-4-imino)zinc(II), or bis(N-(n-propyl)-2-penten-2-one-4-imino)zinc(II).

[0103] In some embodiments, the magnesium precursor comprises cyclopentadienyl (Cp) or substituted cyclopentadienyl ligands. In some embodiments, the substituents on Cp include one or more of the following groups: methyl, ethyl, isopropyl, n-propyl, isobutyl, tert-butyl, n-butyl, sec-butyl, trimethylsilyl, triethylsilyl, neopentyl, tert-pentyl, n-pentyl, cyclopentyl, 3-pentyl, isopentyl, n-hexyl, cyclohexyl, phenyl, tolyl, xylyl, 2-dimethylaminoethyl, 3-dimethylaminopropyl, 2-methoxyethyl or 3-methoxypropyl. In some embodiments, the magnesium precursor is MgCp2. In some embodiments, the magnesium precursor is Mg(MeCp)2 or Mg(EtCp)2.

[0104] In some embodiments, the magnesium precursor comprises a β-diketone ligand. In some embodiments, the ligand is acetylacetonate (acac), 2,2,6,6-tetramethyl-3,5-heptanedione (thd) or 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac). In some embodiments, the magnesium precursor is Mg(thd)2. In some embodiments, the magnesium precursor is Mg(acac)2. In some embodiments, the magnesium precursor is Mg(hfac)2.

[0105] In some embodiments, the magnesium precursor includes an amidine ligand. In some embodiments, the ligand is N,N'-di-tert-butylacetamidine (tBu2AMD). In some embodiments, the ligand is N,N'-diisopropylacetamidine (iPr2AMD). In some embodiments, the ligand is N,N'-di-tert-amylacetamide (tPn2AMD). In some embodiments, the ligand is N,N'-di-sec-butylacetamidine (sBu2AMD). In some embodiments, the ligand is N,N'-di-tert-butylformamide (tBu2FMD). In some embodiments, the ligand is N,N'-diisopropylformamide (iPr2FMD). In some embodiments, the ligand is N,N'-di-tert-amylformamide (tPn2FMD). In some embodiments, the ligand is N,N'-di-sec-butylformamide (sBu2FMD). In some embodiments, the magnesium precursor is Mg(sBu2AMD)2. In some embodiments, the magnesium precursor is Mg(tBu2AMD)2. In some embodiments, the magnesium precursor is Mg(iPr2AMD)2. In some embodiments, the magnesium precursor is Mg(tPn2AMD)2. In some embodiments, the magnesium precursor is Mg(sBu2FMD)2. In some embodiments, the magnesium precursor is Mg(tBu2FMD)2. In some embodiments, the magnesium precursor is Mg(iPr2FMD)2. In some embodiments, the magnesium precursor is Mg(tPn2FMD)2.

[0106] In some embodiments, the magnesium precursor includes a diazadiene (DAD) ligand, i.e., 1,4-diaza-1,3-diene. In some embodiments, the DAD ligand may be in neutral, monoanionic or dianionic form. In some embodiments, the DAD ligand is substituted by an alkyl group on one or both nitrogen atoms thereof. In some embodiments, the alkyl group is an isopropyl group. In some embodiments, the alkyl group is a tert-butyl group. In some embodiments, the alkyl group is a tert-amyl group. In some embodiments, the alkyl group is a sec-butyl group. In some embodiments, the magnesium precursor is Mg(tBu2DAD)2. In some embodiments, the magnesium precursor is Mg(sBu2DAD)2. In some embodiments, the magnesium precursor is Mg(iPr2DAD)2. In some embodiments, the magnesium precursor is Mg(tPn2DAD)2.

[0107] In some embodiments, the oxygen reactant includes one or more of water, ozone, H2O2, O2, oxygen radicals, oxygen plasma, NO2, NO, and other compounds containing N and O but not containing metals or semimetals. In some embodiments, the oxygen reactant is water. In some embodiments, the oxygen reactant is NO. In some embodiments, as described above, one or more oxygen reactants are used during the deposition process to react with one or more indium, zinc, or magnesium precursors to form the corresponding oxides. For example, the oxygen reactant can be used in a binary oxide sub-cycle with one of the indium, zinc, or magnesium precursors, or in a multi-component oxide sub-cycle, such as a sub-cycle to form IZO, MZO, or MIZO, such as to adjust the stoichiometry or composition of the layer or the desired properties.

