CN116745461A

CN116745461A - Conformal and smooth titanium nitride layer and method of forming same

Info

Publication number: CN116745461A
Application number: CN202180083129.1A
Authority: CN
Inventors: 赵贤哲; 金海英; 阿吉特·达赫姆汗; 本森·B·尼; 郑昇勋
Original assignee: Eugene Nass Co ltd
Current assignee: Eugene Nass Co ltd
Priority date: 2020-12-10
Filing date: 2021-12-09
Publication date: 2023-09-12
Also published as: WO2022125820A1; EP4259845A1; KR20230125798A; JP2023552983A; TW202240006A

Abstract

The disclosed technology relates generally to forming thin films comprising titanium nitride (TiN), and more particularly to forming thin films comprising (TiN) by a periodic vapor deposition process. In one aspect, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposure to a Ti precursor at a Ti precursor flow and exposure to an N precursor at an N precursor flow, wherein a ratio of the N precursor flow to the Ti precursor flow exceeds 3. The method is such that the TiN film has a preferential (111) crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4. Aspects also relate to semiconductor structures including the films and methods of forming the same.

Description

Conformal and smooth titanium nitride layer and method of forming same

Incorporation by reference of any priority application

Any and all applications of the foreign or domestic priority claims identified in the application data sheet filed with the present application in accordance with 37cfr 1.57 are hereby incorporated by reference.

The present application is a partial continuation of U.S. application Ser. No. 16/595,945 entitled "conformal and smooth titanium nitride layer and method of forming it (CONFORMAL AND SMOOTH TITANIUM NITRIDE LAYERS AND METHODS OF FORMING THE SAME)" filed on 10.2019, and the contents of each of which are hereby expressly incorporated by reference in their entirety, in accordance with 35U.S. C. ≡119 (e) claiming priority from U.S. provisional patent application Ser. No. 63/123,733 entitled "conformal and smooth titanium nitride layer and method of forming it (CONFORMAL AND SMOOTH TITANIUM NITRIDE LAYERS AND METHODS OF FORMING THE SAME)" filed on 12.10.2020.

Background

Technical Field

The disclosed technology relates generally to forming titanium nitride layers, and more particularly to conformal and smooth titanium nitride layers.

Background

Titanium nitride (TiN) has been widely used in the fabrication of various structures in Integrated Circuits (ICs). For example, tiN has been used for diffusion barriers, various electrodes, and metallization structures. This widespread use of TiN in IC fabrication is attributable to its structural, thermal and electrical properties. As the dimensions of various IC structures shrink, tiN is formed on features with smaller and smaller dimensions and complex topologies. For example, as technology nodes scale to 10nm nodes and even smaller, there is a need for TiN layers (e.g., as diffusion barriers) that can conformally line high aspect ratio trenches and vias having dimensions as small as a few nanometers. Although techniques such as Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) have been used in the IC industry for decades to form TiN, the increased demand for the conformality of TiN films to be deposited in smaller trenches or vias may ultimately limit their use. On the other hand, while Atomic Layer Deposition (ALD) has proven useful for conformal deposition of TiN films, some electrical properties (e.g., conductivity) and physical properties (e.g., surface roughness) of the films may be inferior compared to TiN films formed using other methods such as Physical Vapor Deposition (PVD). Accordingly, there is a need for an atomic layer deposition method for forming TiN-based films for use in IC fabrication that have superior surface smoothness and step coverage relative to TiN films formed by PVD and CVD, while also having matching or superior electrical and physical properties.

Disclosure of Invention

In one aspect, a method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a first portion of the thin film on a semiconductor substrate by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposure to a first Ti precursor and exposure to a first N precursor. Further, the method includes forming a second portion of the thin film on the first portion of the thin film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor and exposing to a second N precursor. The exposure to one or both of the Ti precursor and the N precursor during the one or more second ALD cycles is at a higher pressure relative to the corresponding exposure to one or both of the Ti precursor and the N precursor during the one or more first ALD cycles.

In another aspect, a method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process includes providing a semiconductor substrate comprising trenches or vias having an aspect ratio exceeding 1. Further, the method includes forming the thin film in the trench or the via by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each including exposing to a first Ti precursor and exposing to a first N precursor to form a first portion of the thin film in the trench or the via. Furthermore, the method includes exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor and exposing to a second N precursor to form a second portion of the thin film on the first portion of the thin film. The exposure to one or both of the first Ti precursor and the first N precursor during the one or more first periodic vapor deposition cycles is at a different pressure than the corresponding exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles.

In another aspect, a semiconductor structure includes a semiconductor substrate including a non-metallic sidewall surface in a trench or via having an aspect ratio exceeding 5. Further, the semiconductor structure includes a thin film comprising TiN conformally coating the non-metallic sidewall surface, wherein a ratio of a thickness of the thin film formed on a lower 25% of a height of the trench or the via to an upper 25% of the height of the trench or the via exceeds 0.9.

In another aspect, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposing to a Ti precursor at a Ti precursor flow and exposing to an N precursor at an N precursor flow, wherein a ratio of the N precursor flow to the Ti precursor flow exceeds 3. The method is such that the TiN film has a preferential (111) crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4.

In another aspect, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposing to a Ti precursor at a Ti precursor flow and exposing to an N precursor at an N precursor flow, wherein the N precursor flow exceeds 500sccm. The method is such that the TiN film has a preferential (111) crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4.

In another aspect, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposing to a Ti precursor at a Ti precursor flow and exposing to an N precursor at an N precursor flow. Further, the method includes forming a second TiN film on the TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow. The method is such that one or both of the TiN film and the second TiN film has a preferential (111) crystal texture such that an X-ray spectrum of the one or both of the TiN film and the second TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4.

In another aspect, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a first TiN film on a semiconductor substrate at a first pressure by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposing to a first Ti precursor at a first Ti precursor flow and exposing to a first N precursor at a first N precursor flow. The first TiN film has a crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN exceeding 0.4. Further, the method includes forming a second TiN film on the first TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow at a second pressure higher than the first pressure.

In another aspect, a semiconductor structure includes a semiconductor substrate including a non-metallic sidewall surface in a trench or via having an aspect ratio exceeding 5. Further, the semiconductor structure includes a thin film comprising TiN conformally coating the non-metallic sidewall surface, wherein the thin film has a crystalline texture such that an X-ray diffraction spectrum of the thin film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystalline orientation to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystalline orientation of more than 0.4.

In another aspect, a semiconductor structure includes a semiconductor substrate including a non-metallic sidewall surface in a trench or via having an aspect ratio exceeding 5. Further, the semiconductor structure includes a thin film comprising TiN conformally coating the non-metallic sidewall surface, wherein the thin film comprises a lower portion and an upper portion, wherein the lower portion and the upper portion have different crystal textures. At least the lower portion of the film has a crystalline texture such that an X-ray diffraction spectrum of the film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to (111) crystalline orientation to a peak height or intensity of an X-ray diffraction peak corresponding to (200) crystalline orientation of more than 0.4.

Drawings

FIGS. 1A-1D schematically illustrate nucleation and growth mechanisms of thin films in different growth modes.

Fig. 2 is a cross-sectional transmission electron micrograph of a TiN layer grown by thermal atomic layer deposition on an oxide coated silicon substrate.

Fig. 3A is a flow chart schematically illustrating an atomic layer deposition method of forming a TiN layer by exposing a substrate to multiple cycles of different corresponding precursor exposure pressures, in accordance with an embodiment.

Fig. 3B schematically illustrates a cross-sectional view of a semiconductor structure including a TiN layer formed by an atomic layer deposition method in which a substrate is exposed to multiple cycles of different corresponding precursor exposure pressures, in accordance with an embodiment.

Fig. 4 schematically illustrates pressure traces for different cycles of an atomic layer deposition method in which a substrate is exposed to multiple cycles having different corresponding precursor exposure pressures, in accordance with an embodiment.

Fig. 5 schematically illustrates a cross-sectional view of a via lined with TiN layers having different thicknesses at different portions of the via.

Fig. 6 is a graph showing experimentally measured surface roughness and step coverage trend of TiN layers formed by an atomic layer deposition method in which a substrate is exposed to multiple cycles with different corresponding precursor exposure pressures, according to an embodiment, as a function of thickness.

Fig. 7A is a cross-sectional transmission electron micrograph of a high aspect ratio via lined with a TiN layer formed by an atomic layer deposition method in which the substrate is exposed to an ALD cycle performed at the same precursor exposure pressure.

Fig. 7B is a cross-sectional transmission electron micrograph of an upper region of the high aspect ratio via shown in fig. 7A.

Fig. 7C is a cross-sectional transmission electron micrograph of a lower region of the high aspect ratio via shown in fig. 7A.

Fig. 8A is a cross-sectional transmission electron micrograph of a TiN layer formed at an upper region of a high aspect ratio via similar to the high aspect ratio via shown in fig. 7A by a multiple cycle atomic layer deposition method in which the substrate is exposed to different corresponding precursor exposure pressures, according to an embodiment.

Fig. 8B is a cross-sectional transmission electron micrograph of a TiN layer formed at the lower region of the high aspect ratio via trench shown in fig. 8A.

Fig. 9 is a graph showing a statistical comparison of measured step coverage between TiN layers formed by atomic layer deposition at a single exposure pressure and TiN layers formed by atomic layer deposition at multiple exposure pressures, according to an embodiment.

Fig. 10 schematically illustrates a cross-sectional view of a TiN layer lined via formed by an atomic layer deposition method in which a substrate is exposed to multiple cycles of different corresponding precursor exposure pressures, in accordance with an embodiment.

Fig. 11 is a flow chart schematically illustrating an atomic layer deposition method of forming a TiN layer with high (111) crystalline texture by exposing a substrate to a relatively high N precursor flow, in accordance with an embodiment.

Fig. 12A illustrates experimental X-ray diffraction spectra of TiN films with varying degrees of (111) crystal texture according to an embodiment.

Fig. 12B is a graph illustrating an experimental ratio of the peak height of an X-ray diffraction peak corresponding to the (111) crystal orientation of TiN to the peak height of an X-ray diffraction peak corresponding to the (200) crystal orientation of TiN obtained from the X-ray diffraction spectrum of fig. 12A.

Fig. 13 is a graph of experimental thickness and resistivity measurements of TiN films with increased (111) crystalline texture according to an embodiment.

Fig. 14 is a graph of experimental hardness and modulus measurements for TiN films with increased (111) crystalline texture according to an embodiment.

Fig. 15 is a graph of experimental hardness measurements of TiN films with increased (111) crystalline texture according to an embodiment.

