Si precursors for the deposition of SiN at low temperatures

Abstract

To provide methods and precursors for depositing silicon nitride films by atomic layer deposition (ALD).SOLUTION: A silicon nitride ALD deposition cycle method comprises: a step 210 of contacting a substrate with a silicon precursor such that the silicon precursor adsorbs on a substrate surface; a step 220 of contacting the substrate with a nitrogen precursor; and a step 230 of repeating the steps 210 and 220 as many times as required to achieve a thin film of a desired thickness and composition. The silicon precursor comprises an iodine ligand. The silicon nitride films have a relatively uniform etch rate for both vertical and horizontal portions when deposited on three-dimensional structures such as FinFETs or other types of multiple-gate FETs. Various silicon nitride films have an etch rate of less than half the thermal oxide removal rate with diluted HF (0.5%).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This application relates generally to the field of semiconductor device manufacturing, and more specifically to low temperature deposition of silicon nitride films and precursors for use in depositing silicon nitride films. [Background technology]

[0002] Spacers are widely used in semiconductor manufacturing as structures to protect against subsequent manufacturing steps. For example, nitride spacers formed beside a gate electrode can be used as a mask to protect the underlying source / drain regions during doping or implant steps.

[0003] As the physical features of semiconductor devices shrink, gate electrode spacers become smaller and smaller. The width of the spacers is limited by the thickness of the nitride that can be deposited over the dense gate electrode lines. Therefore, it is preferable for the nitride spacer etch process to have a high ratio of spacer width to the thickness of the deposited nitride layer. Summary of the Invention [Problem to be solved by the invention]

[0004] Modern PEALD silicon nitride processes generally experience anisotropic etching behavior when deposited on three-dimensional structures (such as trench structures). In other words, films deposited on the sidewalls of a trench or vane or other three-dimensional feature exhibit inferior film properties compared to films in the top regions of the feature. The film properties may be sufficient for applications targeting the top of a trench, or planar regions of a structured wafer, but may not be sufficient on the sidewalls or other non-horizontal or vertical surfaces.

[0005] 1A and 1B show typical examples of silicon nitride films that can be used in spacer applications. The films were deposited at 400° C. using a PEALD process other than that described in this application. FIG. 1A shows the film after deposition on a three-dimensional surface and before etching with HF. The etching process was therefore carried out by immersing the workpiece in HF (0.5%) for about 60 seconds. FIG. 1B shows that the vertical portion of the silicon nitride film is etched to a greater extent than the horizontal portion of the film. The film thickness is shown in nanometers. These structures would generally not survive further processing such as that in FinFET spacer applications. [Means for solving the problem]

[0006] In some aspects, atomic layer deposition (ALD) methods for forming silicon nitride films are provided. The ALD methods may be plasma-amplified ALD methods or thermal ALD methods. The methods allow for the deposition of silicon nitride films with desirable properties, such as good step coverage and pattern loading effects, and desirable etch characteristics. According to some embodiments, when deposited on three-dimensional structures, the silicon nitride films have relatively uniform etch rates for both vertical and horizontal portions. Such three-dimensional structures may include, for example, but are not limited to, FinFETs or other multi-gate FETs. In some embodiments, the various silicon nitride films of the present invention have etch rates in dilute HF (0.5%) that are less than half the thermal oxidation removal rate of about 2-3 nm / min.

[0007] In some embodiments, a method for depositing a silicon nitride film on a substrate in a reaction chamber includes the steps of introducing a gas phase silicon reactant into the reaction space to adsorb a silicon precursor on the substrate surface, removing excess silicon reactant, contacting the adsorbed silicon reactant with reactive species generated by a plasma from a nitrogen precursor, and removing excess reactive species and reaction by-products. These steps are repeated to obtain a silicon nitride film of a desired thickness.

[0008] In some embodiments, the silicon precursor comprises a precursor of formula (1)-(8) described herein. In some embodiments, the silicon precursor is selected from the group consisting of HSiI3, H2SiI2, H3SiI, H2Si2I4, H4Si2I2, and H5Si2I. In some embodiments, the silicon precursor is H2SiI2. The reactive species may include, for example, hydrogen, hydrogen atoms, hydrogen plasma, hydrogen radicals, N* radicals, NH* radicals, or NH2* radicals.

[0009] In some embodiments, the silicon nitride film is deposited on a three-dimensional structure. In some embodiments, the silicon nitride film exhibits at least about 80% step coverage and pattern loading effect. In some embodiments, the three-dimensional structure includes a sidewall and a top surface, and the wet etching rate (WER) of the sidewall of the silicon nitride film relative to the WER of the top surface is less than about 3 in 0.5% dHF. In some embodiments, the etching rate of the silicon nitride film is less than about 0.4 nm / min in 0.5% aqueous HF solution.

[0010] In some embodiments, the method for depositing silicon nitride film includes the steps of: filling a substrate containing at least one three-dimensional feature into a reaction space; introducing a silicon precursor into the reaction space so that the silicon precursor is adsorbed on the surface of the substrate; purging the reaction space of excess silicon precursor; purging the reaction space of excess nitrogen precursor; introducing a nitrogen precursor into the reaction space; and repeating the above steps to produce a film of desired thickness. In some embodiments, the film has a step coverage of more than about 50% on the three-dimensional feature. In some embodiments, the wet etch rate of the silicon nitride film is less than about 5 nm / min in a 5% HF aqueous solution. In some embodiments, the ratio of the etch rate of the silicon nitride film on the sidewall of the three-dimensional structure to the etch rate of the silicon nitride film on the top surface of the three-dimensional structure is less than about 4. In some embodiments, the step coverage is at least about 80% or 90%.

[0011] In some embodiments, a method for depositing a silicon nitride film on a substrate includes exposing the substrate to a gas phase silicon precursor such that the silicon precursor is adsorbed on the surface of the substrate, exposing the substrate to a purge gas and / or vacuum to remove excess precursor and reaction by-products from the substrate surface, contacting the adsorbed silicon precursor with nitrogen plasma generated species, exposing the substrate to a purge gas and / or vacuum to remove nitrogen-containing plasma and reaction by-product species from at and near the substrate surface, and repeating the above steps to produce a film of a desired thickness.

[0012] In some embodiments, a method for depositing a silicon nitride film on a substrate includes exposing the substrate to a gas-phase silicon reactant such that the gas-phase silicon reactant is adsorbed on the substrate surface, exposing the substrate to a purge gas and / or vacuum to remove excess precursor and reaction by-products from the substrate surface, contacting the adsorbed silicon reactant with a nitrogen precursor, exposing the substrate to a purge gas and / or vacuum to remove excess nitrogen precursor and reaction by-products from at or near the substrate surface, and repeating the steps to produce a film of a desired thickness.

[0013] In some embodiments, the silicon precursor comprises iodine or bromine. In some embodiments, the film has a step coverage of more than about 50%. In some embodiments, the etching rate of silicon nitride is less than about 5 nm / min in 0.5% HF aqueous solution. In some embodiments, the ratio of the etching rate of silicon nitride thin film on the sidewall of a three-dimensional structure to the etching rate of silicon nitride thin film on the top surface of the three-dimensional structure is less than about 4.

[0014] The present invention will be understood from the preferred embodiments and the accompanying drawings, which are illustrative of the invention and are not intended to limit it. [Brief description of the drawings]

[0015] [Figure 1A] FIG. 1 illustrates the results of an etching process on a silicon nitride membrane. [Figure 1B] FIG. 1 illustrates the results of an etching process on a silicon nitride membrane. [Diagram 2] FIG. 1 illustrates generally how a silicon nitride film is formed by an ALD process in some embodiments of the present invention. [Diagram 3] 1 is a flow chart illustrating a method for forming a silicon nitride thin film by a PEALD process in accordance with some embodiments of the present invention. [Figure 4] 1 is a flow chart illustrating a method for forming a silicon nitride thin film by a thermal ALD process in some embodiments of the present invention. [Figure 5A] FIG. 1 shows field emission scanning electron microscopy (FESEM) images of various silicon nitride films deposited according to some embodiments of the present invention. [Figure 5B] FIG. 1 shows field emission scanning electron microscopy (FESEM) images of various silicon nitride films deposited according to some embodiments of the present invention. [Figure 5C] FIG. 1 shows field emission scanning electron microscopy (FESEM) images of various silicon nitride films deposited according to some embodiments of the present invention. [Figure 6A] FIG. 6C shows FESEM images of the silicon nitride film of FIGS. 6A-6B after exposure to a dHF dip for 2 minutes. [Figure 6B] FIG. 6C shows FESEM images of the silicon nitride film of FIGS. 6A-6B after exposure to a dHF dip for 2 minutes. [Figure 6C] FIG. 6C shows FESEM images of the silicon nitride film of FIGS. 6A-6B after exposure to a dHF dip for 2 minutes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Silicon nitride films have a wide variety of applications, such as DRAMs in planar theory, and NAND flash devices, as will be apparent to those skilled in the art. More specifically, conformal silicon nitride thin films that exhibit uniform etching behavior have a wide variety of applications, both in and outside the semiconductor industry. In accordance with some embodiments of the present invention, various silicon nitride films and precursors and methods for depositing such films by atomic layer deposition (ALD) are provided. Importantly, in some embodiments, the silicon nitride films have relatively uniform etch rates in both vertical and horizontal portions when deposited on three-dimensional structures. In some embodiments, such three-dimensional structures may include, for example, but not limited to, FinFETs or other multi-gate FETs. In some embodiments, the various silicon nitride films of the present invention have etch rates of about 2-3 nm / min using dilute HF (0.5%), which is less than half the thermal oxidation removal rate.

[0017] The thin film layer comprising silicon nitride may be deposited by a plasma-enhanced atomic layer deposition (PEALD) type process or a thermal ALD process. In some embodiments, the silicon nitride thin film is deposited on the substrate by PEALD. In some embodiments, the silicon nitride thin film is deposited on the substrate by a thermal ALD process. The silicon nitride thin film is deposited on a three-dimensional structure. In some embodiments, the silicon nitride thin film is deposited on a three-dimensional structure (such as a wing in the formation of a finFET device).

[0018] The above chemical formula for silicon nitride is referred to generically herein for convenience and simplicity. However, those skilled in the art will appreciate that the actual chemical formula for silicon nitride, which represents the ratio of Si:N in the film, excluding hydrogen or other impurities, is SiN, as long as some Si-N bonds are formed. xwhere X varies from about 0.5 to about 2.0. In some cases, X may vary from about 0.9 to about 1.7, from about 1.0 to about 1.5, or from about 1.2 to about 1.4. In some embodiments, Si is in the +IV oxidation state and silicon nitride is formed, where the amount of nitride in the material may vary.

[0019] ALD-type processes are based on controlled, generally self-limiting, surface reactions. Gas-phase reactions are typically avoided by contacting the substrate with the reactants in an alternating and sequential manner. Gas-phase reactants are separated from one another in the reaction chamber, for example, by removing excess reactants and / or reactant by-products between reactant pulses. Reactants may be removed from the vicinity of the substrate surface using a purge gas and / or vacuum. In some embodiments, excess reactants and / or reactant by-products are removed from the reaction space, for example, by purging with an inert gas.