[0108] In some embodiments, the MIZO layer is deposited to a thickness of 200 nm or less, about 100 nm or less, about 50 nm or less, about 30 nm or less, about 20 nm or less, about 10 nm or less, about 5 nm or less, or about 3 nm or less. The MIZO layer will include material deposited in at least one deposition cycle.

[0109] Atomic layer deposition allows for conformal deposition of the MIZO layer. In some embodiments, the MIZO layer is deposited on a three-dimensional structure and has a conformality of at least 90%, 95%, or more. In some embodiments, the MIZO layer is approximately 100% conformal.

[0110] In some embodiments, in structures having a high aspect ratio, the MIZO layer formed has a step coverage greater than about 80%, greater than about 90%, and greater than about 95%. In some embodiments, the high aspect ratio structure has an aspect ratio greater than about 3:1 when comparing the depth or height of the feature to the width. In some embodiments, the structure has an aspect ratio greater than about 5:1, an aspect ratio of 10:1, an aspect ratio of 20:1, an aspect ratio of 40:1, an aspect ratio of 60:1, an aspect ratio of 80:1, an aspect ratio of 100:1, an aspect ratio of 150:1, an aspect ratio of 200:1 or more.

[0111] In some embodiments, the formed MIZO layer has a carbon impurity concentration of less than 20 atomic%, less than 10 atomic%, less than 5 atomic%, less than 2 atomic%, less than 1 atomic%, or less than 0.5 atomic%. In some embodiments, the formed MIZO layer has a carbon impurity concentration of less than 30 atomic%, less than 20 atomic%, less than 10 atomic%, less than 5 atomic%, less than 3 atomic%, or less than 1 atomic%.

[0112] In some embodiments, the deposited MIZO layer has a stoichiometric or elemental ratio (In:Mg:Zn) of about 1:1:1, or 0.1:1:1 to 10:1:1, or 1:0.1:1 to 1:10:1, or 1:1:0.1 to 1:1:10, or 0.1:0.1:1 to 10:10:1, or 0.1:1:0.1 to 10:1:10, or 1:0.1:0.1 to 10:1:10. In some embodiments, the formed MIZO layer has a stoichiometric ratio or element ratio (In:Mg:Zn) of 0.01:1:1 to 100:1:1, or 1:0.01:1 to 1:100:1, or 1:1:0.01 to 1:1:100, or 0.01:0.01:1 to 100:100:1, or 0.01:1:0.01 to 100:1:100, or 1:0.01:0.01 to 1:100:100. The ZMO, IMO and IZO layers can each achieve the same ratio (without the excluded metal components).

[0113] In some embodiments, the MIZO layer formed by the method of the present disclosure has an indium content (atomic %) of less than 80 atomic % or less than 70 atomic % or less than 60 atomic % or less than 50 atomic % or less than 40 atomic % or less than 30 atomic % or less than 20 atomic % or less than 10 atomic %. In some embodiments, the MIZO layer formed by the method of the present disclosure has an indium content (atomic %) between 80 atomic % and 10 atomic %, or between 70 atomic % and 20 atomic %, or between 60 atomic % and 30 atomic %.

[0114] In some embodiments, the MIZO layer formed by the method of the present disclosure has a magnesium content (atomic %) of less than 80 atomic % or less than 70 atomic % or less than 60 atomic % or less than 50 atomic % or less than 40 atomic % or less than 30 atomic % or less than 20 atomic % or less than 10 atomic %. In some embodiments, the MIZO layer formed by the method of the present disclosure has a magnesium content (atomic %) between 80 atomic % and 10 atomic %, or between 70 atomic % and 20 atomic %, or between 60 atomic % and 30 atomic %.

[0115] In some embodiments, the MIZO layer formed by the method of the present disclosure has a zinc content (atomic %) of less than 40 atomic %, less than 30 atomic %, less than 20 atomic %, less than 15 atomic %, less than 10 atomic %, or less than 5 atomic %. In some embodiments, the zinc content (atomic %) of the MIZO layer formed by the method of the present disclosure is between 40 atomic % and 5 atomic %, or between 30 atomic % and 10 atomic %, or between 20 atomic % and 15 atomic %.

[0116] In some embodiments, a MIZO layer is formed with a thickness non-uniformity (1 sigma standard deviation) of less than 10%, less than 5%, less than 2%, less than 1%, or less than 0.5% in a 200 or 300 mm wafer or other substrate like a square substrate.