Fig. 16 illustrates experimental X-ray diffraction spectra of TiN films formed at different exposure pressures and having increased (111) crystal texture, according to an embodiment.

Fig. 17 illustrates a chlorine concentration depth profile of a TiN film with increased (111) crystal texture according to an embodiment.

Detailed Description

As described above, there is a need in the Integrated Circuit (IC) industry for smooth and conformal TiN films with superior electrical and physical properties, and methods of forming such films. To address these and other needs, disclosed herein are smooth and conformal thin films comprising TiN, and periodic vapor deposition methods of forming the thin films, which exhibit the conformal properties of films deposited by periodic vapor deposition processes, while also having electrical and physical properties that are superior or match those of TiN films formed by existing Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) methods. In particular, a method of forming a thin film comprising titanium nitride (TiN) includes forming a first portion of the thin film on a semiconductor substrate by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each including exposure to a first Ti precursor and exposure to a first N precursor. Further, the method includes forming a second portion of the thin film on the first portion of the thin film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor and exposing to a second N precursor. One or both of the second Ti precursor and the second N precursor are different during the one or more second periodic vapor deposition cycles than are correspondingly exposed to one or both of the first Ti precursor and the first N precursor during the one or more first periodic vapor deposition cycles. The periodic vapor deposition process disclosed herein is sometimes referred to as Atomic Layer Deposition (ALD). However, the periodic vapor deposition process is not limited to an atomic layer deposition process. For example, in various embodiments described herein, the precursor may saturate the reaction surface portion or substantially.

By exposing the substrate to the Ti and/or N precursors at a relatively low pressure (e.g., less than 3 torr) during deposition of the first portion of the thin film, the initial film growth may proceed substantially in a layer-by-layer growth mode, which advantageously results in lower average grain size and surface roughness relative to comparable TiN films deposited by exposing the substrate to the Ti and/or N precursors at a higher pressure (e.g., greater than 3 torr or 5 torr). On the other hand, by exposing the substrate to the Ti and/or N precursor at a relatively high pressure (e.g., greater than 3 torr) during deposition of the second portion of the thin film, the latter portion of the film growth advantageously results in higher conformality or step coverage relative to comparable TiN films deposited by exposing the substrate to the Ti and/or N precursor at a relatively low pressure (e.g., less than 3 torr or less than 1 torr).

In addition, because the first portion of the TiN film is grown in a layer-by-layer mode, the second portion of the film can be grown in a layer-by-layer mode using the first portion as a template, as compared to a comparable film grown starting with exposure to Ti and/or N precursors at a relatively higher pressure.

As a final result, when deposited on a particular surface (e.g., a surface comprising a non-metallic surface), the thin film comprising the first and second portions deposited by deposition according to the methods disclosed herein at two different corresponding exposure pressures for one or both of the Ti precursor and the N precursor advantageously has a combination of surface roughness and conformality that is superior to thin film layers formed on the same surface using a single pressure. Alternatively or in addition, due in part to the improved smoothness and conformality, the thin films have relatively low resistivity compared to TiN layers formed by some existing methods.

As described herein, unless explicitly limited, reference to a compound by its constituent elements that does not have its particular stoichiometric ratio should be understood to encompass all possible non-zero concentrations of each element. For example, titanium nitride (TiN) is understood to cover a material which may be represented by the general formula Ti _x All possible stoichiometric and non-stoichiometric compositions of N-expressed titanium nitride, where x>0, including TiN, ti ₃ N ₄ 、Ti ₄ N ₃ 、Ti ₆ N ₅ 、Ti ₂ N and TiN ₂ And other non-stoichiometric compositions of Ti and N.

As described above, titanium nitride (TiN) plays an important role in Integrated Circuit (IC) fabrication. Although techniques such as Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) have been used in the IC industry to deposit TiN, there has been an increasing demand for deposition methods for forming TiN-based films with high conformality without significantly compromising electrical and physical properties.

In addition, while plasma enhanced processes such as plasma enhanced atomic layer deposition (PE-ALD) may be effective in forming conformal films on surfaces having relatively low aspect ratios, such processes may not be effective in depositing films inside vias and cavities having relatively high aspect ratios. Without being bound by theory, one possible reason for this is that in some circumstances the plasma or its active species may not reach the deeper portions of the high aspect ratio vias. In these circumstances, different portions of the via may be exposed to different amounts of plasma or its reactive species, resulting in undesirable structural effects of non-uniform deposition, such as thicker film deposition near the opening of the via as compared to deeper portions (sometimes referred to as tapering or keyhole formation). For these reasons, thermal ALD may be more advantageous because thermal ALD is not dependent on the ability of a plasma or its active species to reach portions of the surface on which it is deposited.

However, while thermal ALD techniques may be suitable for forming relatively conformal TiN films on topography, particularly topography having a relatively high aspect ratio (e.g., greater than 1:1), the inventors have recognized that TiN films formed by thermal ALD may not be as good in some aspects (e.g., film roughness and resistivity) as TiN films formed by PVD or CVD. In this regard, the inventors have found that some of the electrical and/or physical properties of ALD grown TiN-based films can be affected by the growth mode. In particular, the inventors have found that while it may be desirable to grow TiN-based films in a two-dimensional layer-by-layer growth mode in ALD, such a layer-by-layer growth mode may not be readily achievable in some circumstances. The inventors have further found that growing TiN-based films by ALD in a layer-by-layer growth mode presents particular challenges in IC fabrication, wherein TiN-based films are formed on non-metallic surfaces such as insulating surfaces (such as oxide and nitride surfaces) or semiconductor surfaces (such as doped and undoped silicon surfaces). The inventors have recognized that the extent to which TiN-based films can be grown in a layer-by-layer growth mode can in turn depend on the initial growth mode, which depends on the type of surface, as described herein with reference to fig. 1A-1D, without being bound by any theory.

Fig. 1A schematically illustrates nucleation of a TiN layer and fig. 1B-1D illustrate different growth modes of the TiN layer on different surfaces. Referring to fig. 1A, once the precursor molecules 104 reach the surface of the substrate 100, they are physically adsorbed on the surface. Some of the adsorbed molecules 104 may diffuse along the surface of the substrate 100 until they reach an energetically favorable location to be chemisorbed. The surface diffusion is governed by, among other things, the substrate temperature, the substrate material, and the kinetic energy of the adsorbed molecules. When the size of the nuclei formed by chemisorbed molecules exceeds a certain size (sometimes referred to as a "critical size") determined by the tradeoff between the volumetric free energy and the surface energy, the nuclei may become energetically stable and begin to grow in size. The so-formed layer 108 of stabilized nuclei continues to grow by incorporating additional precursor molecules 104. Subsequent film growth may be categorized according to the different growth modes schematically illustrated in fig. 1B-1D.

Fig. 1B schematically illustrates a three-dimensional island growth pattern (sometimes referred to as Volmer-Weber growth pattern) that results in the formation of a layer 112 of three-dimensional islands. Without being bound by any theory, the island growth mode may predominate when the net surface free energy associated with the three-dimensional islands is positive, indicating that the deposited atoms are more strongly bound to each other than to the substrate. It will be appreciated that the energetics of ALD growth of TiN layers may favor island growth patterns, for example, when TiN metal layers are deposited on some semiconductor and/or insulating material surfaces.

Fig. 1C illustrates a layer-by-layer growth pattern (sometimes referred to as Frank-van der Merwe growth pattern) that results in the formation of a relatively smooth two-dimensional layer 116. Without being bound by any theory, the layer-by-layer growth mode may predominate when the deposited atoms are more strongly bound to the substrate than to each other, such that it is energetically favorable to stabilize the two-dimensional layer 116. The layer-by-layer growth mode can be maintained when the bonding energy between the layers continuously decreases from the bulk crystal value of the first monolayer to the TiN layer.

Although fig. 1B and 1C are two different possible growth modes of the thin film, it will be appreciated that in some circumstances, a growth mode intermediate between a layer-by-layer growth mode and a three-dimensional growth mode is possible. FIG. 1D illustrates an example of an intermediate growth mode known as the Stranski-Krastanov (SK) growth mode. Without being bound by any theory, SK growth may occur in film growth starting in a layer-by-layer mode. When layer-by-layer growth becomes detrimental after formation of one or more monolayers, the island growth mode begins to dominate over the layer-by-layer growth mode, resulting in a thin film structure 120 in which three-dimensional islands are formed on a two-dimensional initial layer. The SK growth mode may occur as a strain relaxation mechanism (strain-induced roughening).

In addition to interactions between the deposit and the substrate, other factors such as substrate temperature, reactor pressure, and deposition rate can significantly affect the nucleation and early growth processes, which in turn affect the final nanostructure or microstructure of the resulting film. For example, deposition conditions that enhance surface diffusion (e.g., relatively high substrate temperature, relatively low pressure, and/or low deposition rate) may promote growth in a layer-by-layer mode. Thus, initial film growth according to embodiments may proceed substantially in a layer-by-layer growth mode by enhancing surface diffusion during deposition of an initial portion of the TiN film, for example, by virtue of reduced pressure and growth rate, as disclosed herein.

It was found that when TiN is grown by ALD on various surfaces of interest in IC fabrication, such as dielectric and semiconductor surfaces, ALD growth is initialized in a three-dimensional island growth mode or SK growth mode. For example, in some circumstances, the silicon oxide layer is formed of Si, siO, both doped and undoped ₂ 、Si ₃ N ₄ ALD growth of TiN on the substrate surface of other high-K or low-K materials may proceed in either an island growth mode or an SK growth mode. The inventors have found that the subsequent growth of TiN by ALD generally results in undesirable film morphology for various applications of ultra-thin conformal TiN for high aspect ratio structures, due in part to the initial growth mode of either the island growth mode or the SK growth mode, as illustrated in fig. 2.

Fig. 2 is a cross-sectional transmission electron micrograph of a TiN layer grown by thermal ALD on a Si substrate coated with native oxide. After an initial film grown in three-dimensional island or SK growth mode, ALD growth of TiN is typically characterized by competing growth of adjacent crystals with different orientations, which in some circumstances results in V-shaped grains close to the nucleation layer and eventually forming columnar morphology at higher film thickness. As illustrated in fig. 2, the resulting film morphology includes faceted tops of posts that cause significant surface roughness and post boundaries with a lower density relative to the grains. It will be appreciated that the column boundaries may have significantly worse diffusion barrier properties relative to the grains themselves and may serve as a path of least resistance for transporting unwanted contaminants through the TiN layer.