[0020] The methods disclosed herein provide for the deposition of thin SiN films on substrate surfaces. Challenging geometries are possible due to the nature of ALD-type processes. According to some embodiments, ALD-type processes are used to form thin SiN films on substrates, such as integrated circuit workpieces, and in some embodiments, three-dimensional structures on the substrates.

[0021] 2 is a flow chart generally illustrating ALD deposition cycles of silicon nitride that can be used to deposit silicon nitride thin films of some embodiments. In certain embodiments, the silicon nitride thin films are formed on a substrate by an ALD-type process that includes multiple silicon nitride deposition cycles, each silicon nitride deposition cycle 200: (1) contacting a substrate with a silicon precursor such that the silicon precursor is adsorbed onto the substrate surface 210; (2) contacting the substrate with a nitrogen precursor 220; and (3) repeating steps 210 and 220 as many times as necessary to obtain a thin film of the desired thickness and composition.

[0022] Excess reactants may be removed from the vicinity of the substrate, for example, by purging the reaction space with an inert gas after each contacting step. The following description describes each of these steps in more detail.

[0023] (PEALD process) In some embodiments, a plasma-enhanced ALD (PEALD) process is used to deposit SiN films. Briefly, a substrate or workpiece is placed in a reaction chamber and undergoes alternating, repeated surface reactions. In some embodiments, a SiN thin film is formed by repeated self-limiting ALD cycles. Preferably, to form a SiN film, each ALD cycle includes at least two distinct phases. The supply of reactants from the reaction space and the removal of reactants from the reaction space may be considered phases. In the first phase, a first reactant comprising silicon is provided and forms no more than about one monolayer on the substrate surface. This reactant is also referred to herein as a "silicon precursor," "silicon-containing precursor," or "silicon reactant," and may be, for example, H2SiI2.

[0024] In the second phase, a second reactant containing reactive species may be provided to convert the absorbed silicon to silicon nitride. In some embodiments, the second reactant includes a nitrogen precursor. In some embodiments, the reactive species includes an excited species. In some embodiments, the second reactant includes a nitrogen-containing plasma. In some embodiments, the second reactant includes nitrogen radicals, nitrogen atoms, and / or nitrogen plasma. The second reactant may include other species that are not nitrogen precursors. In some embodiments, the second reactant may include hydrogen plasma, hydrogen radicals, or atomic hydrogen in one form or another. In some embodiments, the second reactant may include species from a noble gas (He, Ne, Ar, Kr, or Xe, preferably Ar or He), for example, in the form of a plasma, or in the form of atoms. These reactive species from the noble gas do not necessarily contribute to the material of the deposited film, but may contribute to the growth of the film in some circumstances and may assist in the generation and ignition of the plasma. In some embodiments, the gas used to form the plasma may flow constantly throughout the deposition process, but may only be activated intermittently. In some embodiments, the second reactant does not include species derived from a noble gas (such as Ar), and thus in some embodiments, the adsorbed silicon precursor is prevented from coming into contact with reactive species generated by the Ar plasma.

[0025] Additional phases may be added or removed as needed to adjust the composition of the final film.

[0026] One or more of the reactants may be provided using a carrier gas (such as Ar or He). In some embodiments, the silicon precursor and the second reactant are provided using a carrier gas.

[0027] In some embodiments, the two phases may overlap or be combined. For example, the silicon precursor and the second reactant may be provided simultaneously in partially or completely overlapping pulses. In addition, although referred to as first and second phases, and first and second reactants, the order of the phases may be changed, and the ALD cycle may begin with any one of the phases. That is, unless otherwise stated, the reactants may be provided in any order, and the process may begin with any reactant.

[0028] As described in more detail below, in some embodiments for depositing silicon nitride films, one or more deposition cycles begin with the provision of a silicon precursor, followed by a second precursor. In other embodiments, deposition may begin with the provision of a second precursor, followed by a silicon precursor.

[0029] In some embodiments, a substrate (such as a semiconductor workpiece) on which deposition is desired is placed into a reactor. The reactor may be part of a cluster tool in which various different processes in the formation of integrated circuits occur. In some embodiments, a flow type reactor is used. In some embodiments, a showerhead type of reactor is used. In some embodiments, a spatially separated type reactor is used. In some embodiments, a high volume, manufacturable single wafer ALD reactor is used. In other embodiments, a batch reactor containing multiple substrates is used. In embodiments in which a batch ALD reactor is used, the number of substrates is preferably between 10 and 200, more preferably between 50 and 150, and most preferably between 100 and 130.

[0030] Exemplary single-wafer reactors specifically designed for amplifying ALD processes are commercially available from ASM America, Inc. (Phoenix, Ariz.) under the trade names Pulsar® 2000 and Pulsar® 3000, and from ASM Japan, Inc. (Tokyo, Japan) under the trade names Eagle® XP, XP8, and Dragon®. Exemplary batch ALD reactors specifically designed for amplifying ALD processes are commercially available from ASM Europe BV (Almere, The Netherlands) under the trade names A400™ and A412™.

[0031] In some embodiments, if necessary, the exposed surface of the workpiece is pretreated to provide reactive sites for reaction with the first phase of the ALD process. In some embodiments, a separate pretreatment step is not required. In some embodiments, the substrate is pretreated to provide a desired surface termination. In some embodiments, the substrate is pretreated with a plasma.

[0032] Excess reactants and reaction by-products, if any, are removed from the vicinity of the substrate, and particularly from the substrate surface between reactant pulses. In some embodiments, the reaction chamber is purged between reactant pulses, for example with an inert gas. The flow rate and time of each reactant can be adjusted, allowing for control of the film's properties and various characteristics.

[0033] As mentioned above, in some embodiments, the gas is continuously supplied to the reaction chamber during each deposition cycle or during the entire ALD process, and the reactive species is supplied in the gas by generating a plasma either in the reaction chamber or upstream of the reaction chamber. In some embodiments, the gas includes nitrogen. In some embodiments, the gas is nitrogen. In other embodiments, the gas may include helium or argon. In some embodiments, the gas is helium or nitrogen. The flowing gas may also serve as a purge gas for the first reactant and / or the second reactant (or reactive species). For example, the flowing nitrogen may serve as a purge gas for the first silicon precursor and serve as the second reactant (reactive species source). In some embodiments, nitrogen, argon, or helium may serve as a purge gas for the first precursor and the excited species source for converting the silicon precursor to a silicon nitride film. In some embodiments, the gas from which the plasma is generated does not include argon, and the adsorbed silicon precursor is not in contact with the reactive species generated by the Ar-derived plasma.

[0034] The above cycles are repeated until a film of desired thickness and composition is obtained. In some embodiments, deposition parameters (flow rates, flow times, purge times, and / or the reactants themselves) may be altered in one or more deposition cycles during an ALD process to obtain a film with desired characteristics. In some embodiments, hydrogen and / or hydrogen plasma is not provided in the deposition cycle or deposition process.

[0035] The term "pulse" may be understood to include providing a reactant to a reaction chamber for a period of time. The term "pulse" does not limit the length or duration of the pulse and may be of any length of time.

[0036] In some embodiments, the silicon reactant is provided first. If necessary or desired, after the initial surface termination, a first silicon reactant pulse is applied to the workpiece. According to some embodiments, the first reactant pulse includes a carrier gas flow and a volatile silicon species (such as H2SiI2) that is reactive with the workpiece surface of interest. Thus, the silicon reactant adsorbs onto these workpiece surfaces. The first reactant pulse self-saturates the workpiece surface so that excess components of the first reactant pulse do not further react with the molecular layer formed in this process.

[0037] The first silicon reactant pulse is preferably used in gaseous form. A silicon precursor gas is considered "volatile" for purposes of the present invention if the reactant species exhibits sufficient vapor pressure under process conditions to deliver the reactant species to the workpiece in sufficient concentration to fill exposed surfaces.

[0038] In some embodiments, the silicon reactant pulse is from about 0.05 seconds to about 5.0 seconds, from about 0.1 seconds to about 3 seconds, from about 0.2 seconds to about 1.0 seconds. Optimal pulse times can be readily determined by one of skill in the art based on the particular circumstances.

[0039] In some embodiments, the silicon reactant consumption rate is selected to provide a desired precursor dosage to the reaction space. Reactant consumption refers to the amount of reactant consumed from a reactant source (such as a reactant source bottle) and can be determined by weighing the reactant source before and after a certain number of deposition cycles and dividing the weight difference by the number of cycles. In some embodiments, the silicon reactant consumption is greater than about 0.1 mg / cycle. In some embodiments, the silicon reactant consumption is between about 0.1 mg / cycle and about 50 mg / cycle, between about 0.5 mg / cycle and about 30 mg / cycle, or between about 2 mg / cycle and about 20 mg / cycle. In some embodiments, the minimum preferred silicon reactant consumption may be provided at least in part by the reactor dimensions (heated surface area of ​​the reactor). In some embodiments in a showerhead reactor designed for 300 mm silicon wafers, the silicon reactant consumption is greater than about 0.5 mg / cycle or greater than about 2.0 mg / cycle. In some embodiments, the silicon reactant consumption is greater than about 5 mg / cycle in a showerhead reactor configured for 300 mm silicon wafers. In some embodiments, the silicon reactant consumption is greater than about 1 mg / cycle, preferably greater than 5 mg / cycle, in a showerhead reactor configured for 300 mm silicon wafers at reaction temperatures of about 400° C. or less.

[0040] After a sufficient time for the molecular layer to adsorb on the substrate surface, the excess first silicon reactant is removed from the reaction space. In some embodiments, the excess first reactant is purged by stopping the flow of the first chemical while continuing to flow a carrier gas or purge gas for a sufficient time to diffuse or purge the excess reactant and reactant by-products, if any, from the reaction space. In some embodiments, the excess first precursor is purged using an inert gas (nitrogen or argon) and is flowed throughout the ALD cycle.

[0041] In some embodiments, the first reactant is purged for about 0.1 seconds to about 10 seconds, about 0.3 seconds to about 5 seconds, about 0.3 seconds to about 1 second. The delivery and removal of the silicon reactant can be the first phase or silicon phase of an ALD cycle.

[0042] In a second phase, a second reactant (such as a nitrogen plasma) containing a reactive species is delivered to the workpiece. Nitrogen (N2) is, in some embodiments, continuously flowed into the reaction chamber during each ALD cycle. The nitrogen plasma may be formed by generating a plasma in the nitrogen at or upstream of the reaction chamber, for example, by flowing nitrogen through a remote plasma generator.

[0043] In some embodiments, plasma is generated in the flowing H2 and N2 gases. In some embodiments, H2 and N2 are provided to the reaction chamber before the plasma is ignited or nitrogen and hydrogen atoms or nitrogen and hydrogen radicals are formed. Without being bound to any theory, it is believed that hydrogen may have a beneficial effect in the ligand removal step (i.e., remove some of the remaining ligands) or may have other beneficial effects on the properties of the film. In some embodiments, H2 and N2 are continuously provided to the reaction chamber, and the plasma, nitrogen and hydrogen containing atoms or radicals are generated or provided when needed.