[0117] In some embodiments, in a 200 or 300 mm wafer or other substrate like a square substrate, the MIZO layer formed has an elemental composition non-uniformity (metal atom concentration non-uniformity) of less than 30%, less than 20%, less than 10%, less than 5%, less than 2%, less than 1%, or less than 0.5% in the substrate surface direction.

[0118] In some embodiments, the MIZO layer deposited by the process disclosed herein is annealed after deposition, depending on the needs of the application. In some embodiments, the MIZO layer is annealed in an oxygen environment. For example, these layers can be annealed at high temperatures in water, O2, or any other oxygen reactant described above. In some embodiments, these layers can be annealed in an oxygen reactant including oxygen plasma, oxygen free radicals, atomic oxygen, or excited oxygen species. In some embodiments, these layers are annealed in a hydrogen-containing environment or an inert atmosphere, such as N2, Ar, or He atmosphere. In some embodiments, these layers are annealed in a synthetic gas. In some embodiments, the annealing step is not performed.

[0119] In some embodiments, after the MIZO deposition, another layer is deposited. The additional layer can be directly on top of and in contact with the ALD deposited MIZO layer.

[0120] Although certain embodiments and examples have been discussed, it will be understood by those skilled in the art that the scope of the claims extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses and obvious modifications and equivalents thereof. Indeed, various modifications of the present disclosure, such as alternative useful combinations of the described elements, in addition to those shown and described herein, will become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.

[0121] In the present disclosure, where conditions and / or structures are not specified, those skilled in the art can readily provide such conditions and / or structures as routine experimentation in view of the present disclosure.

Claims

1. A method for forming a magnesium indium zinc oxide (MIZO) layer, the method comprising: placing a substrate in a reaction chamber; A cyclic deposition process comprising a plurality of repeated deposition cycles is performed, wherein the deposition cycles comprise: (a) contacting a substrate with a vapor phase indium precursor; (b) contacting the substrate with a vapor phase zinc precursor; (c) contacting the substrate with a vapor phase magnesium precursor; and (d) contacting the substrate with an oxygen reactant.

2. The method according to claim 1, wherein: The deposition cycle includes an indium oxide sub-cycle, a zinc oxide sub-cycle and a magnesium oxide sub-cycle.

3. The method according to claim 2, wherein: The oxygen reactant contacts the substrate after step (a), after step (b), and after step (c).

4. The method according to claim 1, wherein: A unit deposition cycle includes an indium oxide sub-cycle and a magnesium zinc oxide sub-cycle.

5. The method according to claim 4, wherein: The oxygen reactant contacts the substrate after step (a) and after steps (b) and (c) are completed.

6. The method according to claim 5, wherein: The MIZO layer includes a mixture of indium oxide and magnesium zinc oxide.

7. The method according to claim 1, wherein: The MIZO layer has a magnesium content of less than 40 atomic %.

8. The method according to claim 1, wherein: The cyclic deposition process is carried out at a deposition temperature below 250°C.

9. The method according to claim 1, wherein: The vapor phase indium precursor includes a ligand selected from the group consisting of alkyl, alkylamino, alkoxy, halide, cyclopentadienyl (Cp), alkoxide, amide, amidine, guanidinyl, β-diketonate, and triazene.

10. The method according to claim 9, wherein: The gas phase indium precursor is selected from trimethyl indium, triethyl indium, ethyl dimethyl indium, InMe2(CH2CH2CH2NMe2), InEt2(CH2CH2CH2NMe2), InMe2(CH2CH2CH2NEt2), InEt2(CH2CH2CH2NEt2), InCl, InCl3, InMe2Cl, In(CpCH2CH2NMe2), In(CpCH2CH2CH2NMe2), InMe2(CpCH2CH2NMe2), InMe2(CpCH2CH2 H2NMe2), In(CpCH2CH2OMe), In(CpCH2CH2CH2OMe), InMe2(CpCH2CH2OMe), InMe2(CpCH2CH2OMe, tri(tert-butoxy)indium(III), tri(tert-butoxy)indium(III), tri(isopropoxy)indium(III), In(dmap)3, In(dmamp)3, In(dmamb3, InMe2(dmap), InMe2(dmamp), InMe2(dmamb), InEt2(d map), InEt2(dmamp), InEt2(dmamb), In(dmamp)2(OiPr), InMe2(NMe2), InMe2(NEt2), InMe2(NEtMe), InEt2(NMe2), InEt 2(NEt2), InEt2(NEtMe), InMe2[N(SiMe3)2], InEt2[N(SiMe3)2], In(sBu2AMD)3, In(tBu2AMD)3, In(iPr2AMD)3 or In(tPn2 AMD)3, In(tBu2FMD)3, In(iPr2FMD)3, In(tPn2FMD)3, In(thd)3, In(acac)3, In(hfac)3, as well as tri(di-tert-butyltriazene)indium(III), In(sBu2FMD)3 and an indium precursor represented by InR2L, wherein R is a methyl or ethyl ligand, and wherein L is selected from tBu2AMD, iPr2AMD, tPn2AMD, sBu2AMD, tBu2FMD, iPr2FMD, tPn2FMD and sBu2FMD.