The inventors have found that when an initial portion of a TiN layer is formed on a non-metallic surface by exposing a substrate to Ti and/or N precursors at relatively low pressure (e.g., less than 1 torr), an initial three-dimensional or SK growth mode may be suppressed and a layer-by-layer growth mode may be facilitated in an initial stage of TiN deposition (e.g., a nucleation stage). This may be because, among other reasons, localized diffusion of adsorbed Ti and N precursor molecules has more time to locally diffuse and wet the substrate surface (especially non-metallic surfaces) with a relatively low contact angle. TiN layers grown at relatively low exposure pressures result in layers that uniformly cover large areas of non-metallic surfaces without substantial island formation, making the initial growth phase more conducive to a layer-by-layer growth pattern on the substrate surface where ALD TiN will generally be favored for three-dimensional island or SK growth patterns as described above. Thus, by initiating ALD of TiN by exposing the substrate to Ti and/or N precursors at relatively low precursor exposure pressures (e.g., less than 3 torr), the resulting initial layer may be grown in a layer-by-layer mode (e.g., in a nucleation stage). Subsequent bulk growth phases, which may proceed by exposing the substrate to Ti and/or N precursors at relatively high precursor exposure pressures (e.g., greater than 3 torr), may continue to proceed in a layer-by-layer mode. By employing the method according to embodiments, some of the disadvantages of conventional ALD of TiN may be avoided, particularly in the case of certain semiconductor and/or insulating materials (including, in particular, si, siO ₂ And/or Si ₃ N ₄ An inorganic layer) directly on the TiN layer, this can be generally associated with an initial growth characterized by island-like or SK growth patterns followed by columnar growth as described above.

Fig. 3A is a flow chart schematically illustrating an atomic layer deposition method 300 of forming a TiN layer by exposing a substrate to multiple cycles of different corresponding precursor exposure pressures, in accordance with an embodiment. The resulting film may have at least two regions formed at different corresponding exposure pressures. Fig. 3B schematically illustrates a cross-sectional view of a semiconductor structure 350 including a TiN layer formed by an atomic layer deposition method in which a substrate is exposed to multiple cycles of different corresponding precursor exposure pressures, according to the method illustrated in fig. 3A. Referring to fig. 3A, a method 300 includes providing 310 a substrate including a nonmetallic surface in a reaction chamber configured for ALD (e.g., thermal ALD). Furthermore, the method 300 includes an initial stage (e.g., a nucleation stage) that includes forming 320 a first portion of the thin film on the substrate by exposing the semiconductor substrate to one or more first ALD cycles each including exposure to a first Ti precursor and a first N precursor at a first respective exposure pressure. The method 300 further includes a post stage (e.g., a bulk deposition stage) comprising forming 330 a second portion of the thin film on the first portion of the thin film by exposing the semiconductor substrate to one or more second ALD cycles each comprising exposure to a second Ti precursor and a second N precursor under a second corresponding exposure. The exposure to one or both of the Ti precursor and the N precursor during the one or more second ALD cycles is at a higher pressure relative to the corresponding exposure to one or both of the Ti precursor and the N precursor during the one or more first ALD cycles.

Referring to fig. 3B, a cross-sectional view of a semiconductor thin film structure 350 including a substrate 360, the substrate 360 in turn including a non-metallic surface, e.g., a dielectric and/or semiconductor surface. A first portion 370 of a thin film comprising TiN is formed on the substrate 360 and a second portion 380 of the thin film is formed on the first portion 370. The first portion 370 and the second portion 380 are formed by an atomic layer deposition method illustrated in fig. 3A in which the substrate 360 is exposed to first and second cycles having different corresponding precursor exposure pressures. Since the first portion 370 may be grown in a layer-by-layer growth mode in an initial stage (e.g., nucleation stage) as discussed above, at least the first portion 370 or both the first portion 370 and the second portion 380 may be substantially free of adjacent crystals with different orientations characterized by columnar growth of V-shaped grains and relatively high (e.g., 10% of thickness) surface roughness. The resulting TiN layer has superior properties including one or more of relatively high conformality or step coverage, lower surface roughness, smaller average grain size, higher conductivity and/or barrier properties relative to comparable thin film layers formed at a single pressure during the nucleation and bulk deposition phases.

As described herein and throughout the specification, it will be appreciated that the semiconductor substrate on which the TiN film according to embodiments is formed may be implemented with a variety of substrates, including, but not limited to, doped semiconductor substrates that may be formed from: group IV elemental materials (e.g., si, ge, C, or Sn) or alloys formed from group IV materials (e.g., siGe, siGeC, siC, siSn, siSnC, geSn, etc.); a group III-V compound semiconductor material (e.g., gaAs, gaN, inAs, etc.) or an alloy formed from a group III-V material; group II-VI semiconductor materials (CdSe, cdS, znSe, etc.) or alloys formed from group II-VI materials.

According to certain embodiments, the substrate may also be implemented as a semiconductor-on-insulator, such as a silicon-on-insulator (SOI) substrate. SOI substrates typically include those in which the various structures described above are formed using, for example, buried SiO ₂ The insulator layer of the layer is a silicon-insulator-silicon structure isolated from the support substrate. In addition, it will be appreciated that the various structures described herein may be formed at least in part in an epitaxial layer formed at or near a surface region.

Further, the substrate may include various structures formed thereon, such as diffusion regions, isolation regions, electrodes, vias, and lines, to name a few, any structure including TiN layers according to embodiments may be formed thereon, including topological features (such as vias, cavities, holes, or trenches) having one or more semiconductor or dielectric surfaces. Thus, the non-metallic surface on which the TiN layer according to the embodiment is formed may include: a semiconductor surface, e.g., a doped or undoped Si surface; and/or a dielectric surface, such as an inter-layer dielectric (ILD) surface, a mask or hard mask surface, or a gate dielectric surface, to name a few, which may include an inorganic insulator, an oxide, a nitride, a high-K dielectric, a low-K dielectric, or carbon, to name a few dielectric materials.

As described herein and throughout the specification, a reactor chamber refers to any reaction chamber that includes a single wafer processing reaction chamber or a batch wafer processing reaction chamber suitably configured for thermal Atomic Layer Deposition (ALD). In a thermal ALD reactor, the substrate may be placed on a suitable substrate holder, such as a susceptor or carrier boat (carrier boat). The substrate may be heated directly by conduction through the heated susceptor, or indirectly by radiation from a radiation source such as a lamp, or by convection through the heated chamber walls.

Typically, in an ALD process, reactants or precursors (e.g., oxidation and reduction reactants) are alternately introduced into a reaction chamber in which a substrate is disposed. The introduction of one or more reactants or precursors may, in turn, alternate with purging and/or pumping processes for removing excess reactants or precursors from the reaction chamber. Reactants may be introduced into the reaction chamber under conditions over a suitable period of time such that the surface of the substrate becomes at least partially saturated with precursors or reactants and/or reaction products of the reactants. Excess or residual precursor or reactant may then be removed from the substrate, such as by purging and/or evacuating the reaction chamber. The pumping process may be performed by a suitable vacuum pumping process and the purging step may be performed by introducing a non-reactive or inert gas (e.g., nitrogen or noble gas) into the reaction chamber. In the context of a layer formed by thermal ALD in the examples below, there are typically two types of precursors or reactants, namely, nitrogen (N) precursors and titanium (Ti) precursors.

Referring now to fig. 4, an exemplary implementation of a method 300 (fig. 3A) of forming a thin film comprising TiN with at least two regions formed by exposing a substrate to multiple cycles of different corresponding precursor exposure pressures by ALD (e.g., thermal ALD), according to an embodiment.

Atomic layer deposition of TiN by exposing a substrate to multiple cycles of different corresponding precursor exposure pressures

Referring again to fig. 3A, after providing 310 a substrate (substrate 360 in fig. 3B) including a non-metallic surface in a reaction chamber, method 300 continues by Atomic Layer Deposition (ALD) (e.g., thermal ALD) forming 320 a first portion of a thin film on the non-metallic surface by exposing the semiconductor substrate to one or more first ALD cycles, followed by forming a second portion of the thin film by exposing the semiconductor substrate to one or more second ALD cycles. The exposure pressure applied during the first and second ALD cycles is described graphically hereinafter.

Fig. 4 schematically illustrates pressure traces corresponding to exposure of a substrate to Ti and N precursors during a first cycle 400A or stage (e.g., nucleation stage) for forming a first portion 370 (fig. 3B) of a thin film and a second cycle 400B or stage (e.g., bulk growth stage) for forming a second portion 380 (fig. 3B) of a thin film, according to various embodiments. Referring to fig. 4, a first portion of a thin film is formed by exposing a semiconductor substrate to one or more first ALD cycles 400A each comprising one or more exposures 404 or exposure pulses to a partial pressure of a first Ti precursor and one or more exposures 408 or exposure pulses to a partial pressure of a first N precursor. A second portion of the thin film is formed by exposing the semiconductor substrate to one or more second ALD cycles 400B each comprising one or more exposures 412 or exposure pulses to the partial pressure of the second Ti precursor and one or more exposures 416 or exposure pulses to the partial pressure of the second N precursor.

As schematically depicted, each of the exposure 404 to the first Ti precursor, the exposure 408 to the first N precursor, the exposure 412 to the second Ti precursor, and the exposure 416 to the second N precursor may have a different partial pressure state (region), including corresponding partial pressure rise states 404A, 408A, 412A, and 416A, main exposure states 404B, 408B, 412B, and 416B, and partial pressure drop states 404C, 408C, 412C, and 416C. Each of the partial pressure rise states 404A, 408A, 412A, and 416A may correspond to a respective precursor introduced into a reaction chamber, for example. Each of the primary exposure states 404B, 408B, 412B, and 416B may correspond to a period during which the amount of the respective precursor in the reaction chamber is relatively constant. For example, a pressure sensor or throttle valve may be used to maintain a relatively constant amount of the respective precursor. Each of the partial pressure drop states 404C, 408C, 412C, and 416C may correspond to, for example, a state when the respective precursor is purged or pumped from the reaction chamber.

Still referring to fig. 4, it will be appreciated that in some implementations, the precursor may be pumped and/or purged after each exposure. In some implementations in which the precursor may be withdrawn without purging, the reaction chamber pressure may be substantially represented by the partial pressure of the respective precursor, and the pressure traces of the exposures 404, 408, 412, and 416 may be substantially representative of the reaction chamber pressure or precursor partial pressure during the respective exposures. In some implementations in which the precursor is purged with an inert gas without being withdrawn, the reaction chamber pressure may be represented by a total reaction chamber pressure 404P, 408P, 412P, and 416P corresponding to the exposures 404, 408, 412, and 416, where the total reaction chamber pressure is derived from a mixture of the respective precursor and inert gas.