[0044] Typically, the second reactant, including, for example, nitrogen plasma, is provided for about 0.1 seconds to about 10 seconds. In some embodiments, the second reactant (such as nitrogen plasma) is provided for about 0.1 seconds to about 10 seconds, 0.5 seconds to about 5 seconds, or 0.5 seconds to about 2.0 seconds. However, depending on the type of reactor, substrate type and its surface area, the pulse time of the second reactant may even be greater than about 10 seconds. In some embodiments, the pulse time may be on the order of minutes. The optimal pulse time can be readily determined by one of skill in the art based on the particular circumstances.

[0045] In some embodiments, the second reactant is provided in two or more distinct pulses without introducing another reactant between any of the two or more pulses. For example, in some embodiments, the nitrogen plasma is provided in two or more, preferably two, sequential pulses without introducing the Si precursor between the sequential pulses. In some embodiments, two or more sequential pulses of plasma are generated before introducing or removing another precursor, such as the Si precursor, or purging, by providing a plasma discharge for a first time while providing the nitrogen plasma, stopping the plasma discharge for a second time (e.g., about 0.1 seconds to about 10 seconds, about 0.5 seconds to about 5 seconds, about 1.0 seconds to about 4.0 seconds), and turning it on again for a third time. Additional pulses of plasma may be introduced in the same direction. In some embodiments, the plasma is ignited at equal times in each of the pulses.

[0046] In some embodiments, the nitrogen plasma may be generated by applying an RF voltage of about 10 W to about 2000 W, preferably about 50 W to about 1000 W, and more preferably about 100 W to about 500 W. In some embodiments, the RF voltage density is about 0.02 W / cm. 2 ~ approx. 2.0 W / cm 2 , preferably about 0.05 W / cm 2 ~Approx. 1.5W / cm 2 The RF voltage may be applied to the nitrogen flowing during the nitrogen plasma pulse time, flowing continuously through the reaction chamber and / or flowing through a remote plasma generator. Thus, in some embodiments, the plasma is generated in situ, while in other embodiments, the plasma is generated remotely. In some embodiments, a showerhead reactor is used, and the plasma is generated between a susceptor (top portion on which the substrate is placed) and a showerhead plate. In some embodiments, the spacing between the susceptor and the showerhead plate is about 0.1 cm to about 20 cm, about 0.5 cm to about 5 cm, or about 0.8 cm to about 3.0 cm.

[0047] After a sufficient time for the nitrogen plasma pulse to flood and react with the pre-adsorbed molecular layer, any excess reactants and reaction by-products are removed from the reaction space. As with the removal of the first reactant, this step may include stopping the generation of the reactants and continuing to flow an inert gas (such as nitrogen or argon) for a period of time sufficient to allow the excess reactants and volatile reaction by-products to diffuse and be purged from the reaction space. In other embodiments, a separate purge gas may be used. In some embodiments, the purge may be from about 0.1 seconds to about 10 seconds, from about 0.1 seconds to about 4 seconds, from about 0.1 seconds to about 0.5 seconds. The simultaneous supply and removal of the nitrogen plasma represents a second reactant phase in the silicon nitride atomic layer deposition cycle.

[0048] Together, the second phase represents one ALD cycle that repeatedly forms a silicon nitride thin film of a desired thickness. While an ALD cycle is generally referred to herein as beginning with a silicon phase, it is contemplated that in other embodiments, the cycle may begin with a reactive species phase. Those skilled in the art will appreciate that the first precursor phase generally reacts with the tail left by the last phase in the previous cycle. Thus, if the reactive species phase is the first phase in the first ALD cycle, in a subsequent cycle, the reactive species phase will effectively follow the silicon phase, although no reactants were previously adsorbed on the substrate surface or present in the reaction space. In some embodiments, one or more distinct ALD cycles are provided in the deposition process.

[0049] According to some embodiments of the present invention, the PEALD reaction may be carried out at about 25° C. to about 700° C., preferably about 50° C. to about 600° C., more preferably about 100° C. to about 450° C., and most preferably about 200° C. to about 400° C. In some embodiments, the optimum reactor temperature may be limited by the maximum allowable heat balance. Thus, in some embodiments, the reaction temperature is about 300° C. to about 400° C. In some applications, the maximum temperature is around about 400° C., and therefore the PEALD process proceeds at that reaction temperature.

[0050] According to some embodiments of the present invention, the pressure in the reaction chamber during the process is maintained at about 0.01 torr to about 50 torr, preferably about 0.1 torr to about 10 torr.

[0051] (Si precursor) Several suitable silicon precursors may be used in the presently disclosed PEALD process. At least some suitable precursors may be of the general formula:

[0052] [ka] In the formula, n=1 to 10, y=1 or more (up to 2n+2-z), z=0 or more (up to 2n+2-y), X is I or Br, A is a halogen other than X, and n=1 to 5 is preferably, n=1 to 3 is more preferably, 1 to 2.

[0053] According to some embodiments, the silicon precursor may include one or more cyclic compounds. According to some embodiments, the silicon precursor may include one or more cyclic compounds. Such precursors may be of the general formula:

[0054] [ka] In the formula, the compound of chemical formula (2) is a cyclic compound, n=3 to 10, y=1 or more (up to 2n-z), z=0 or more (up to 2n-y), X is I or Br, A is a halogen other than X, and preferably n=3 to 6.

[0055] According to some embodiments, the silicon precursor may include one or more iodosilanes. Such precursors may have the general formula:

[0056] [ka] In the formula, n=1 to 10, y=1 or more (up to 2n+2-z), z=0 or more (up to 2n+2-y), A is a halogen other than I, preferably n=1 to 5, more preferably n=1 to 3, and most preferably 1 to 2.

[0057] According to some embodiments, some silicon precursors may include one or more cyclic iodosilanes. Such precursors may have the general formula:

[0058] [ka] In the formula, the compound of chemical formula (4) is a cyclic compound, n=3 to 10, y=1 or more (up to 2n-z), z=0 or more (up to 2n-y), A is a halogen other than I, and preferably n=3 to 6.

[0059] According to some embodiments, some silicon precursors may include one or more bromosilanes. Such precursors may have the following general formula:

[0060] [ka] In the formula, n=1 to 10, y=1 or more (up to 2n+2-z), z=0 or more (up to 2n+2-y), A is a halogen other than Br, preferably n=1 to 5, more preferably n=1 to 3, and most preferably 1 to 2.

[0061] According to some embodiments, some silicon precursors may include one or more cyclic bromosilanes. Such precursors may have the following general formula:

[0062] [ka] In the formula, the compound of chemical formula (6) is a cyclic compound, n=3 to 10, y=1 or more (up to 2n-z), z=0 or more (up to 2n-y), A is a halogen other than Br, and preferably n=3 to 6.

[0063] According to some embodiments, preferred silicon precursors include one or more iodosilanes. Such precursors may have the general formula:

[0064] [ka] In the formula, n=1 to 5, y=1 or more (up to 2n+2), preferably n=1 to 3, and more preferably n=1 to 2.

[0065] According to some embodiments, preferred silicon precursors include one or more bromosilanes. Such precursors may have the general formula:

[0066] [ka] In the formula, n=1 to 5, y=1 or more (up to 2n+2), preferably n=1 to 3, and more preferably n=1 to 2.

[0067] According to some PEALD process embodiments, suitable silicon precursors may include at least a compound having any one of the general formulas (1)-(8). In the general formulas (1)-(8), the halide / halogen may include F, Cl, Br, and I. In some embodiments, the silicon precursor includes SiI4, HSiI3, H2SiI2, H3SiI, Si2I6, HSi2I5, H2Si2I4, H3Si2I3, H4Si2I2, H5Si2I, or Si3I8. In some embodiments, the silicon precursor includes one of HSiI3, H2SiI2, H3SiI, H2Si2I4, H4Si2I2, and H5Si2I. In some embodiments, the silicon precursor comprises two, three, four, five or six of HSiI3, H2SiI2, H3SiI, H2Si2I4, H4Si2I2, and H5Si2I, and combinations thereof.

[0068] In one embodiment, the Si precursor is H2SiI2.

[0069] In some embodiments, Si precursors of the following formulas (9)-(28) may be used in the PEALD process.

[0070] (N precursor) As discussed above, the second reactant in the PEALD process of the present invention may include a nitrogen precursor, which may include reactive species. Suitable plasma compositions include nitrogen plasma, nitrogen radicals, or atomic nitrogen, in one form or another. Hydrogen plasma, hydrogen radicals, or atomic hydrogen are also provided, in one form or another. In some embodiments, the plasma may contain a noble gas (He, Ne, Ar, Kr, and Xe, preferably Ar or He) in plasma form, as radicals, or in atomic form. In some embodiments, the second reactant does not include any species from a noble gas (such as Ar). Thus, in some embodiments, the plasma is not generated in a gas containing a noble gas.

[0071] Thus, in some embodiments, the second reactant may include a plasma formed from a compound having both N and H (NH3 and N2H4, a mixture of N2 / H2, or other precursors having NH bonds). In some embodiments, the second reactant may be formed, at least in part, from N2. In some embodiments, the second reactant may be formed, at least in part, from N2 and H2, with N2 and H2 being provided at a flow ratio (N2 / H2) of about 20:1 to about 1:20, preferably about 10:1 to about 1:10, more preferably about 5:1 to about 1:5, and most preferably about 1:2 to about 4:1, and in some cases 1:1.

[0072] The second reactant may, in some embodiments, be formed remotely via a plasma discharge away from the substrate or reaction space (a "remote plasma"), while in some embodiments the second reactant may be generated directly near or above the substrate (a "direct plasma").

[0073] 3 is a flow chart generally illustrating a silicon nitride PEALD deposition cycle that may be used to deposit silicon nitride thin films of some embodiments. In certain embodiments, the silicon nitride thin films are formed on a substrate by a PEALD-type process that includes multiple silicon nitride deposition cycles, each silicon nitride deposition cycle 300 including: (1) contacting a substrate with a vaporized silicon precursor 310 such that the silicon compound adsorbs on the substrate surface; (2) introducing a nitrogen precursor into reaction space 320; (3) generating reactive species from a nitrogen precursor 330; and (4) contacting 340 the substrate with a reactive species, thereby converting the adsorbed silicon compound to silicon nitride;

[0074] Nitrogen may be flowed continuously throughout the cycle for an appropriate time with the nitrogen plasma being formed to convert the adsorbed silicon compounds to silicon nitride.

[0075] As noted above, in some embodiments, the substrate may be contacted with the silicon compound and the reactive species simultaneously, while in other embodiments, these reactants are provided separately.

[0076] The contacting step is repeated (350) until a film of the desired thickness and composition is obtained. Excess reactants may be purged from the reaction space after each contacting step (i.e., steps 310 and 340).