11. The method according to claim 1, wherein: The vapor phase zinc precursor comprises a ligand selected from the group consisting of alkyl, alkylamino, alkoxy, halide, cyclopentadienyl (Cp), alkoxide, aminoalkoxide, amide, carboxylate, and ketimine.

12. The method according to claim 11, wherein: The vapor phase zinc precursor is selected from the group consisting of dimethyl zinc, diethyl zinc, bis[3-(N,N-dimethylamino)propyl]zinc, bis[3(methoxy)propyl]zinc, bis[3-(ethoxy)propyl]zinc, ZnCl2, ZnBr2, ZnI2, Zn(thd)2, Zn(acac)2, Zn(hfac)2, Zn(dmap)2, Zn(dmamp)2, Zn(dmamb)2, Zn(dab)2, Zn(damb)2, Zn(damp)2, Zn(dadb)2, ZnMe(OiPr), bis(trimethylsilylamino)zinc, zinc acetate, bis(N-(3'-dimethylaminopropyl)-2 bis(N-(3'-dimethylaminoethyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(3'-ethoxypropyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(2'-ethoxyethyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(3'-methoxypropyl)-2-penten-2-one-4-imino)zinc(II), bis(N-(2'-methoxyethyl)-2-penten-2-one-4-imino)zinc(II) and bis(N-(n-propyl)-2-penten-2-one-4-imino)zinc(II).

13. The method according to claim 1, wherein: The gas phase magnesium precursor comprises a ligand selected from cyclopentadienyl (Cp), β-diketonate, amidine, and diazadiene (DAD).

14. The method according to claim 13, wherein: The gas-phase magnesium precursor is selected from: MgCp2, Mg(MeCp)2, Mg(EtCp)2, Mg(thd)2, Mg(acac)2, Mg(hfac)2, Mg(sBu2AMD)2, Mg(tBu2AMD)2, Mg(iPr2AMD)2, Mg(tPn2AMD)2, Mg(sBu2FMD)2, Mg(tBu2FMD)2, Mg(iPr2FMD)2, Mg(tPn2FMD)2, Mg(tBu2DAD)2, Mg(sBu2DAD)2, Mg(iPr2DAD)2, Mg(tPn2DAD)2.

15. The method according to claim 1, wherein: The gas-phase oxygen reactant includes one or more of water, ozone and H2O2.

16. An atomic layer deposition (ALD) process for forming a magnesium indium zinc oxide (MIZO) layer, the ALD process comprising a deposition cycle comprising alternatingly and sequentially contacting a substrate with trimethylindium, diethylzinc, bis(cyclopentadienyl)magnesium(II), and oxygen reactants in a reaction chamber, and repeating the deposition cycle until a MIZO layer of desired thickness and composition has been formed.

17. The process of claim 16, wherein: The MIZO layer has a magnesium content of less than 40 atomic %.

18. An atomic layer deposition (ALD) method for forming a magnesium indium zinc oxide (MIZO) layer on a substrate in a reaction chamber, the method comprising: performing a deposition cycle comprising alternately and sequentially contacting the substrate with a vapor-phase indium precursor, a vapor-phase zinc precursor, a vapor-phase magnesium precursor, an oxygen reactant, and a second reactant; as well as Repeat the deposition cycle two or more times, The second reactant includes one or more of NH3, N2O, NO2 and H2O2.

19. The method according to claim 18, wherein: The substrate is contacted with the oxygen reactant and the second reactant simultaneously.

20. The process of claim 1, wherein: The MIZO layer has a magnesium content of less than 40 atomic %.

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