Indeed, a combination of pumping and purging may be used for higher throughput and improved film quality. In these implementations, the substrate may be subjected to partial pressures of the first Ti precursor, the first N precursor, the second Ti precursor, and the second N precursor when the total pressures 404P, 408P, 412P, and 416P, including during purging and pumping, are measured. In some embodiments, the total chamber pressure may be kept relatively constant throughout a given precursor exposure or exposure pulse while using a pressure sensor and replacing the removed precursor with an inert gas to adjust pumping power. In these implementations, the one or more first ALD 400A cycles used in forming the first portion (370 in fig. 3B) may each include one or more exposures 404 to the partial pressure of the first Ti precursor (when the measured parameter may be the total reaction chamber pressure 404P) and one or more exposures 408 to the partial pressure of the first N precursor (when the measured parameter may be the total reaction chamber 408P). Similarly, the one or more second ALD cycles 400B used to form the second portion (380 in fig. 3B) may each include one or more exposures 412 to the partial pressure of the second Ti precursor (when the measured parameter may be the total pressure 412P) and one or more exposures 416 to the partial pressure of the second N precursor (when the measured parameter may be the total pressure 416P).

According to various embodiments, the measured total reaction chamber pressure may be proportional to the partial pressure of the precursor during exposure to the precursor. Thus, higher total pressures 412P and 416P relative to total pressures 404P and 408P, respectively, correspond to higher partial pressures of the second Ti precursor and the second N precursor relative to the partial pressures of the first Ti precursor and the first N precursor, respectively. However, embodiments are not so limited and in other embodiments, the higher total pressures 412P and 416P relative to the total pressures 404P and 408P, respectively, may correspond to the same or lower partial pressures of the second Ti precursor and the second N precursor relative to the first Ti precursor and the first N precursor, respectively.

Referring again to the illustrated method 300 in fig. 3A, one or both of the exposure pressures of the second Ti precursor and the second N precursor during one or more second ALD cycles in a later (e.g., bulk deposition) phase are higher relative to the corresponding one or both of the exposure pressures of the first Ti precursor and the first N precursor during one or more first ALD cycles in an initial (e.g., nucleation) phase. In some embodiments, the exposure pressure may be the partial pressure of the precursor or the total pressure of the reaction chamber. Thus, in various embodiments, referring to fig. 4, one or both of the exposure 412 to the second Ti precursor and the exposure 416 to the second N precursor may be at a higher partial pressure and/or a higher total reaction chamber pressure relative to the exposure 404 to the first Ti precursor and the exposure 408 to the corresponding one or both of the first N precursor, respectively.

Still referring to fig. 4, in various embodiments, the respective partial pressures or total pressures between the respective exposures to Ti and N precursors during the first cycle 400A and the second cycle 400B may be the respective partial pressures or total pressures during any of the partial pressure rise states 404A, 408A, 412A, and 416A, the main exposure states 404B, 408B, 412B, and 416B, and the partial pressure drop states 404C, 408C, 412C, and 416C. For example, one or both of the second Ti precursor and the second N precursor may be exposed 412, 416 during the second ALD cycle 400B during the main exposure states 412B and 416B, respectively, at a higher total pressure or partial pressure than one or both of the first Ti precursor and the first N precursor during the main exposure states 404B and 408B, respectively, during the first ALD cycle 400A. In various other implementations, the respective partial pressures or total pressures between the respective exposures to Ti and N precursors during the first cycle 400A and the second cycle 400B may be the respective average, mean, or peak partial pressures or total pressures during the exposures 404, 408, 412, and 416.

Still referring to fig. 4, in the illustrated embodiment, the total pressure and/or partial pressure during exposure 404 to the first Ti precursor and exposure 408 to the first N precursor is different, and the total pressure and/or partial pressure during exposure 412 to the second Ti precursor and exposure 416 to the second N precursor is different. However, embodiments are not so limited and in some embodiments, the total pressure and/or partial pressure during exposure 404 to the first Ti precursor and exposure 408 to the first N precursor may remain constant and/or the total pressure and/or partial pressure during exposure 412 to the second Ti precursor and exposure 416 to the second N precursor may remain constant.

Still referring to fig. 4, each of the total pressures during exposure 404 to the first Ti precursor and exposure 408 to the first N precursor (which may be the same or different) may be 0.01-0.2 torr, 0.2-0.4 torr, 0.4-0.6 torr, 0.6-0.8 torr, 0.8-1.0 torr, 1.0-1.5 torr, 1.5-2.0 torr, 2.0-2.5 torr, 2.5-3.0 torr, or a pressure within a range defined by any of these values. Each of the total pressures during exposure 412 to the second Ti precursor and exposure 416 to the second N precursor (which may be the same or different) may be 3.0-4.0 torr, 4.0-5.0 torr, 5.0-6.0 torr, 6.0-7.0 torr, 7.0-8.0 torr, 8.0-9.0 torr, 9.0-10.0 torr, 10.0-11.0 torr, 11.0-12.0 torr, or a pressure within a range defined by any of these values. The ratio of the total pressure (measured in torr) of the reaction chamber during exposure 412 to the second Ti precursor and exposure 404 to the first Ti precursor may be 2-5, 5-10, 10-20, 20-50, 50-100, or within a range defined by any of these values. Similarly, the ratio of the total pressure of the reaction chamber during exposure 416 to the second N precursor and exposure 408 to the first N precursor may be 2-5, 5-10, 10-20, 20-50, 50-100, or within a range defined by any of these values. In each of the exposures 404, 408, 412, and 416, the respective Ti or N precursor may constitute 1-2%, 2-5%, 5-10%, 10-20%, 20-50%, 50-100% of the total amount of gas molecules in the reaction chamber, or a percentage within a range defined by any of these values.

Still referring to fig. 4, according to various embodiments, the total or partial pressure during exposure 404 to the first Ti precursor and exposure 408 to the first N precursor, as well as the flow of the corresponding precursor and inert gas and the pumping power of the reaction chamber, are controlled such that the deposition rate during the first cycle 400A or phase is at every cycle including exposure 404 to the first Ti precursor and exposure 408 to the first N precursorCycle, < >>Cycle, < >>Cycle, < >>Cycle, < >>Cycle or values within a range defined by any of these values. The total or partial pressure during exposure 412 to the second Ti precursor and exposure 416 to the second N precursor, as well as the flow of the corresponding precursor and inert gas and the pumping power of the reaction chamber, are controlled such that the deposition rate during the second cycle 400B or phase is +.>Circulation(s),Cycle, < >>Cycle, < >>Circulation/circulationRing(s)>Circulation(s),Cycle, < >>Cycle or values within a range defined by any of these values. The ratio of the deposition rate per cycle during the second cycle 400B to the deposition rate per cycle during the first cycle 400A may be 1-1.5, 1.5-2.0, 2.5-3.0, or a ratio within a range defined by any of these values.

The inventors have found that various technical advantages of the TiN films disclosed herein may be achieved when forming 320 (fig. 3A) a first portion 370 (fig. 3B) of a film comprising TiN and forming 330 (fig. 3A) a second portion 380 (fig. 3B) of the film, each comprising exposing a semiconductor substrate to 1-25 cycles, 26-50 cycles, 50-100 cycles, 100-200 cycles, 200-300 cycles, 300-400 cycles, 400-500 cycles, 500-600 cycles, or values within a range defined by any of these values, respectively, of the first cycle 400A (fig. 4) and the second cycle 400B (fig. 4). According to various embodiments, the ratio of the number of second cycles to the number of first cycles may be greater than 1, 2, 5, or 10 or a ratio within a range defined by any of these values, or less than 1, 0.5, 0.1, or 0.1 or a ratio within a range defined by any of these values. The total thickness of the film including the first portion 370 (fig. 3B) and the second portion 380 (fig. 3B) including TiN may have a combined stack thickness of no more than about 25nm, 20nm, 15nm, 10nm, 7nm, 4nm, 2nm, or having a value within a range defined by any of these values. The thickness ratio between the first portion 370 (fig. 3B) and the second portion 380 (fig. 3B) may be about 1:20-1:10, 1:10-1:5, 1:5-1:2, 1:2-1:1, 1:1-2:1, 2:1-5:1, 5:1-10:1, 10:1-20:1, or a ratio within a range defined by any of these values. It will be appreciated that in some embodiments, for example, the first portion 370 (fig. 3B) may be relatively thinner when higher conformality may be more important than lower film roughness, while in other embodiments, for example, the second portion 380 (fig. 3B) may be relatively thinner when lower film roughness may be more important than higher conformality.

Still referring to fig. 4, each of the substrate exposure 404 to the first Ti precursor and the substrate exposure 412 to the second Ti precursor is such that the surface of the substrate is substantially or partially saturated with the first Ti precursor or the second Ti precursor, respectively. After the substrate exposure 404 to each of the first Ti precursor and the substrate exposure 412 to the second Ti precursor, excess or residual first and/or second Ti precursor or reaction products thereof that have not remained adsorbed or chemisorbed on the surface of the substrate may be pumped and/or purged.

Similarly, each of the substrate exposure 408 to the first N-precursor and the substrate exposure 416 to the second N-precursor is such that the substrate is substantially or partially saturated with the first N-precursor or the second N-precursor, respectively. After the substrate exposure 408 to each of the first N-precursor and the substrate exposure 416 to the second N-precursor, excess or residual first and/or second N-precursor or reaction products thereof that do not remain adsorbed or chemisorbed on the surface of the substrate may be pumped and/or purged. Subjecting the substrate to one or more exposures to the first Ti precursor and one or more exposures to the first N precursor may form about a monolayer or less per TiN cycle. Similarly, subjecting the substrate to one or more exposures to the second Ti precursor and one or more exposures to the second N precursor may form about a monolayer or less per TiN cycle.

In some embodiments, the exposure 404 to the first Ti precursor, the exposure 408 to the first N precursor, the exposure 412 to the second Ti precursor, and/or the exposure 416 to the second N precursor may be performed sequentially multiple times prior to the introduction of the other precursors. For example, it may be advantageous in some circumstances, for example, to expose the substrate to the Ti precursor and/or the N precursor more than once in the presence of a substantial steric effect, resulting in a higher level of surface saturation.