[0077] According to some embodiments, silicon nitride thin films are deposited using a PEALD process on substrates having three-dimensional features (such as using FinFETs). The PEALD process may include the following steps: (1) providing a substrate including a three-dimensional structure in a reaction space; (2) a silicon-containing precursor (such as SiI2H2) is introduced into the reaction space where the silicon-containing precursor is adsorbed onto the surface of the substrate; (3) excess silicon-containing precursor and reaction by-products are removed from the reaction space; (4) a nitrogen-containing precursor (such as N2, NH3, N2H4, or N2 and H2) is introduced into the reaction space; (5) generating reactive species from the nitrogen precursor; (6) contacting the substrate with a reactive species; and (7) Removing excess nitrogen atoms, plasma, or radicals and reaction by-products.

[0078] Steps (2) through (7) may be repeated until a silicon nitride film of the desired thickness is formed.

[0079] In some embodiments, steps (5) and (6) are replaced by steps in which nitrogen atoms, plasma or radicals are remotely formed and provided to the reaction space.

[0080] In some embodiments, the PEALD process is carried out at about 200°C to about 400°C, about 300°C to about 400°C, or at about 400°C.

[0081] (Thermal ALD process) The methods provided herein also enable the deposition of silicon nitride films on substrate surfaces by thermal ALD processes. Geometrically challenging applications such as three-dimensional structures are also possible with these thermal processes. According to some embodiments, thermal atomic layer deposition (ALD) type processes are used to form silicon nitride films on substrates such as integrated circuit workpieces.

[0082] The substrate or workpiece is placed in a reaction chamber and undergoes alternating self-limiting surface reactions. Preferably, to form a silicon nitride film, each thermal ALD cycle includes at least a two-dimensional phase. The provision and removal of reactants from the reaction space may be considered phases. In a first phase, a first reactant comprising silicon is provided on the substrate surface and forms no more than about one monolayer. This reactant may be referred to herein as a "silicon precursor" or "silicon reactant" and may be, for example, H2SiI2. In a second phase, a second reactant comprising a nitrogen-containing compound is provided and reacts with the adsorbed silicon precursor to form SiN. This second reactant may be referred to as a "nitrogen precursor" or "nitrogen reactant." The second reactant may include NH3 or another suitable nitrogen-containing compound. Additional phases may be added or removed as needed to adjust the composition of the final film.

[0083] One or more of the reactants may be provided using a carrier gas (such as Ar or He). In some embodiments, the silicon precursor and the nitrogen precursor are provided using a carrier gas.

[0084] In some embodiments, the two phases may overlap or be combined. For example, the silicon precursor and the nitrogen precursor may be provided simultaneously in partially or completely overlapping pulses. In addition, although referred to as first and second phases and first and second reactants, the order of phases and the order of reactant provision may vary, and an ALD cycle may begin with any one of the phases or reactants. That is, unless otherwise specified, the reactants may be provided in any order, and the process may begin with any reactant.

[0085] As described in more detail below, in some embodiments for depositing silicon nitride films, one or more deposition cycles begin with the provision of a silicon precursor, typically followed by a nitrogen precursor. In some embodiments, one or more deposition cycles begin with the provision of a nitrogen precursor, followed by a silicon precursor.

[0086] Again, one or more of the reactants may be provided using a carrier gas (such as Ar or He). In some embodiments, a nitrogen precursor is provided using a carrier gas. In some embodiments, although referred to as first and second phases and first and second reactants, the order of the phases, and therefore the order of reactant provision, may be altered, and an ALD cycle may begin with any one of the phases.

[0087] In some embodiments, the substrate (such as a semiconductor workpiece) on which deposition is desired is loaded into a reactor. The reactor may be part of a cluster 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 showerhead type of reactor is used. In some embodiments, a spatially separated type reactor is used. In some embodiments, a high capacity manufacturable single wafer ALD reactor is used. In other embodiments, a batch reactor containing multiple substrates is used. In embodiments where a batch ALD reactor is used, the number of substrates is preferably 10-200, more preferably 50-150, and most preferably 100-130. In other embodiments, a batch reactor containing multiple substrates is used. In embodiments where a batch ALD reactor is used, the number of substrates is preferably 10-200, more preferably 50-150, and most preferably 100-130.

[0088] Exemplary single-wafer reactors specifically designed for amplifying ALD processes are commercially available from ASM Americas, Inc. (Phoenix, AZ) under the trade names Pulsar® 2000 and Pulsar® 3000, and from ASM Japan, Inc. (Tokyo, JP) under the trade names Eagle® XP, XP8, and Dragon®. Exemplary batch ALD reactors specifically designed for amplifying ALD processes are commercially available from ASM Europe BV (Almere, NL) under the trade names A400™ and A412™. Exemplary batch ALD reactors specifically designed for amplifying ALD processes are commercially available from ASM Europe BV (Almere, NL) under the trade names A400™ and A412™.

[0089] In some embodiments, if necessary, the exposed surface of the workpiece is pretreated to provide reactive sites for reaction with the first phase of the ALD process. In some embodiments, a separate pretreatment step is not required. In some embodiments, the substrate is pretreated to provide a desired surface termination.

[0090] In some embodiments, excess reactants and reaction by-products, if any, are removed from near the precursors, such as the substrate surface, between reactant pulses. In some embodiments, excess reactants and reaction by-products are removed from the reaction chamber between reactant pulses, for example by purging with an inert gas. The flow rate and time of each reactant can be adjusted, and the purging step allows for control of the film properties and characteristics. In some embodiments, the step of removing excess reactants and / or reaction by-products includes moving the substrate.

[0091] The flow rates and times of each reactant are adjustable as the removal step allows for different properties and characteristics of the film.

[0092] As noted above, in some embodiments, the gas is provided to the reaction chamber continuously during each deposition cycle or the entire ALD process, while in other embodiments, the gas may be nitrogen, helium, or argon.

[0093] The ALD cycles are repeated until a film of the desired thickness and composition is obtained. In some embodiments, deposition parameters (flow rates, flow times, purge times, and / or the precursors themselves) may be altered in one or more deposition cycles during an ALD process to obtain a film with desired characteristics.

[0094] The term "pulse" may be understood to include providing a reactant to a reaction chamber for a predetermined period of time. The term "pulse" does not limit the length or duration of the pulse and can be of any length of time.

[0095] In some embodiments, the silicon reactant is provided first. If necessary or desired, after the initial surface termination, a first silicon reactant pulse is applied to the workpiece. According to some embodiments, the first reactant pulse includes a carrier gas flow and a volatile silicon species (such as H2SiI2) that is reactive with the workpiece surface of interest. Thus, the silicon reactant adsorbs onto the workpiece surface. The first reactant pulse self-saturates the workpiece surface such that excess components of the first reactant pulse do not substantially further react with the molecular layer formed in the process.

[0096] The first silicon reactant pulse is preferably provided in gaseous form. A silicon precursor gas is considered "volatile" for purposes of the present invention if the reactant species exhibits sufficient vapor pressure under process conditions to deliver the reactant species to the workpiece in sufficient concentration to fill exposed surfaces.

[0097] In some embodiments, the silicon reactant pulse is from about 0.05 seconds to about 5.0 seconds, from about 0.1 seconds to about 3 seconds, from about 0.2 seconds to about 1.0 seconds. In a batch process, the silicon precursor pulse can be substantially as long as can be determined by one of skill in the art given the particular circumstances.

[0098] After a sufficient time for a molecular layer to adsorb onto the substrate surface, the excess first precursor is then removed from the reaction space, hi some embodiments, the excess first precursor is purged by stopping the flow of the first precursor and continuing to flow a carrier gas or purge gas for a sufficient time to diffuse or purge excess reactants and reactant by-products, if any, from the reaction space.

[0099] In some embodiments, the first precursor is purged for about 0.1 seconds to about 10 seconds, about 0.3 seconds to about 5 seconds, about 0.3 seconds to about 1 second. The provision and removal of the silicon precursor may be considered the first or silicon phase of an ALD cycle. In a batch process, the purging of the first precursor may be determined by one of skill in the art given the specific circumstances.

[0100] A second nitrogen precursor is pulsed into the reaction space and contacts the substrate surface. The nitrogen precursor may be provided using a carrier gas. The nitrogen precursor may be, for example, NH3 or N2H4. The nitrogen precursor pulse is preferably provided in gaseous form. A nitrogen precursor is considered "volatile" for purposes of this description if the reactive species exhibits sufficient vapor pressure up to process conditions to transport the reactive species to the workpiece in sufficient concentration to fill the exposed surface.

[0101] In some embodiments, the nitrogen precursor pulse is from about 0.05 seconds to about 5.0 seconds, 0.1 seconds to about 3.0 seconds, or from about 0.2 seconds to about 1.0 seconds. In batch processes, the nitrogen precursor pulse is substantially longer than would be measurable by one of skill in the art given the particular circumstances.

[0102] After sufficient time for the molecular layer to adsorb to the substrate surface with available binding sites, the second nitrogen precursor is removed from the reaction space. In some embodiments, the flow of the second nitrogen precursor is stopped and the carrier gas is continued for a sufficient time to diffuse or purge excess reactants and reaction by-products, if any, from the reaction space, preferably from a reaction space greater than about two reaction chamber volumes of purge gas, and even more preferably from a reaction space greater than about three reaction chamber volumes. The supply and removal of the nitrogen precursor may be considered the second or nitrogen phase of an ALD cycle.

[0103] In some embodiments, the nitrogen precursor is purged for about 0.1 seconds to about 10.0 seconds, about 0.3 seconds to about 5.0 seconds, or about 0.3 seconds to about 1.0 seconds. In a batch process the first precursor purge can be substantially longer than would be determined by one of skill in the art given the particular circumstances.

[0104] The nitrogen phase removal or purging step and the flow rate and time of the nitrogen precursor pulses can be adjusted to achieve the desired composition in the silicon nitride film. Because the adsorption of nitrogen precursors to the substrate surface is typically self-limiting, due to a limited number of binding sites, the pulse parameters can be adjusted so that less than a monolayer of nitrogen is adsorbed in one or more cycles.

[0105] The two phases together represent one ALD cycle, which is repeated to form a silicon nitride thin film of a desired thickness. Although the ALD cycle is generally referred to herein as beginning with the silicon phase, it is contemplated that in other embodiments, the cycle may begin with the nitrogen phase. Those skilled in the art will appreciate that the first precursor phase generally reacts with the terminations left over from the last layer in the previous cycle. In some embodiments, one or more different ALD cycles are provided in the deposition process.

[0106] According to some embodiments of the present invention, the ALD reaction may be carried out at a temperature of about 25° C. to about 1000° C., preferably about 100° C. to about 800° C., more preferably about 200° C. to about 650° C., and most preferably about 300° C. to about 500° C. In some embodiments, the optimum reactor temperature may be limited by the maximum allowable heat balance. Thus, the reaction temperature may be about 300° C. to about 400° C. In some applications, the maximum temperature is about 400° C. or so, and the process therefore proceeds at that reaction temperature.

[0107] (Si precursor) Some suitable silicon precursors may be used in the presently disclosed thermal processes (such as thermal ALD processes). In some embodiments, these precursors may be used in plasma ALD processes to deposit films with desired properties (desired WER, WERR, pattern loading effect, and / or step coverage, at least one of the mechanisms described below).

[0108] According to some embodiments, some silicon precursors include iodine, and films deposited using the precursors have at least one desired property (e.g., a desired WER, WERR, pattern loading effect, or / and step coverage, at least one of the mechanisms described below).