Still referring to fig. 4, it will be appreciated that the relative order of exposure to the first Ti precursor and the first N precursor may be selected depending on the race condition. In some implementations, the first Ti precursor advantageously may be the first precursor to which the substrate surface is exposed. For example, one or more direct exposures of the Si surface to the first Ti precursor may result in the formation of one or more monolayers in TiSi and prevent the formation of SiN, which in turn may be advantageous in reducing the contact resistance between the underlying Si and the TiN layer formed thereabove. However, in some other implementations, the first N precursor may advantageously be the first precursor to which the substrate is exposed. For example, by directly exposing the Si substrate to the first N precursor, one or more monolayers in SiN may be intentionally formed, which may be advantageous for improving the barrier properties of the stack.

It will be appreciated that in various embodiments, the frequency and repetition rate of exposure of the substrate to the first Ti reactant and/or the first N precursor in each of the first cycles 408A and to the second Ti reactant and/or the second N precursor in each of the second cycles 408B may be varied to obtain a desired thickness and stoichiometry based on various considerations including susceptibility to steric effects of the precursors.

According to various embodiments, non-limiting examples of the first and second Ti precursors that may be the same or different for forming the first and second portions of the TiN layer according to embodiments include titanium tetrachloride (TiCl ₄ ) Tetra (dimethylamino) titanium (TDMAT) or tetra (diethylamino) titanium (TDEAT). It may be advantageous to have the same precursor for the first and second portions of TiN, e.g., lower cost and/or easier process design. However, for example, for different deposition characteristics or film qualities, it may be advantageous to have different precursors for the first and second portions of TiN.

According to various embodiments, non-limiting examples of the first and second N precursors, which may be the same or different for forming the first and second portions of the TiN layer according to embodiments, include ammonia (NH ₃ ) Hydrazine (N) ₂ H ₄ ) Or monomethyl hydrazine (CH) ₃ (NH)NH ₂ "MMH"). It may be advantageous to have the same precursor for the first and second portions of TiN, e.g., lower cost and/or easier process design. However, for example, for different deposition characteristics or film qualities, it may be advantageous to have different precursors for the first and second portions of TiN.

According to eachIn various embodiments, non-limiting examples of inert gases for purging may include nitrogen N ₂ Or a rare gas (such as Ar or He).

According to embodiments, the various technical advantages and benefits described herein may be realized when one or both of the first portion 370 and the second portion 380 (fig. 3B) of the thin film comprising TiN are formed at a substrate temperature of 350 ℃ to 800 ℃, 450 ℃ to 750 ℃, 500 ℃ to 700 ℃, 550 ℃ to 650 ℃, or within a range defined by any of these values (e.g., about 600 ℃). Maintaining the same temperature during growth of the first and second portions 370, 380 may facilitate process control of the throughput because temperature adjustment during the process may require a long time.

In various embodiments, the exposure time or pulse time of each of the first and second Ti precursors and the first and second N precursors may be in the range of about 0.1-1sec, 1-10sec, 10-30sec, 30-60sec, or may be a duration in the range defined by any of these values.

Advantageously, when a TiN layer is formed using an atomic layer deposition method in which a substrate is exposed to multiple cycles of different corresponding precursor exposure pressures, according to various embodiments, one or both of surface roughness and resistivity may be substantially reduced to conventional TiN films including TiN films formed using other ALD processes having a single pressure set point. When deposited, a film comprising TiN formed according to the methods described herein and having the thickness described above and the thickness ratio between the first portion 370 and the second portion 380 (fig. 3B) may have a Root Mean Square (RMS) surface roughness of 3%, 4%, 5%, 6%, 7%, 8%, and 9% or values within a range defined by any of these values, based on the average thickness of the film. Alternatively, when deposited, a film comprising TiN having the thickness described above and the thickness ratio between the first portion 370 and the second portion 380 (fig. 3B) may have an RMS surface roughness value of less than 2.5nm, 2nm, 1.5nm, 1.0nm, 0.5nm, or a value within a range defined by any of these values.

When deposited, a film comprising TiN formed according to the methods described herein and having the thickness and thickness ratio between the first portion 370 and the second portion 380 (fig. 3B) described above may have a resistivity of <70 μΩ -cm, 70-100 μΩ -cm, 100-130 μΩ -cm, 130-160 μΩ -cm, 160-190 μΩ -cm, 190-220 μΩ -cm, 220-250 μΩ -cm, 250-280 μΩ -cm, 280-310 μΩ -cm, or greater than 310 μΩ -cm, or a value within a range defined by any of these values (e.g., less than about 200 μΩ -cm).

In addition to reducing surface roughness and resistivity, films comprising TiN formed according to the methods disclosed herein also have high conformality when deposited in high aspect ratio structures. In the context of high aspect ratio structures, one measure of conformality is referred to herein as step coverage. For example, the high aspect ratio structure may be a via, hole, trench, cavity, or similar structure. By way of illustrative example, fig. 5 schematically illustrates a semiconductor structure 500 having an exemplary high aspect ratio structure 516 formed therein to illustrate some exemplary metrics that define and/or measure the conformality of a thin film formed on the high aspect ratio structure. The illustrated high aspect ratio structure 516 is lined with TiN layers 512 having different thicknesses at different portions thereof. As described herein, the high aspect ratio structure has an aspect ratio exceeding 1, e.g., defined as the ratio of the depth or height (H) of the high aspect ratio structure 516 divided by the width (W) at the opening area. In the illustrated example, the high aspect ratio structure 516 is a via formed through a dielectric layer 508, such as an inter-metal dielectric (ILD) layer, formed on the semiconductor substrate 504 such that a bottom surface of the high aspect ratio structure 516 exposes the underlying semiconductor 504.TiN layer 512 may coat different surfaces of high aspect ratio structure 516 with different thicknesses. As described herein, one metric for defining or measuring the conformality of a thin film formed at high aspect ratio is referred to as step coverage. Step coverage may be defined as the ratio between the thickness of the film at the lower or bottom region of the high aspect ratio structure and the thickness of the film at the upper or top region of the high aspect ratio structure. The upper or top region may be a region of the high aspect ratio structure at a relatively small depth (e.g., at 0-10% or 0-25% of H measured from the top of the opening). The lower or bottom region may be a region of the high aspect ratio structure at a relatively large depth (e.g., at 90-100% or 75-100% of H measured from the top of the opening). In some high aspect ratio structures, step coverage may be defined or measured by the ratio of the thickness of thin film 512A formed at the bottom surface of the high aspect ratio structure to the thickness of thin film 512C formed on top of the high aspect ratio structure or at the top sidewall surface. However, it will be appreciated that some high aspect ratio structures may not have a well-defined bottom surface or a bottom surface with a small radius of curvature. In these structures, step coverage may be more consistently defined or measured by the ratio of the thickness of film 512B formed under the high aspect ratio structure or at the bottom sidewall surface to the thickness of film 512C formed over the high aspect ratio structure or at the top sidewall surface.

As described above, thin films comprising TiN formed according to the methods disclosed herein result in reduced surface roughness and resistivity while also providing high conformality in high aspect ratio structures. According to various embodiments, high aspect ratio structures having aspect ratios exceeding 1, 2, 5, 10, 20, 50, 100, 200, or values within a range defined by any of these values may be conformally coated with TiN films at step coverage exceeding 70%, 80%, 90%, 95%, or having values within a range defined by any of these values, as defined herein, according to embodiments.

Physical properties of TiN formed by exposing a substrate to multiple cycles of different corresponding precursor exposure pressures Sex toy

Fig. 6 is a graph illustrating experimentally measured Root Mean Square (RMS) surface roughness trends 604 and step coverage trends 608 over a total of 600 combined first cycles (e.g., nucleation phase) and second cycles (e.g., bulk deposition phase) at a relatively low chamber pressure of 0.5 torr, as a function of the number of first cycles exposed to Ti and N precursors. The second cycle of exposure to Ti and N precursors is at a relatively high chamber pressure of 5 torr. Each experimental data point in fig. 6 was grown from SiO for surface roughness measurement ₂ TiN film on coated primary Si substrate and grown on SiO ₂ And having an aspect ratio of about 40:1. The measured deposition rates for the first and second cycles are, respectivelyCirculation/circulation->Cycle. Experimental data are in the use of 0 first cycles (+.> ) Second cycle/(600->) 50 first cycles (+)>) 550 second cycles (/ ->) 200 first cycles (+)>) Second cycle of>) And 600 first cycles (>) Second cycle of->) The growth was measured on four different TiN films. The four TiN films have about +.>Is->Is included in the total thickness of the steel sheet. As described above, the measured surface roughness value of TiN films decreases as the relative number of first cycles comprising exposure at relatively lower pressures increases. Without being bound by any theory, this may be because a lower growth rate tends to allow more surface diffusion, which tends to reduce surface roughness and promote layer-by-layer growth. The measured surface roughness values for films grown at 0 first cycles/600 second cycles, 50 first cycles/550 second cycles, and 200 first cycles/400 second cycles were about Is->Corresponding to about 9%, 8% and 6% based on the total thickness of the corresponding TiN film. In addition, as discussed above, the measured step coverage value of TiN films is higher for films grown with 0 first cycles/600 second cycles relative to films grown with 600 first cycles/0 second cycles. Without being bound by any theory, this may be because higher pressures tend to allow more precursor to reach the high aspect ratio bottom, which tends to improve step coverage. Surprisingly, however, the inventors have found that up to about 50 first cycles (8% of the total number of cycles), the increased number of first cycles actually improves step coverage. Thus, according to some embodiments, forming the first portion of the TiN film includes alternately exposing the semiconductor substrate to 1 to 50 cycles each including exposure to the first Ti precursor and exposure to the first N precursor at a relatively low exposure pressure of less than about 3 torr.

Figures 7A-9 illustrate a method of forming a semiconductor device by exposing a substrate to a solution having a phase, in accordance with an embodimentFurther experimental comparisons between TiN films grown with cycles of precursor exposure pressure and TiN films grown by exposing the substrate to multiple cycles of different corresponding precursor exposure pressures. Fig. 7A is a cross-sectional transmission electron micrograph of a high aspect ratio via lined with a TiN layer formed by an atomic layer deposition process in which the substrate is exposed to an ALD cycle at the same precursor exposure pressure corresponding to the second cycle. Fig. 7B and 7C are Transmission Electron Micrographs (TEMs) of TiN films grown using only a second cycle of exposure to Ti and N precursors at a relatively high chamber pressure of 5 torr. The TEM is formed by SiO ₂ An image of a via having an aspect ratio of about 40:1 taken at the upper (fig. 7B) and lower (fig. 7C) regions of the via. In contrast, fig. 8A and 8B are Transmission Electron Micrographs (TEMs) of TiN films grown using a combination of first and second cycles of exposure to Ti and N precursors at relatively low (0.5 torr) and high (5 torr) chamber pressures, according to an embodiment. The TEM is formed by SiO ₂ An image of a via having an aspect ratio of about 40:1 taken at the upper (fig. 8A) and lower (fig. 8B) regions of the via. Fig. 9 is a graph illustrating experimental statistical comparisons between measured step coverage 904 measured from the TEM micrographs shown in fig. 7A-7C and measured step coverage 908 measured from the TEM micrographs shown in fig. 8A-8B. The data points in fig. 9 represent the ratios taken from different locations within the lower region of the via and different locations within the upper region of the via. Although not readily apparent from the TEM images, the statistical comparison in fig. 9 clearly illustrates the higher median step coverage of 93% for TiN films deposited according to the embodiments and the median step coverage of 87% for TiN films deposited using a single exposure pressure. In addition, the statistical distribution of measured step coverage of TiN films deposited according to embodiments is substantially less than that of TiN films deposited using a single exposure pressure, indicating that the film roughness of the latter is significantly higher.

Atomic layer deposition of TiN films with increased (111) crystallographic texture

The TiN disclosed herein has a face centered cubic NaCl lattice structure. Thus, the surface atomic density is highest when the surface has a (111) orientation relative to a (200) orientation. The surface portion with a certain crystallographic orientation for TiN can be highly dependent on deposition conditions.

For certain applications of TiN films, such as DRAM capacitor electrodes, to meet the increasing demands of aggressive scaling, tiN films may need to be extremely thin (e.g., less than 30 nm) while meeting a stringent combination of electrical and mechanical properties. For example, in addition to low resistivity and high conformality as discussed above, some TiN films are required to meet a combination of stringent mechanical properties (e.g., relatively high density, hardness, and modulus) at the same time in order to reduce the risk of integration failure.

TiN films grown by atomic layer deposition may have grains with different crystal orientations, including (111) and (200) orientations at the surface, as well as other orientations. The inventors have found that TiN films textured to have a specific crystalline texture can have superior mechanical properties in addition to the desired low resistivity and conformality as described above. In particular, ultra-thin TiN films with relatively high (111) crystalline textures may have relatively high density, hardness, and modulus. In addition, the increased (111) crystal texture may reduce columnar growth, providing superior diffusion barrier properties. Without being bound by any theory, these advantageous properties of TiN films with relatively high (111) crystalline texture may be related to one of the highest surface atomic packing densities in the direction parallel to the growth surface and grain boundary alignment favoring superior physical properties. The inventors have further found that the texture of TiN films can be controlled by controlling certain conditions of the periodic vapor deposition cycle, as described herein. In particular, the inventors have found that periodic vapor deposition cycles in which the substrate is subjected to relatively high flows of N precursor, as described herein, can result in TiN films grown with relatively high (111) crystalline textures.

Fig. 11 is a flow chart schematically illustrating an atomic layer deposition method 1100 of forming a TiN layer having a relatively high (111) crystalline texture by exposing a substrate to a relatively high N precursor flow, in accordance with an embodiment. The method 1100 includes providing 1110 a semiconductor substrate. Further, the method 1100 includes exposing 1120 the semiconductor substrate to one or more periodic vapor deposition cycles each including exposure to a Ti precursor at a Ti precursor flow rate and exposure to an N precursor at an N precursor flow rate. The method 1100 forms TiN films with relatively high (111) crystalline texture by exposing 1120 the semiconductor substrate to one or more periodic vapor deposition cycles in which the ratio of N precursor flow to Ti precursor flow (N/Ti flow ratio) and/or the flow of N precursor is significantly high compared to conventional methods. According to various embodiments, the ratio of N precursor flow to Ti precursor flow (N/Ti flow ratio) exceeds 3. According to various embodiments, the N precursor flow exceeds 500 seem. It will be appreciated that the exposure 1120 and formation 1130 are not necessarily in the order as shown. Various implementations of method 1100 are described herein.

The provision 1110 of a semiconductor substrate may be similar to the provision 310 of a semiconductor substrate according to various examples described above with reference to fig. 3A and 3B, the details of which are not repeated here for the sake of brevity. For example, the substrate may be patterned or non-patterned, and may have one or both of an insulating and conductive surface as described above.

Exposing 1120 the semiconductor substrate may be similar to exposing the semiconductor substrate to one or more first or second thermal ALD cycles, as described above with reference to fig. 3A, 3B, and 4, the details of which are not repeated here for brevity. For example, exposure to the Ti precursor at the Ti precursor flow rate may be consistent with exposure 404 to the first Ti precursor (fig. 4) or exposure 412 to the second Ti precursor (fig. 4). Similarly, exposure to the N precursor at the N precursor flow may be consistent with exposure 408 to the first N precursor (fig. 4) or exposure 416 to the second N precursor (fig. 4). For brevity, details of these processes are not repeated here. According to various embodiments, exposure 1120 is such that a TiN film with high (111) crystal texture is formed, as described herein.

According to various embodiments, the Ti precursor and the N precursor may be any of the above precursors. For example, the Ti precursor may be titanium tetrachloride (TiCl ₄ ) And the N precursor may be ammonia (NH) ₃ )。

Various other process parameters including substrate temperature, chamber pressure, and exposure time may be consistent with the various process parameters described above, the details of which are not repeated here for the sake of brevity.

According to an embodiment, exposure 1120 is such that the ratio of N precursor flow to Ti precursor flow (N/Ti flow ratio) exceeds 2. The ratio may exceed 2, 3, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or have a value within a range defined by any of these values.

According to an embodiment, exposure 1120 is such that the N precursor flow exceeds 200 seem. For example, the N precursor flow may exceed 200 seem, 500 seem, 1000 seem, 2000 seem, 3000 seem, 4000 seem, 5000 seem, 6000 seem, 7000 seem, 8000 seem, 9000 seem, 10000 seem, or have a value within a range defined by any of these values.

According to an embodiment, exposure 1120 is such that the Ti precursor flow exceeds 100 seem but does not exceed the N precursor flow, according to the N/Ti flow ratio described above. For example, the Ti precursor flow may exceed 100 seem, 200 seem, 500 seem, 1000 seem, 2000 seem, 3000 seem, 4000 seem, 5000 seem, or have a value within a range defined by any of these values.

Fig. 12A illustrates an experimental X-ray diffraction spectrum of the resulting TiN film with a relatively high (111) crystalline texture according to an embodiment. X-ray diffraction spectra were taken for examples 1-4 shown in Table 1 below. Fig. 12B is a graph illustrating an experimental ratio of the peak height of an X-ray diffraction peak corresponding to the (111) crystal orientation of TiN to the peak height of an X-ray diffraction peak corresponding to the (200) crystal orientation of TiN obtained from the X-ray diffraction spectrum of fig. 12A. The illustrated TiN film is shown by way of example only, and the embodiments are not limited thereto. According to an embodiment, the N-precursor flow range and the Ti-precursor flow range are such that the TiN film has a relatively high (111) crystalline texture relative to a comparable film (e.g., tiN having a similar thickness) formed by exposing the semiconductor substrate to periodic vapor deposition cycles that each include a different Ti-precursor flow range exposed outside of the above-described Ti-precursor flow range and a different N-precursor flow range exposed outside of the above-described N-precursor flow range. The degree of increased (111) texture may be measured using, for example, X-ray diffraction. For example, the relative intensities of the different X-ray peaks may provide at least a semi-quantitative indication of the degree of texturing. TiN films formed according to embodiments advantageously have a relatively high (111) crystalline texture such that the X-ray spectrum of the film has a ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystalline orientation to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystalline orientation of more than 0.4. For example, this ratio may exceed 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, or a value within a range defined by any of these values. Table 1 summarizes the selected experimental precursor flow conditions and corresponding ratio measurements.

Fig. 13 is a graph of experimental thickness and resistivity measurements of TiN films with relatively high (111) crystalline textures, according to an embodiment. For examples 1-4 listed in Table 1, increasing the N/Ti flow ratio reduced the thickness for the same number of cycles. Unexpectedly, unlike conventional methods, increasing the N/Ti flow ratio, which in turn reduces the thickness, reduces the resistivity of TiN films. Prior to the present disclosure, the decrease in thickness was related to the increase in resistivity, which has been related to the use of TiCl ₄ The relatively high amount of chlorine in the relatively thin TiN film formed is related. The illustrated TiN film is shown by way of example only, and the embodiments are not limited thereto. Advantageously, tiN films formed according to embodiments have a resistivity of less than about 200 μΩ -cm, or any of the values described above. Table 1 summarizes the selected experimental precursor flow conditions and the corresponding measurements of thickness and resistivity.

TABLE 1

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Fig. 14 is a graph of experimental hardness and modulus measurements for TiN films having substantially the same thickness and preferential (111) crystallographic texture, according to an embodiment. Fig. 15 is a graph of experimental hardness measurements for TiN films with relatively high (111) crystalline textures for two different thicknesses, according to an embodiment. According to an embodiment, the N/Ti flow ratio is increased, which in turn reduces the thickness, increasing the young's modulus and hardness of the TiN film. The illustrated TiN film is shown by way of example only, and the embodiments are not limited thereto. Advantageously, the TiN film formed according to the embodiment has a hardness exceeding 6GPa. For example, the hardness may exceed 6Gpa, 10Gpa, 14Gpa, 18Gpa, 22Gpa, 25Gpa, or have a value within a range defined by any of these values. Advantageously, the TiN film formed according to the embodiment has an elasticity or young's modulus exceeding 150Gpa. For example, the young's modulus may exceed 150Gpa, 170Gpa, 190Gpa, 210Gpa, 230Gpa, 250Gpa, 270Gpa, 300Gpa, or have a value within a range defined by any of these values.

According to the methods described herein, lowering the deposition pressure increases the ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystallographic orientation of TiN to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystallographic orientation of TiN. This is illustrated in fig. 16, which illustrates experimental X-ray spectra of TiN films formed at different exposure pressures and having a preferential (111) crystalline texture, according to an embodiment. The illustrated TiN film is shown by way of example only, and the embodiments are not limited thereto. In particular, the X-ray diffraction spectrum was performed for TiN films having the same thickness but formed at two different exposure pressures (i.e., 5 torr and 3 torr). The results indicate that lower pressures can lead to further increases in (111) crystal texture. However, the inventors have recognized that in some cases, lower exposure pressures can result in impaired step coverage. Thus, in these cases, according to an embodiment, after forming 1130 (fig. 11) a TiN film having a relatively high (111) crystalline texture, method 1100 (fig. 11) may further include forming a second TiN film on the TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor and to a second N precursor, wherein one or both of the second Ti precursor and the second N precursor is exposed at a higher pressure during the one or more second periodic vapor deposition cycles relative to corresponding exposure to one or both of the Ti precursor and the N precursor during the one or more first periodic vapor deposition cycles. Other exposure conditions corresponding to forming 1130 (fig. 11) the TiN film and forming the second TiN film may be according to any of the exposure conditions described above with respect to fig. 3A, 3B, and 4.