[0109] According to some embodiments, some silicon precursors include bromine, and films deposited using the precursors have at least one desired property (e.g., a desired WER, WERR, pattern loading effect, or / and step coverage, at least one of the mechanisms described below).

[0110] At least some suitable precursors may be of the general formula:

[0111] [ka] wherein n=1-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=0 or more (up to 2n+2-yz), X is I or Br, A is a halogen other than X, R is an organic ligand, and is independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, most preferably 1-2. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl, or isopropyl).

[0112] According to some embodiments, some silicon precursors include one or more cyclic compounds. Such precursors may be of the general formula:

[0113] [ka] wherein n=3-10, y=1 or more (up to 2n-zw), z=0 or more (up to 2n-yw), w=0 or more (up to 2n-yz), X is I or Br, A is a halogen other than X, R is an organic ligand independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine and unsaturated hydrocarbon, preferably n=3-6, and preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl or isopropyl).

[0114] According to some embodiments, some silicon precursors include one or more iodosilanes. Such precursors may have the general formula:

[0115] [ka] wherein n=1-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=0 or more (up to 2n+2-yz), A is a halogen other than I, R is an organic ligand and is independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, most preferably 1-2. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl or isopropyl).

[0116] According to some embodiments, some silicon precursors include one or more cyclic iodosilanes. Such precursors may have the general formula:

[0117] [ka] where n=3-10, y=1 or more (up to 2n-zw), z=0 or more (up to 2n-yw), w=0 or more (up to 2n-yz), A is a halogen other than I, R is an organic ligand, and is independently selected from the group consisting of alkoxides, alkylsilyls, alkyls, substituted alkyls, alkylamines, and unsaturated hydrocarbons, preferably n=3-6. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl, or isopropyl).

[0118] According to some embodiments, some silicon precursors include one or more bromosilanes. Such precursors may have the general formula:

[0119] [ka] wherein n=1-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=0 or more (up to 2n+2-yz), A is a halogen other than Br, R is an organic ligand and is independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, most preferably 1-2. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl or isopropyl).

[0120] According to some embodiments, some silicon precursors include one or more cyclic bromosilanes. Such precursors may have the general formula:

[0121] [ka] where n=3-10, y=1 or more (up to 2n-zw), z=0 or more (up to 2n-yw), w=0 or more (up to 2n-yz), A is a halogen other than Br, R is an organic ligand, and is independently selected from the group consisting of alkoxides, alkylsilyls, alkyls, substituted alkyls, alkylamines, and unsaturated hydrocarbons, preferably n=3-6. Preferably R is a C1-C3 alkyl ligand (methyl, ethyl, n-propyl, or isopropyl).

[0122] According to some embodiments, some silicon precursors include one or more iodosilanes or bromosilanes in which iodine or bromine is not bonded to silicon in the compound.Thus, some suitable compounds may include iodine / bromine substituted alkyl groups.Such precursors may have the following general formula:

[0123] [ka] In the formula, n=1 to 10, y=0 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=1 or more (up to n+2-yz), X is I or Br, A is a halogen other than X, R II are organic ligands containing I or Br, independently selected from the group consisting of alkoxides, alkylsilyls, alkyls, alkylamines, and unsaturated hydrocarbons substituted with I or Br, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably, R II teeth 、 It is an iodine-substituted C1-C3 alkyl ligand.

[0124] According to some embodiments, some silicon precursors include one or more cyclic iodosilanes or bromosilanes. Thus, some suitable cyclic compounds may have iodine / bromine substituted alkyl groups. Such precursors may have the following general formula:

[0125] [ka] In the formula, n=3 to 10, y=0 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=1 or more (up to n+2-yz), X is I or Br, A is a halogen other than X, and R II is an organic ligand containing I or Br, independently selected from the group consisting of alkoxides, alkylsilyls, alkyls, alkylamines, and unsaturated hydrocarbons substituted with I or Br, preferably n=3 to 6. Preferably, R is a C1 to C3 alkyl ligand substituted with iodine.

[0126] According to some embodiments, some suitable silicon precursors may have at least one of the following general formulas:

[0127] [ka] In the formula, n=1-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=1 or more (up to n+2-yz), X is I or Br, A is a halogen other than X, N is nitrogen, R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, most preferably 1-2. Preferably, R1 and R2 are hydrogen or C1-C4 alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl). More preferably, R1 and R2 are hydrogen or C1-C3 alkyl groups (such as methyl, ethyl, n-propyl or isopropyl). (NR1R2) w The ligands may each be selected independently of the other.

[0128] [ka] where y=1 or more (up to 3-zw), z=0 or more (up to 3-yw), w=1 or more (up to 3-yz), X is I or B, A is a halogen other than X, N is nitrogen, R1 and R2 may be independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon. Preferably, R1 and R2 are hydrogen or C1-C4 alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R1 and R2 are hydrogen or C1-C3 alkyl groups (such as methyl, ethyl, n-propyl, or isopropyl). (NR1R2) w Each of the ligands may be selected independently from the others. 3-y-z-w X y A z (NR1R2) w The Si ligands may be selected independently from each other.

[0129] In some embodiments, some suitable precursors may have at least one of the following more specific chemical formulas:

[0130] [ka] wherein n=1-10, y=1 or more (up to 2n+2-w), w=1 or more (up to 2n+2-y), N is nitrogen, and R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably, R1 and R2 are hydrogen or C1-C4 alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R1 and R2 are hydrogen or C1-C3 alkyl groups (such as methyl, ethyl, n-propyl, or isopropyl). (NR1R2) w Each of the ligands may be selected independently from the others.

[0131] [ka] where y=1 or more (up to 3-w), w=1 or more (up to 3-y), N is nitrogen, and R1 and R2 may be independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon. Preferably, R1 and R2 are hydrogen or C1-C4 alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl), more preferably, R1 and R2 are hydrogen or C1-C3 alkyl groups (such as methyl, ethyl, n-propyl, or isopropyl). Three H 3-y-w I y (NR1R2) w Each of the Si ligands may be selected independently of the others.

[0132] According to some embodiments, some suitable silicon precursors may have at least one of the following general formulas:

[0133] [ka] In the formula, n=1-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=1 or more (up to n+2-yz), X is I or Br, A is a halogen other than X, N is nitrogen, R1 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, and R2 is independently selected from the group consisting of alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably, R1 is hydrogen or a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R1 is hydrogen or a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). Preferably, R2 is a C1-C4 alkyl group (methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl. (NR1R2) w Each of the ligands may be selected independently from the others.

[0134] [ka] In the formula, y=1 or more (up to 3-zw), z=0 or more (up to 3-yw), w=1 or more (up to 3-yz), X is I or Br, A is a halogen other than X, N is nitrogen, R1 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, R2 is independently selected from the group consisting of alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably, R1 is hydrogen or a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R1 is hydrogen or a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). Preferably, R2 is a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl. More preferably, R2 is a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). (NR1R2) w Each of the ligands may be selected independently from the others.

[0135] In some embodiments, some suitable precursors may have at least one of the following more specific chemical formulas:

[0136] [ka] In the formula, n=1-10, y=1 or more (up to 2n+2-w), w=1 or more (up to 2n+2-y), N is nitrogen, R1 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, and R2 is independently selected from the group consisting of alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably, R1 is hydrogen or a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R1 is hydrogen or a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). Preferably, R2 is a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably, R2 is a C1 to C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). (NR1R2) w Each of the ligands may be selected independently from the others.

[0137] [ka] Wherein y=1 or more (up to 3-w), w=1 or more (up to 3-y), N is nitrogen, R1 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, R2 is independently selected from the group consisting of alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, preferably n=1-5, more preferably n=1-3, and most preferably 1-2. Preferably R1 is hydrogen or a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl). More preferably R1 is hydrogen or a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). Preferably, R2 is a C1-C4 alkyl group (such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl. More preferably, R2 is a C1-C3 alkyl group (such as methyl, ethyl, n-propyl, or isopropyl). (NR1R2) w Each of the ligands may be selected independently from the others.

[0138] According to some embodiments of a thermal ALD process, a suitable silicon precursor may include at least a compound having any one of the general formulas (9)-(24). In general formulas (9)-(18) and general formulas (21) and (22), the halide / halogen may include F, Cl, Br, and I.

[0139] In some embodiments, the silicon precursor comprises one or more of the following: SiI4, HSiI3, H2SiI2, H3SiI, Si2I6, HSi2I5, H2Si2I4, H3Si2I3, H4Si2I2, H5Si2I, Si3I8, HSi2I5, H2Si2I4, H3Si2I3, H4Si2I2, H5Si2I, MeSiI3, Me2SiI2, Me3SiI, MeSi2I5, Me2Si2I4, Me3Si2I3, Me4Si2I2, Me5Si2I, HMeSiI2, HMe2SiI, HMeSi2I4, HMe2Si2I3, HMe3Si2I2, HMe4Si2 I, H2MeSiI, H2MeSi2I3, H2Me2Si2I2, H2Me3Si2I, H3MeSi2I2, H3Me2Si2I, H4MeSi2I, EtSiI3, Et2SiI2, Et3SiI, EtSi2I5, Et2Si2I4, Et3Si2I3, Et4Si2I2, Et5 Si2I, HEtSiI2, HEt2SiI, HEtSi2I4, HEt2Si2I3, HEt3Si2I2, HEt4Si2I, H2EtSiI, H2EtSi2I3, H2Et2Si2I2, H2Et3Si2I, H3EtSi2I2, H3Et2Si2I, and H4EtSi2I.

[0140] In some embodiments, the silicon precursor comprises one or more of the following: EtMeSiI 2、 Et2MeSiI, EtMe2SiI, EtMeSi2I4, Et2MeSi2I3, EtMe2Si2I3, Et3MeSi2I2, Et2Me2Si2I2, EtMe3Si2I2, Et4MeSi2I, Et3Me2Si2I, Et2Me3Si2I, EtMe4Si2I , HEtMeSiI, HEtMeSi2I3, HEt2MeSi2I2, HEtMe2Si2I2, HEt3MeSi2I, HEt2Me2Si2I, HEtMe3Si2I, H2EtMeSi2I2, H2Et2MeSi2I, H2EtMe2Si2I, H3EtMeSi2I.

[0141] In some embodiments, the silicon precursor comprises one or more of the following: HSiI3, H2SiI2, H3SiI, H2Si2I4, H4Si2I2, H5Si2I, MeSiI3, Me2SiI2, Me3SiI, Me2Si2I4, Me4Si2I2, HMeSiI2, H2Me2Si2I2, EtSiI3, Et2SiI2, Et3SiI, Et2Si2I4, Et4Si2I2, and HEtSiI2. In some embodiments, the silicon precursor comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or more compounds selected from HSiI3, H2SiI2, H3SiI, H2Si2I4, H4Si2I2, H5Si2I, MeSiI3, Me2SiI2, Me3SiI, Me2Si2I4, Me4Si2I2, HMeSiI2, H2Me2Si2I2, EtSiI3, Et2SiI2, Et3SiI, Et2Si2I4, Et4Si2I2, and HEtSiI2 and any combination thereof. In some embodiments, the silicon precursor is H2SiI2.

[0142] In some embodiments, the silicon precursor comprises three iodines bonded to silicon and one amine or alkylamine ligand. In some embodiments, the silicon precursor comprises one or more of the following: (SiI3)NH2, (SiI3)NHMe, (SiI3)NHEt, (SiI3)NH i Pr, (SiI3)NH t Bu, (SiI3)NMe2, (SiI3)NMeEt, (SiI3)NMe i Pr, (SiI3)NMe t Bu, (SiI3)NEt2, (SiI3)NEt i Pr, (SiI3)NEt t Bu, (SiI3)N i Pr2, (SiI3)N i Pr t Bu, and (SiI3)N t Bu2. In some embodiments, the silicon precursor comprises one or more of the following: (SiI3)NH2, (SiI3)NHMe, (SiI3)NHEt, (SiI3)NH iPr, (SiI3)NH t Bu, (SiI3)NMe2, (SiI3)NMeEt, (SiI3)NMe i Pr, (SiI3)NMe t Bu, (SiI3)NEt2, (SiI3)NEt i Pr, (SiI3)NEt t Bu, (SiI3)N i Pr2, (SiI3)N i Pr t Bu, and (SiI3)N t In some embodiments, the silicon precursor is (SiI3)NH2, (SiI3)NHMe, (SiI3)NHEt, (SiI3)NH i Pr, (SiI3)NH t Bu, (SiI3)NMe2, (SiI3)NMeEt, (SiI3)NMe i Pr, (SiI3)NMe t Bu, (SiI3)NEt2, (SiI3)NEt i Pr, (SiI3)NEt t Bu, (SiI3)N i Pr2, (SiI3)N i Pr t Bu, (SiI3)N t In some embodiments, the silicon precursor comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more compounds selected from the group consisting of (SiI2)(NH2)2, (SiI2)(NHMe)2, (SiI2)(NHEt)2, (SiI2)(NH i Pr)2, (SiI2)(NHtBu)2, (SiI2)(NMe2)2, (SiI2)(NMeEt)2, (SiI2)(NMe i Pr)2, (SiI2)(NMe t Bu)2, (SiI2)(NEt2)2, (SiI2)(NEt i Pr)2, (SiI2)(NEt tBu)2, (SiI2)(N i Pr2)2, (SiI2)(N i Pr t Bu)2, and (SiI2)(N t In some embodiments, the silicon precursor is (SiI)(NH), (SiI)(NHMe), (SiI)(NHEt), (SiI)(NH i Pr)2, (SiI2)(NH t Bu)2, (SiI2)(NMe2)2, (SiI2)(NMeEt)2, (SiI2)(NMe i Pr)2, (SiI2)(NMe t Bu)2, (SiI2)(NEt2)2, (SiI2)(NEt i Pr)2, (SiI2)(NEt t Bu)2, (SiI2)(N i Pr2)2, (SiI2)(N i Pr t Bu)2, (SiI2)(N t Bu), and combinations thereof.

[0143] In some embodiments, the silicon precursor comprises two iodines, one hydrogen, and one amine or alkylamine ligand bonded to silicon. In some embodiments, the silicon precursor comprises one or more of the following: (SiI2H)NH2, (SiI2H)NHMe, (SiI2H)NHEt, (SiI2H)NH i Pr, (SiIH)NH t Bu, (SiI2H)NMe2, (SiI2H)NMeEt, (SiI2H)NMe i Pr, (SiIH)NMe t Bu, (SiI2H)NEt2, (SiI2H)NEt i Pr, (SiIH)NEt t Bu, (SiIH)N i Pr2, (SiI2H)N i Pr t Bu, and (SiIH)N tIn some embodiments, the silicon precursor is (SiI2H)NH2, (SiI2H)NHMe, (SiI2H)NHEt, (SiI2H)NH i Pr, (SiIH)NH t Bu, (SiI2H)NMe2, (SiI2H)NMeEt, (SiI2H)NMe i Pr, (SiIH)NMe t Bu, (SiI2H)NEt2, (SiI2H)NEt i Pr, (SiIH)NEt t Bu, (SiIH)N i Pr2, (SiI2H)N i Pr t Bu, (SiIH)N t Bu2, and combinations thereof.

[0144] In some embodiments, the silicon precursor comprises one iodine, one hydrogen, and two amine or alkylamine ligands bonded to silicon. In some embodiments, the silicon precursor comprises one or more of the following: (SiIH)(NH2)2, (SiIH)(NHMe)2, (SiIH)(NHEt)2, (SiIH)(NH i Pr)2, (SiIH)(NH t Bu)2, (SiIH)(NMe2)2, (SiIH)(NMeEt)2, (SiIH)(NMe i Pr)2, (SiIH)(NMe t Bu)2, (SiIH)(NEt2)2, (SiIH)(NEt i Pr)2, (SiIH)(NEt t Bu)2, (SiIH)(N i Pr2)2, (SiIH)(N i Pr t Bu)2, and (SiIH)(N t In some embodiments, the silicon precursor is (SiIH)(NH), (SiIH)(NHMe), (SiIH)(NHEt), (SiIH)(NH i Pr)2, (SiIH)(NHt Bu)2, (SiIH)(NMe2)2, (SiIH)(NMeEt)2, (SiIH)(NMe i Pr)2, (SiIH)(NMe t Bu)2, (SiIH)(NEt2)2, (SiIH)(NEt i Pr)2, (SiIH)(NEt t Bu)2, (SiIH)(N i Pr2)2, (SiIH)(N i Pr t Bu)2, and (SiIH)(N t Bu), and combinations thereof.

[0145] In some embodiments, the silicon precursor comprises one iodine, two hydrogens, and one amine or alkylamine ligand bonded to silicon. In some embodiments, the silicon precursor comprises one or more of the following: (SiIH2)NH2, (SiIH2)NHMe, (SiIH2)NHEt, (SiIH2)NH i Pr, (SiIH2)NH t Bu, (SiIH2)NMe2, (SiIH2)NMeEt, (SiIH2)NMe i Pr, (SiIH2)NMe t Bu, (SiIH2)NEt2, (SiIH2)NEt i Pr, (SiIH2)NEt t Bu, (SiIH2)N i Pr2, (SiIH2)N i Pr t Bu, and (SiIH2)N t In some embodiments, the silicon precursor is (SiIH2)NH2, (SiIH2)NHMe, (SiIH2)NHEt, (SiIH2)NH i Pr, (SiIH2)NH t Bu, (SiIH2)NMe2, (SiIH2)NMeEt, (SiIH2)NMeiPr, (SiIH2)NMe t Bu, (SiIH2)NEt2, (SiIH2)NEt iPr, (SiIH2)NEt t Bu, (SiIH2)N i Pr2, (SiIH2)N i Pr t Bu, (SiIH2)N t Bu2, and combinations thereof.

[0146] In some embodiments, the silicon precursor comprises one iodine, three amine ligands, or alkylamine ligands bonded to silicon. In some embodiments, the silicon precursor comprises one or more of the following: (SiI)(NH2)3, (SiI)(NHMe)3, (SiI)(NHEt)3, (SiI)(NH i (Pr)3, (SiI)(NH t Bu)3, (SiI)(NMe2)3, (SiI)(NMeEt)3, (SiI)(NMe i (Pr)3, (SiI)(NMe t Bu)3, (SiI)(NEt2)3, (SiI)(NEt i (Pr)3, (SiI)(NEt t Bu)3, (SiI)(N i Pr2)3, (SiI)(N i Pr t Bu)3, and (SiI)(N t In some embodiments, the silicon precursor is (SiI)(NH2)3, (SiI)(NHMe)3, (SiI)(NHEt)3, (SiI)(NH i (Pr)3, (SiI)(NH t Bu)3, (SiI)(NMe2)3, (SiI)(NMeEt)3, (SiI)(NMe i (Pr)3, (SiI)(NMe t Bu)3, (SiI)(NEt2)3, (SiI)(NEt i (Pr)3, (SiI)(NEt t Bu)3, (SiI)(N i Pr2)3, (SiI)(N i Pr t Bu)3, (SiI)(N tBu)3, and combinations thereof.

[0147] In some embodiments, the silicon precursor comprises two iodines bonded to silicon, hydrogen and one amine or alkylamine ligand or two iodines and two alkylamine ligands, where the amine or alkylamine ligand is selected from amine NH2-, methylamine MeNH-, dimethylamine Me2N-, ethylmethylamine EtMeN-, ethylamine EtNH-, and diethylamine Et2N-. In some embodiments, the silicon precursor comprises one or more of the following: (SiI2H)NH2, (SiI2H)NHMe, (SiI2H)NHEt, (SiI2H)NMe2, (SiI2H)NMeEt, (SiI2H)NEt2, (SiI2)(NH2), (SiI2)(NHMe)2, (SiI2)(NHEt)2, (SiI2)(NMe2), (SiI2)(NMeEt)2, and (SiI2)(NEt2). In some embodiments, the silicon precursor comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or more compounds selected from (SiI2H)NH2, (SiI2H)NHMe, (SiI2H)NHEt, (SiI2H)NMe2, (SiI2H)NMeEt, (SiI2H)NEt2, (SiI2)(NH2)2, (SiI2)(NHMe)2, (SiI2)(NHEt)2, (SiI2)(NMe2)2, (SiI2)(NMeEt)2, (SiI2)(NEt2)2, and combinations thereof.

[0148] (Other Si precursor types containing I or Br) Some suitable silicon precursors containing nitrogen (such as iodine or bromine substituted silazanes) or some suitable silicon precursors containing sulfur can be used in the presently disclosed thermal and plasma ALD processes. In some embodiments, some suitable silicon precursors containing nitrogen (such as iodine or bromine substituted silazanes) can be used in the presently disclosed thermal and plasma ALD processes to deposit films having desired properties (e.g., at least one of the desired WER, WERR, pattern loading effect, or / and step coverage of the mechanisms described below).

[0149] At least some suitable iodine or bromine substituted silicon precursors may have the following general formula:

[0150] [ka] where n=2-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=0 or more (up to 2n+2-yz), X is I or Br, E is N or S, preferably N, A is a halogen other than X, R is an organic ligand independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine and unsaturated hydrocarbon, preferably n=2-5 and more preferably n=2-3, most preferably 1-2. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl or isopropyl).

[0151] At least some suitable iodine or bromine substituted silazane precursors may have the following general formula:

[0152] [ka] where n=2-10, y=1 or more (up to 2n+2-zw), z=0 or more (up to 2n+2-yw), w=0 or more (up to 2n+2-yz), X is I or Br, A is a halogen other than X, R is an organic ligand independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine and unsaturated hydrocarbon, preferably n=2-5 and more preferably n=2-3, most preferably 2. Preferably R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl or isopropyl).

[0153] In some embodiments, the silicon precursor comprises a Si compound containing I or Br, such as a heterocyclic Si compound. Such cyclic precursors may include the following substructures:

[0154] [ka] In the formula, E is N or S, preferably N.