Fig. 17 illustrates a chlorine concentration depth profile of a TiN film with increased (111) crystal texture according to an embodiment. Depth profile was obtained using secondary ion mass spectrometry. The films measured correspond to examples 1-4 listed in table 1. As described above, increasing the N/Ti flux ratio reduces the thickness for the same number of cycles. Unexpectedly, unlike conventional methods, increasing the N/Ti flow ratio, which in turn reduces the thickness, reduces the resistivity of TiN films. Fig. 17 illustrates this unexpected trend of resistivity decrease with decreasing thickness as a function of decreasing chlorine concentration. For the ranges of N/Ti flow ratios covered by examples 1-4, the amount of chlorine can be reduced by more than 50%. For example, for examples 1-4, chlorine concentrations of 7.2X10, respectively, were measured at about 10nm ²⁰ /cm ³ 、6.1x10 ²⁰ /cm ³ 、5.1x10 ²⁰ Cm3 and 3.5x10 ²⁰ /cm ³ . Prior to the present disclosure, the decrease in thickness has been correlated with an increase in chlorine content, which has been correlated with a relatively high resistivity.

Atomic layer deposition of bilayer TiN films with increased (111) crystallographic texture

As described above, high N/Ti flow ratios, high N precursor flows, and/or low deposition pressures may increase the (111) texture of the resulting TiN film. As further described above, high (111) texture can provide various advantages in a manner similar to low pressure deposited (e.g., less than 5 torr) TiN films as described above. Such advantages include improvements in resistivity, hardness, modulus, and roughness, to name a few. However, in some cases, a high N/Ti flow ratio may result in relatively low step coverage in a manner similar to that described above with respect to low pressure deposited TiN films. To compensate, it may be desirable to have a bilayer or multilayer process in which a second TiN film is grown on a first TiN film having a high (111) texture.

According to these embodiments, a method includes forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each including exposure to a Ti precursor at a Ti precursor flow and exposure to an N precursor at an N precursor flow. Further, the method includes forming a second TiN film on the TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow. The method is such that one or both of the TiN film and the second TiN film has a high (111) crystal texture such that an X-ray spectrum of the one or both of the TiN film and the second TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4.

According to some other embodiments, a method of forming a film comprising titanium nitride (TiN) by a periodic vapor deposition process includes forming a first TiN film on a semiconductor substrate at a first pressure by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposing to a first Ti precursor at a first Ti precursor flow and exposing to a first N precursor at a first N precursor flow. The first TiN film has a crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN exceeding 0.4. Further, the method includes forming a second TiN film on the first TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each including exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow at a second pressure higher than the first pressure. The second TiN film may be formed according to any of the first or second TiN films formed as part of the dual or multi-layer TiN film process described above, such as those described above with respect to fig. 3A, 3B, and 4.

According to these embodiments, the resulting TiN film includes a lower portion and an upper portion, wherein the lower portion and the upper portion may have different crystal textures. At least the lower portion of the film has a crystalline texture such that an X-ray diffraction spectrum of the film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to (111) crystalline orientation to a peak height or intensity of an X-ray diffraction peak corresponding to (200) crystalline orientation of more than 0.4. As described herein, the upper portion may have a similar or lower degree of (111) texture depending on the deposition conditions and the desired final film properties.

Advantageously, a second TiN film grown on the TiN film may benefit from the high (111) texture of the underlying first TiN film. In these cases, the second TiN film may also have a relatively high (111) texture, despite the fact that the second TiN film may not have a relatively high (111) texture if grown on another surface that does not have the high (111) TiN texture of the underlying first TiN film. For example, if grown on a different surface, e.g., a material other than TiN or TiN without a relatively high (111) texture, such as an insulating film (such as SiO ₂ Si or other material), the second TiN film may not have a relatively high (111) texture. For example, if grown on another surface, the second TiN layer may have a crystalline texture such that the X-ray spectrum of the TiN film has a ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystalline orientation of TiN to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystalline orientation of TiN that is substantially less than 0.4 (e.g., 0.3, 0.2, 0.1, or a value within a range defined by any of these values). This is because the textured surface of the underlying TiN film may serve as a template for a second or subsequent TiN film. Because the second or subsequent TiN film is not necessarily formed under high (111) texturing conditions, the second or subsequent TiN film may be formed under conditions where the overall performance of the combined TiN film is improved. For example, the second or subsequent TiN film may be grown under conditions that increase step coverage (e.g., at high pressure), as described above with respect to the various two-step deposition processes.

For example, as described above, the second TiN film may be formed at high pressure (e.g., greater than 3 or 5 torr) with or without a high N precursor flow and/or N/Ti precursor flow ratio, e.g., according to various two-step processes described with respect to fig. 3A and 3B. For example, by texturing the first TiN film to have a relatively high (111) orientation, initial film growth may be substantially performed in a pattern where the (111) texture is advantageous, which advantageously results in improved mechanical properties and resistivity as described above. On the other hand, during deposition of the second portion of the film, the latter portion of the film or the second TiN film may advantageously be grown with higher conformality or step coverage by subsequently exposing the substrate to the Ti and/or N precursor at a relatively high pressure (e.g., greater than 3 or 5 torr) relative to a first TiN film having a relatively high (111) texture, or relative to a TiN film deposited by exposing the substrate to the Ti and/or N precursor at a relatively low pressure (e.g., less than 3 torr or less than 1 torr).

Furthermore, because the first portion of the TiN film has a relatively high (111) texture, the second portion of the film can continue to grow in a layer-by-layer manner using the first portion as a template. The second TiN film may have a lower or comparable (111) texture relative to the underlying first TiN film.

According to various embodiments, the thickness ratio between the first and second TiN thin films may be 10%, 25%, 50%, 25%, 90% or a value within a range defined by any of these values, depending on the desired final film properties. For example, when a higher degree of (111) texture is desired, the thickness of the first TiN film may be 50% or more relative to the total thickness, and when a higher degree of conformality is desired, the thickness of the second TiN film may be 50% or more.

The resulting TiN film may have a (111) texture that is any fraction of the (111) texture value of the first TiN film, e.g., 10%, 25%, 50%, 25%, 90% or a value within a range defined by any of these values. The resulting Young's modulus and/or hardness may also have values defined by these values.

The resulting TiN film may have a conformality value that is any fraction of the conformality value of a second TiN film that does not have the underlying first TiN film, such as 10%, 25%, 50%, 25%, 90% or a value within a range defined by any of these values thereof.

As a final result, films comprising first and second portions deposited by depositing a relatively higher (111) textured first TiN film followed by depositing a second TiN film according to the methods disclosed herein advantageously have a combination of superior surface roughness and conformality when deposited on a particular surface (e.g., a surface comprising a non-metallic surface) relative to film layers formed on the same surface using a single step. Alternatively or in addition, due in part to the improved smoothness and conformality, the thin films have relatively low resistivity compared to TiN layers formed by some existing methods.

Application of

Films comprising TiN formed using different exposure pressures according to the various embodiments disclosed herein may be used in various applications, particularly where the substrate includes relatively high aspect ratio structures and/or non-metallic surfaces that may benefit from various advantageous properties of TiN layers as disclosed herein. Exemplary applications include depositing vias, holes, trenches, cavities, or similar structures having aspect ratios (e.g., defined as the ratio of depth divided by top width) exceeding 1, 2, 5, 10, 20, 50, 100, 200, or values within a range defined by any of these values.

By way of example, fig. 10 schematically illustrates an application in the context of a diffusion barrier for a contact structure (e.g., a source or drain contact) formed on an active semiconductor substrate region that may be heavily doped. A portion of a semiconductor device 1000 is illustrated that includes a substrate 1004 upon which a dielectric layer 1008 (e.g., an inter-layer or inter-metal dielectric (ILD) layer) comprising a dielectric material such as an oxide or nitride is formed. To form contacts to various regions of the substrate 1004, including various doped regions, such as source and drain regions, vias or trenches may be formed through the dielectric layer 1008. The via or the trench may expose various non-metallic surfaces, e.g. via The exposed bottom surface of the hole, including the substrate surface (e.g., silicon substrate surface), and dielectric sidewalls. The bottom and side surfaces of the via may be conformally coated with a first portion of a TiN layer (corresponding to first portion 370 in fig. 3B) formed in accordance with various embodiments described herein, followed by a second portion (corresponding to second portion 380 in fig. 3B). According to various embodiments disclosed herein, a conformal first portion may be formed directly on the inner surface of the via, followed by a conformal second TiN layer. Thereafter, the lined vias may be filled with a metal (e.g., W, al or Cu) to form contact plugs 1016. For example, WF can be used by CVD ₆ The vias are filled with tungsten.

The barrier layer 1012 formed in accordance with an embodiment may be advantageous for various reasons. In particular, due to the conformal nature of barrier layer 1012 formed by ALD, the propensity for pinch-off (pinch off) during subsequent metal filling processes may be substantially reduced. In addition, as described above, the barrier layer 1012 may provide an effective material transport barrier thereacross, e.g., dopant (B, P) out-diffusion from the substrate 1004, as well as in-diffusion of reactants, etchants, and metals (e.g., F, cl, W, or Cu) from the contact plug formation process. The barrier effect can be enhanced by reduced surface roughness and increased step coverage. Furthermore, as described above, the layer-by-layer growth mode may reduce the overall contact resistance of the barrier layer 1012. Furthermore, due to the reduced film roughness, a relatively thin barrier layer 1012 may be formed while still performing its desired barrier function, resulting in a further reduction in contact resistance.

Other applications of TiN layers formed according to various embodiments disclosed herein include conductive structures (e.g., buried electrodes or lines), electrodes (e.g., DRAM capacitor electrodes or gate electrodes), metallization barriers for higher metal levels (e.g., barriers in vias/trenches for Cu contacts/lines), high aspect ratio vertical rod electrodes, or vias and through-silicon vias (TSVs) for three-dimensional memories, to name a few).

Exemplary embodiment I:

1. a method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

a TiN film is formed on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposure to a Ti precursor at a Ti precursor flow and exposure to an N precursor at an N precursor flow,

wherein the ratio of the N precursor flow to the Ti precursor flow exceeds 3.