[0155] In some embodiments, the silicon precursor comprises a substructure according to formula (27), and examples of this type of compound are, for example, iodine or bromine substituted cyclosilazanes, such as iodine or bromine substituted cyclotrisilazanes.

[0156] In some embodiments, the silicon precursor comprises a Si compound (silylamine-based compound) containing I or Br. Such silylamine-based Si precursors may have the general formula:

[0157] [ka] where y=1 or more (up to 3-zw), z=0 or more (up to 3-yw), w=0 or more (up to 3-yz), X is I or Br, A is a halogen other than X, and R is an organic ligand, which may be independently selected from the group consisting of alkoxide, alkylsilyl, alkyl, substituted alkyl, alkylamine, and unsaturated hydrocarbon. Preferably, R is a C1-C3 alkyl ligand (such as methyl, ethyl, n-propyl, or isopropyl). Three H 3-y-z-w X y A z R w Each of the Si ligands may be independently selected from one another.

[0158] (N precursor) According to some embodiments, the second reactant or nitrogen precursor in a thermal ALD process can be NH, NH, or a number of other suitable nitrogen compounds having NH bonds.

[0159] 4 is a flow chart generally illustrating a silicon nitride thermal ALD deposition cycle that can be used to deposit silicon nitride thin films of some embodiments. In certain embodiments, a silicon nitride thin film is formed on a substrate by an ALD-type process that includes multiple silicon nitride deposition cycles, each silicon nitride deposition cycle 400 including: (1) contacting a substrate with a vaporized silicon precursor 410 such that the silicon compound adsorbs on the substrate surface; (2) removing excess silicon reactant and any by-products 420; (3) contacting the substrate with a nitrogen precursor 430; and (4) removing excess nitrogen precursor and reaction by-products 440;

[0160] The contacting step is repeated 450 times until a thin film of the desired thickness and composition is obtained. As noted above, in some embodiments, the substrate may be contacted with the silicon compound and the nitrogen precursor simultaneously, while in other embodiments, these reactants may be provided separately.

[0161] According to some embodiments, silicon nitride thin films are deposited using a thermal ALD process on substrates having three-dimensional features (such as for use with FinFETs). The process may include the following steps, although they are not required to be performed in the following order: (1) a substrate to be filled into the reaction space; (2) A silicon-containing precursor (such as HSiI) is introduced into the reaction space such that the silicon-containing precursor is adsorbed on the surface of the substrate; (3) The step of removing excess silicon-containing precursor and reaction by-products is carried out, for example by purging. (4) A nitrogen-containing precursor (such as NH3 or N2H4) is introduced into the reaction space and reacts with the silicon-containing precursor on the substrate; (5) removing excess nitrogen-containing precursor and reaction by-products, such as by purging; and (6) Steps (2) through (5) may be repeated until a silicon nitride film of the desired thickness is formed.

[0162] In some embodiments, the ALD process is carried out at a temperature between about 100° C. and about 800° C., between about 200° C. and about 600° C., or between about 300° C. and about 500° C. In some applications, the reaction temperature is about 400° C.

[0163] (Characteristics of SiF film) Silicon nitride thin films deposited by some of the embodiments discussed herein (regardless of whether the silicon precursor contains bromine or iodine) may achieve impurity levels or concentrations of less than about 3 at-%, preferably less than about 1 at-%, more preferably less than about 0.5 at-%, and most preferably less than about 0.1 at-%. In some films, total impurity levels, excluding hydrogen, may be less than about 5 at-%, preferably less than about 2 at-%, more preferably less than about 1 at-%, and most preferably less than about 0.2 at-%. And in some films, hydrogen levels may be less than about 30 at-%, preferably less than about 20 at-%, more preferably less than about 15 at-%, and most preferably less than about 10 at-%.

[0164] In some embodiments, the deposited SiN film does not contain a significant amount of carbon. However, in some embodiments, a SiN film containing carbon is deposited. For example, in some embodiments, an ALD reaction is performed using a silicon precursor containing carbon to deposit a thin silicon nitride film containing carbon. In some embodiments, a SiN film containing carbon is deposited using a precursor containing an alkyl group or other carbon-containing ligand. In some embodiments, a silicon precursor of one of formulas (9)-(28) and a silicon precursor containing an alkyl group are used in a PEALD or thermal ALD process as described above to deposit a SiN film containing carbon. Different alkyl groups or other carbon-containing ligands may produce different carbon concentrations in the film due to different reaction mechanisms. Thus, different precursors can be selected to produce different carbon concentrations in the deposited SiN film. In some embodiments, a thin SiN film containing carbon may be used, for example, as a low-k spacer. In some embodiments, the thin film does not contain argon.

[0165] Figures 5A-5B show FESEM images of various silicon nitride thin films deposited according to the invention. After the films were deposited, they were HF dipped for 2 minutes. Figures 6A-6C show the same silicon nitride films after a dHF drip process. Uniform etching can be seen.

[0166] According to some embodiments, silicon nitride thin films may exhibit step coverage and pattern loading effects of greater than about 50%, preferably greater than about 80%, more preferably greater than about 90%, and most preferably greater than about 95%. In some cases, step coverage and pattern loading effects can be greater than about 98% and in some cases about 100% (within the accuracy of the measurement means or method). These values ​​can be achieved with aspect ratios greater than 2, preferably greater than 3, more preferably greater than 5, and most preferably greater than 8.

[0167] As used herein, "pattern loading effect" is used according to its ordinary meaning in the art. When used herein to refer to film thickness variations in the substrate area where the structure is present, pattern loading effect may be expressed in terms of impurity content, density, electrical properties, and etch rate, unless otherwise indicated by the term pattern loading effect. Thus, pattern loading effect may be given as the film thickness at the sidewall or bottom of a feature within a three-dimensional structure / feature relative to the film thickness of the three-dimensional structure facing the broad field. As used herein, a pattern loading effect of 100% (or a percentage of 1) would represent nearly perfectly uniform film properties across the substrate, regardless of the feature (i.e., in other words, would indicate no pattern loading effect (variation in a particular film property (e.g., thickness) in a feature versus the broad field)).

[0168] In some embodiments, the silicon nitride film is deposited to a thickness of about 3 nm to about 50 nm, preferably about 5 nm to about 30 nm, more preferably about 5 nm to about 20 nm. These thicknesses can be achieved in feature sizes (widths) of less than about 100 nm, preferably less than about 50 nm, more preferably less than about 30 nm, most preferably less than about 20 nm, and in some cases less than about 15 nm. According to some embodiments, the SiN film is deposited on a three-dimensional structure, and the sidewalls may be uniform in thickness to slightly more than 10 nm.

[0169] According to some embodiments, silicon nitride films with various wet etching rates (WER) can be deposited. When using a blanket WER in 0.5% dHF (nm / min), the silicon nitride films can have a WER value of less than about 5, preferably less than about 4, more preferably less than about 2, and most preferably less than about 1. In some embodiments, the WER value can be less than about 0.3.

[0170] The WER over the entire surface in 0.5% dHF (nm / min) relative to the WER of thermal oxide may be less than about 3, preferably less than about 2, more preferably less than about 1, and most preferably less than about 0.5.

[0171] And, in some embodiments, the sidewall WER of a three-dimensional feature (such as a vane or groove) relative to the WER of the top surface may be less than about 4, preferably less than about 3, more preferably less than about 2, and most preferably about 1.

[0172] In using the silicon nitride thin films of the present invention, it has been found that due to the improved film properties and etching characteristics, the difference in top and sidewall thickness may not be critical in some applications. Nevertheless, in some embodiments, the thickness gradient along the sidewall may be crucial to subsequent applications or processes.

[0173] In some embodiments, the etching amount of the silicon nitride films of the present invention may be less than about 1 or 2 times the etching observed for thermal SiO2 (TOX) in a 0.5% HF-dip process (e.g., less than 1 or 2 times the SiN improvement when deposited according to the methods disclosed herein in a process where about 2 to about 3 nm of TOX is removed). The WER of the preferred silicon nitride films may be less than the WER of prior art thermal oxide films.

[0174] (Specific circumstances regarding the use of SiN film) The methods and materials described herein can provide films with improved properties, and improved etching characteristics can provide improved SiN films for use in traditional lateral transistor designs with horizontal source / drain (S / D) and gate surfaces, as well as non-horizontal (e.g., vertical) surfaces and complex three-dimensional (3D) structures. In some embodiments, SiN films are deposited by the disclosed methods on three-dimensional structures during integrated circuit fabrication. Three-dimensional transistors may include, for example, double-gate field effect transistors (DG FETs) and other types of multi-gate FETs, including FinFETs. For example, the silicon nitride thin films of the present invention may be useful in non-planar multi-gate transistors (such as FinFETs), where it may be desirable to form silicide on the vertical walls in addition to the tops of the gate, source, and drain regions.

[0175] Another three-dimensional structure for which the SiN deposition techniques taught herein are particularly useful is the three-dimensional advanced source / drain structure taught by Shifren et al. in U.S. Patent Application Publication No. 2009 / 0315120(A1), the disclosure of which is incorporated herein by reference in its entirety. Shifren et al. teach advanced source / drain structures that include vertical sidewalls. EXAMPLES

[0176] Example 1 Silicon nitride thin films were deposited at 400°C as described herein by a PEALD process using H2SiI2 as the silane precursor and H2+N2 plasma as the nitrogen precursor. The films exhibited a combination of some of the best qualities from both ALD reaction types: typical high quality from the PEALD SiN films, and isotropic etch behavior from the thermal ALD films. Although these results are not fully understood, the film properties and etch behavior were nevertheless within the specifications for high quality spacer layer applications.

[0177] In this application, the step coverage and pattern loading effect in the trench structure with aspect ratio 2 should be more than 95%, the wet etching rate (WER) should be less than 50% of the WER of thermal silicon oxide (SiO2, TOX), and the etching rate should be approximately the same on the horizontal and vertical walls of the trench structure. Therefore, the growth rate should be more than 0.5 nm / min, and the impurity content should be as low as possible.

[0178] The film growth rate at 400 °C was 0.52 Å / cycle with a thickness non-uniformity of 6.2% (1-σ). The refractive index was 2.04 with a non-uniformity of 0.7% (1-σ). The growth rate per minute was not yet optimized and was 0.13 nm / min.

[0179] The wet etch rate of the planar film was 1.13 nm / min, which is 46.7% of the WER of Tox (2.43 nm / min). In the trench structures, the conformality of the film was about 91.0-93.1% and the pattern loading effect was about 95.7-99.3% as deposited (before etching). After 2 min of dilute (0.5%) HF etching, the conformality values ​​were about 91.5-94.6% and the pattern loading effect was about 97.4-99.5%. The wet etch rate on the top surface of the trench was 4.32 nm / min (A), 2.98 nm / min on the trench sidewalls (B), and 3.03 nm / min on the trench bottom (C). The field region showed an etch rate of 2.63 nm / min (D).

[0180] Without being bound to any particular theory, it is believed that an iodine or bromine ligand removal step is advantageously performed prior to the plasma discharge to avoid residual ligands decomposing and re-entering the film as impurities, and in the case of halides, to avoid the formation of plasma activated halides.

[0181] The composition of the silicon nitride thin film deposited according to the present invention was analyzed by HFS-RBS. The results are shown in Table 1 below. Additionally, XRR data was obtained from the same film. The thickness of the film was measured to be about 117 nm. The mass density was 2.63 (±0.1) g / cm. 3 And the RMS roughness of the surface was measured to be 1.76 (±0.1) nm.

[0182] [Table 1]

[0183] Example 2 Silicon nitride thin films with improved etching properties and impurity content (compared to Example 1) were deposited by the PEALD process of the present invention in a direct current plasma ALD showerhead reactor. Susceptor temperatures of 200°C and 400°C were used. H2SiI2 was used as the silicon precursor and H2+N2 plasma was used as the nitrogen precursor. The plasma power was about 200W to about 220W, and the space between the showerhead plate and the susceptor (i.e., the space where the plasma is generated) was 10mm. The plasma did not contain Ar. Nitrogen was used as the carrier gas and flowed throughout the deposition process. H2SiI2 consumption was about 9.0mg / cycle.

[0184] At 400 °C, the film growth rate was 0.7 Å / cycle and the deposited films were conformal. The refractive index ranged from 1.92 to 1.93. The wet etch rate (WER) of the planar films in 100:1 dHF was about 20-30% of the WER of thermal oxide (SiO2). In trench structures, the ratio of the wet etch rate of the film on the trench sidewall to the top of the trench varied from about 0.8 to about 1.0.

[0185] The impurity content of silicon nitride thin films deposited at 200° C. was analyzed by TXRF. The films had slightly less impurity content (1.418×10) than the films deposited using a plasma containing Ar in addition to the H+N plasma. 13 Iodine atoms / cm 2) which is 8.43 × 10 12 Iodine atoms / cm 2 In addition, the film deposited at 400 °C using Ar-containing plasma contained Ar (8.067 × 10 13 Argon atoms / cm 2 Without being bound to any particular theory, it is believed that argon is trapped inside the film and using an argon-free plasma may avoid impurity inclusion.

[0186] It will be understood by those skilled in the art that many and various modifications may be made without departing from the spirit of the present invention. The disclosed features, structures, properties, and precursors may be combined in any suitable manner. Therefore, it should be clearly understood that the forms of the present invention are illustrative only and are not intended to limit the scope of the present invention. All modifications and changes are intended to be included within the scope of the present invention, which is defined by the appended claims.

Claims

1. 1. A plasma-enhanced atomic layer deposition (PEALD) method for depositing a silicon nitride thin film on a substrate in a reaction space, the method having a plurality of deposition cycles, at least one of the plurality of deposition cycles comprising: (a) introducing into said reaction space a gas phase silicon reactant comprising silicon, iodine and hydrogen; (b) flowing a purge gas through the reaction space and using the purge gas to remove excess silicon reactant and reaction by-products from the reaction space; (c) flowing a nitrogen-containing precursor including N 2 gas and H 2 gas into the reaction space, generating a plasma in the N 2 gas and the H 2 gas to generate reactive species, and contacting the substrate with the reactive species; (d) flowing a purge gas through the reaction space to remove excess reactants and reaction by-products from the reaction space; Including, the reaction space has a susceptor and a showerhead plate, and the distance between the susceptor and the showerhead plate is in the range of 0.5 cm to 5 cm; The reactive species is in the nitrogen-containing precursor and has a density of 0.02 W / cm between the susceptor and the showerhead plate. ２ 2.0W / cm or more ２ The plasma is generated by applying an RF voltage having an RF voltage density in the range: the silicon reactant is consumed at a rate of 0.1 mg to 50 mg per deposition cycle; and The method, wherein the substrate is a 300 mm wafer.

2. The method of claim 1 , wherein nitrogen is continuously flowed into the reaction space throughout the deposition cycle.

3. The RF voltage density is 0.05 W / cm ２ 1.5W / cm or more ２ 2. The method of claim 1, wherein the range is:

4. 10. The method of claim 1, wherein the silicon reactant is consumed at a rate of 2 mg to 20 mg per deposition cycle.

5. The silicon reactants include precursors having the general formula: H ２ｎ＋２－ｙ－ｚ－ｗ Si ｎ I ｙ A ｚ R ｗ 2. The method of claim 1, wherein n=1-10, y=1 or more (up to 2n+2-z-w), z=0 or more (up to 2n+2-y-w), w=0 or more (up to 2n+2-y-z), A is a halogen other than I, and R is an organic ligand independently selected from the group consisting of alkoxides, alkylsilyls, alkyls, substituted alkyls, alkylamines, and unsaturated hydrocarbons.

6. The silicon reactant is (SiI ２ H) NHMe, (SiI ２ H) NHEt, (SiI ２ H) NMe ２ , (SiI ２ H) NMeEt, (SiI ２ H) NEt ２ , (SiI ２ ) (NHMe) ２ , (SiI ２ ) (NHEt) ２ , (SiI ２ )(NMe ２ ) ２ , (SiI ２ ) (NMeEt) ２ , (SiI ２ ) (NEt ２ ) ２ The method of claim 1 , comprising a precursor having the general formula:

7. The silicon reactant is H ２ SiI ２ The method of claim 1 , comprising:

8. 10. The method of claim 1, wherein the spacing between the susceptor and the showerhead plate is in the range of 0.8 cm to 3.0 cm.

9. The method of claim 1, carried out at a temperature of 200°C to 400°C.

10. The method of claim 1 , wherein the silicon nitride thin film is formed on a three-dimensional structure.

11. 11. The method of claim 10, wherein the silicon nitride thin film exhibits at least 80% step coverage and pattern loading effect.

12. 11. The method of claim 10, wherein an etching rate of the silicon nitride thin film on a sidewall of the three-dimensional structure with 0.5% aqueous HF is less than 2% compared to an etching rate of the silicon nitride thin film on a top surface of the three-dimensional structure with 0.5% aqueous HF.

13. 2. The method of claim 1, wherein the silicon nitride thin film has an etch rate of less than 4 nm / min with 0.5% aqueous HF.

14. The method of claim 1 , wherein the purge gas in step (b) comprises nitrogen.

15. The method of claim 1 , wherein the purge gas in step (d) comprises nitrogen.

16. The method of claim 1 , wherein the substrate does not come into contact with reactive species generated by a plasma of Ar.

17. 10. The method of claim 1, further comprising generating a plasma in the nitrogen-containing precursor for a first period of time to generate the reactive species, ceasing to discharge the plasma for a second period of time, and generating a plasma in the nitrogen-containing precursor for a third period of time.

18. A plasma enhanced atomic layer deposition (PEALD) method for forming silicon nitride thin films, the method comprising a plurality of cycles, each cycle comprising alternating and sequentially contacting a 300 mm wafer in a reaction space with gas phase pulses of a silicon reactant and a second reactant comprising a reactive species produced by generating a plasma in a nitrogen-containing precursor comprising N2 gas and H2 gas; wherein the silicon reactant comprises silicon, iodine and hydrogen; the reaction space has a susceptor and a showerhead plate, and the distance between the susceptor and the showerhead plate is in the range of 0.5 cm to 5 cm; The plasma was 0.02 W / cm between the susceptor and the showerhead plate in the nitrogen-containing precursor. ２ 2.0W / cm or more ２ The plasma is generated by applying an RF voltage having an RF voltage density in the range: The method wherein the silicon reactant is consumed at a rate of 0.1 mg to 50 mg per deposition cycle.

19. 1. A method for depositing a silicon nitride thin film on a substrate in a reaction space having a susceptor and a showerhead plate by a plasma-enhanced atomic layer deposition (PEALD) process, the method comprising performing a plurality of deposition cycles, at least one of the plurality of deposition cycles comprising: (a) introducing into said reaction space a gas phase silicon reactant comprising silicon, iodine and hydrogen; (b) removing excess silicon reactant and reaction by-products from the reaction space with a purge gas; (c) flowing reactant gases including N2 gas and H2 gas into the reaction space, generating a plasma in the N2 gas and the H2 gas to generate reactive species, and contacting the substrate with the reactive species above the substrate and between the susceptor and the showerhead plate; (d) removing excess plasma and reaction by-products from the reaction space with a purge gas; Including, wherein the distance between the susceptor and the showerhead plate is in the range of 0.5 cm to 5 cm; The plasma is irradiated to the reactant gas between the susceptor and the showerhead plate at a power of 0.02 W / cm ２ 2.0W / cm or more ２ This is generated by applying an RF voltage having an RF voltage density in the range: A method wherein the reactant gas is flowed continuously into the reaction space throughout the deposition cycle.

20. The RF voltage density is 0.05 W / cm ２ 1.5W / cm or more ２ 20. The method of claim 19, wherein the range is:

21. The silicon reactant is H ２ SiI ２ 20. The method of claim 19, comprising:

22. The method of claim 19 , wherein the reactant gas acts as the purge gas.

23. The N ２ and H ２ 20. The method of claim 19, wherein the gas is flowed continuously throughout the deposition cycle.

24. The method of claim 19 , wherein the reactant gas further comprises a noble gas.

25. 20. The method of claim 19, wherein the spacing between the susceptor and the showerhead plate is in the range of 0.8 cm to 3.0 cm.

26. 20. The method of claim 19, wherein the silicon nitride thin film is formed on a three-dimensional structure.

27. 27. The method of claim 26, wherein the silicon nitride thin film exhibits at least 80% step coverage and pattern loading effect.

28. 27. The method of claim 26, wherein an etch rate of the silicon nitride thin film on a sidewall of the three-dimensional structure with 0.5% aqueous HF is less than 2% compared to an etch rate of the silicon nitride thin film on a top surface of the three-dimensional structure with 0.5% aqueous HF.

29. 20. The method of claim 19, wherein the silicon nitride thin film has an etch rate in 0.5% aqueous HF of less than 4 nm / min.

30. 20. The method of claim 19, wherein the substrate does not come into contact with reactive species generated by a plasma of Ar.

31. 20. The method of claim 19, further comprising generating a plasma discharge in the reactant gas for a first period of time to generate the reactive species, terminating the plasma discharge for a second period of time, and generating the plasma discharge in the reactant gas for a third period of time.

32. A plasma enhanced atomic layer deposition (PEALD) method for forming a silicon nitride thin film, the method comprising a plurality of cycles, each cycle comprising alternating and sequentially contacting a substrate in a reaction space with gas phase pulses of a silicon reactant and a second reactant comprising a reactive species produced by generating a plasma in a gas comprising N2 gas and H2 gas; wherein the silicon reactant comprises silicon, iodine and hydrogen; the reaction space has a susceptor and a showerhead plate, and the distance between the susceptor and the showerhead plate is in the range of 0.5 cm to 5 cm; The plasma has a density of 0.02 W / cm between the susceptor and the showerhead plate. ２ 2.0W / cm or more ２ The RF voltage having an RF voltage density in the following range is applied to the gas containing N 2 gas and H 2 gas, The method wherein said gases including N 2 and H 2 gases are flowed continuously throughout said cycle.

33. The N ２ Gas and H ２ 33. The method of claim 32, wherein the gas comprising gas further comprises a noble gas.

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