2. A method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

a TiN film is formed on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposure to a Ti precursor at a Ti precursor flow and exposure to a first N precursor at a first N precursor flow,

Wherein the N precursor flow exceeds 200sccm.

3. A method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

forming a TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more periodic vapor deposition cycles each comprising exposure to a Ti precursor at a Ti precursor flow in a Ti precursor flow range and exposure to an N precursor at an N precursor flow in an N precursor flow range,

wherein the N precursor flow range and the Ti precursor flow range are such that the TiN film has a preferential (111) crystalline texture relative to another TiN film formed by exposing the semiconductor substrate to a periodic vapor deposition cycle that each includes exposure to the Ti precursor in a different Ti precursor flow range outside the Ti precursor flow range and exposure to the N precursor in a different N precursor flow range outside the N precursor flow range.

4. The method of any of the above embodiments, wherein the ratio of the N precursor flow to the Ti precursor flow is 2-100.

5. The method of any of the above embodiments, wherein the N precursor flow is 200sccm to 10,000sccm.

6. The method of any of the above embodiments, wherein the Ti precursor flow is 100sccm-5000sccm.

7. The method of any of the above embodiments, wherein the TiN film has a preferential (111) crystalline texture such that the X-ray spectrum of the TiN film has a ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystalline orientation to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystalline orientation of more than 0.4.

8. The method of any of the above embodiments, wherein the TiN film has a hardness of more than 6 GPa.

9. The method of any of the above embodiments, wherein the TiN film has a young's modulus exceeding 150 GPa.

10. The method according to any of the preceding embodiments, further comprising:

forming a second TiN film on the TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each comprising exposing to a second Ti precursor and exposing to a second N precursor,

wherein exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a higher pressure relative to corresponding exposure to one or both of the Ti precursor and the N precursor during the one or more periodic vapor deposition cycles.

11. The method of embodiment 10, wherein one or both of the Ti precursor and the N precursor are exposed to a reactor pressure of less than about 5 torr during the one or more periodic vapor deposition cycles, and wherein one or both of the second Ti precursor and the second N precursor are exposed to a reactor pressure of greater than about 5 torr during the one or more second periodic vapor deposition cycles.

12. The method of embodiment 10 or 11, wherein exposure to each of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a higher pressure than corresponding exposure to each of the Ti precursor and the N precursor during the one or more periodic vapor deposition cycles.

13. The method of any of embodiments 10-12, wherein forming the TiN film comprises, with each periodic vapor deposition cycle, less thanThe periodic vapor deposition cycle including exposure of the semiconductor substrate to the Ti precursor and to the N precursor, and wherein forming the second TiN film includes forming a second TiN film at each second periodic vapor deposition cycle of greater than >The second periodic vapor deposition cycle includes exposing the semiconductor substrate to the second Ti precursor and to the second N precursor.

14. The method of any of the above embodiments, wherein the root mean square surface roughness of the film is less than about 8% of the thickness of the film.

15. The method of any of embodiments 10-14, wherein forming the TiN film and the second TiN film comprises depositing by thermal periodic vapor deposition.

16. The method of any of embodiments 10-15, wherein forming the TiN film comprises directly exposing one or both of a semiconductor surface and an insulator surface to the one or more periodic vapor deposition cycles.

17. The method of any of embodiments 10-16, wherein forming one or both of the TiN film and the second TiN film comprises growing in a layer-by-layer growth mode.

18. The method of any of embodiments 10-17, wherein forming the TiN film comprises alternately exposing the semiconductor substrate to 1 to 50 periodic vapor deposition cycles.

19. The method of any of embodiments 10-18, wherein forming the TiN film and the second TiN film comprises forming at a temperature between 400 ℃ and 600 ℃.

20. The method of any of the above embodiments, wherein the semiconductor substrate comprises a trench or via comprising an inner surface comprising a non-metallic sidewall surface in a trench or via having an aspect ratio exceeding 1, and wherein forming the thin film comprises conformally lining the inner surface, wherein a ratio of a thickness of the thin film formed on a lower 25% of a height of the trench or via to an upper 25% of the height of the trench or via exceeds 0.9.

21. The method of any of the above embodiments, wherein the film has a resistivity of less than about 200 μΩ -cm.

22. The method of any of embodiments 10-21, wherein the Ti precursor is the same as the second Ti precursor and the N precursor is the same as the second N precursor.

23. The method according to any one of embodiments 1-9, comprising:

providing the semiconductor substrate, wherein the semiconductor substrate comprises a groove or a through hole with an aspect ratio exceeding 1;

Forming the thin film in the trench or the via by exposing the semiconductor substrate to the one or more periodic vapor depositions to form the TiN thin film in the trench or the via; and

the semiconductor substrate is further exposed to one or more second periodic vapor deposition cycles each comprising exposing to a second Ti precursor and exposing to a second N precursor to form a second TiN film on the TiN film, wherein one or both of the Ti precursor and the N precursor are exposed to different pressures during the one or more periodic vapor deposition cycles relative to corresponding exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles.

24. The method of embodiment 23, wherein exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a higher pressure relative to corresponding exposure to one or both of the Ti precursor and the N precursor during the one or more periodic vapor deposition cycles.

25. The method of embodiment 23 or 24, wherein exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is 5 times or more higher than exposure to one or both of the Ti precursor and the N precursor during the one or more periodic vapor deposition cycles.

26. The method of any of embodiments 23-25, wherein forming the TiN film comprises alternately exposing the semiconductor substrate to 1 to 50 periodic vapor deposition cycles.

27. The method of any of embodiments 23-26, wherein forming the TiN film comprises exposing the semiconductor substrate to a first number of the one or more periodic vapor deposition cycles, and wherein forming the second portion comprises exposing the semiconductor substrate to a second number of second periodic vapor deposition cycles greater than twice the first number of the one or more periodic vapor deposition cycles.

28. The method of any of embodiments 23-27, wherein the root mean square surface roughness of the film is less than about 8% of the thickness of the film.

29. The method of any of embodiments 23-28, wherein forming the TiN layer comprises forming by thermal periodic vapor deposition at a temperature between 400 ℃ and 600 ℃.

30. The method of any of embodiments 23-29, wherein the trench or the via has an aspect ratio of more than 5 and an inner surface comprising a non-metallic sidewall surface, and wherein forming the thin film comprises conformally lining the inner surface, wherein a ratio of a thickness of the thin film formed on a lower 25% of a height of the trench or the via to an upper 25% of the height of the trench or the via exceeds 0.9.

31. The method of any of embodiments 23-29, wherein the Ti precursor is the same as the second Ti precursor and the N precursor is the same as the second N precursor.

32. A semiconductor structure, comprising:

a semiconductor substrate comprising non-metallic sidewall surfaces in trenches or vias having an aspect ratio exceeding 5; and

a film comprising TiN conformally lining the non-metallic sidewall surfaces,

wherein the film has a preferential (111) crystallographic texture such that the X-ray spectrum of the film has a ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystallographic orientation to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystallographic orientation of more than 0.4.

33. The semiconductor structure of embodiment 32, wherein the ratio exceeds 1.3.

34. The semiconductor structure of embodiments 32 and 33 wherein the film has a hardness in excess of 6 GPa.

35. The semiconductor structure of any of embodiments 32-34, wherein the thin film has a young's modulus exceeding 150 GPa.

36. The semiconductor structure of any of embodiments 32-35, wherein a ratio of a thickness of the thin film formed over a lower 25% of a height of the trench or the via to an upper 25% of the height of the trench or the via exceeds 0.9.

37. The semiconductor structure of any of embodiments 32-36, wherein the trench or the via has an aspect ratio exceeding 10.

38. The semiconductor structure of any of embodiments 32-37, wherein a root mean square surface roughness of the thin film formed on the non-metallic surface is less than about 8% based on an average thickness of the thin film.

39. The semiconductor structure of any of embodiments 32-38, wherein the trench or the via has dielectric sidewalls.

40. The semiconductor structure of any of embodiments 32-39 wherein the trench or the via has a bottom surface exposing semiconductor material of the semiconductor substrate.

41. The semiconductor structure of any of embodiments 32-40, wherein the thin film has a resistivity of less than about 200 μΩ -cm.

42. The semiconductor structure of any of embodiments 32-41 wherein the trench or the via lined with the thin film is filled with a metal comprising tungsten.

Exemplary embodiment II:

wherein the ratio of the N precursor flow to the Ti precursor flow (N/Ti flow ratio) exceeds 3, and

wherein the method forms the TiN film having a crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4.

2. The method of embodiment 1, wherein the N/Ti flow ratio is 3-100.

3. The method according to embodiment 1 or 2, wherein the method is such that increasing the N/Ti flow ratio decreases the thickness of the TiN film.

4. The method of any of embodiments 1-3, wherein increasing the N/Ti flow ratio reduces the resistivity of the TiN film.

5. The method of any of embodiments 1-4, wherein the method is such that increasing the N/Ti flow ratio increases the young's modulus of the TiN film.

6. The method of embodiment 5, wherein increasing the young's modulus comprises increasing to a value exceeding 150 GPa.

7. The method of any of embodiments 1-6, wherein the method is such that increasing the N/Ti flow ratio increases the hardness of the TiN film.

8. The method of embodiment 7, wherein increasing the hardness comprises increasing to a value exceeding 6 GPa.

9. The method of any of embodiments 1-8, wherein increasing the N/Ti flow ratio reduces the chlorine content of the TiN film.

10. The method of any of embodiments 1-9, wherein the method is such that lowering deposition pressure increases a ratio of the peak height or the intensity of the X-ray diffraction peak corresponding to the (111) crystal orientation of the TiN to the peak height or the intensity of the X-ray diffraction peak corresponding to the (200) crystal orientation of the TiN.

11. The method of any of embodiments 1-10, wherein the N precursor flow is 500sccm to 10,000sccm.

12. The method of any of embodiments 1-11, wherein the Ti precursor flow is 100sccm-5000sccm.

13. A method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

wherein the N precursor flow exceeds 500sccm, and

14. The method of embodiment 13, wherein the ratio of the N precursor flow to the Ti precursor flow (N/Ti flow ratio) is 3-100.

15. The method of embodiment 14, wherein the method is such that increasing the N/Ti flow ratio reduces the thickness of the TiN film.

16. The method of embodiment 15, wherein reducing the thickness reduces the resistivity of the TiN film.

17. The method of any of embodiments 15-16, wherein reducing the thickness increases the young's modulus of the TiN film.

18. The method of embodiment 17, wherein increasing the young's modulus comprises increasing to a value exceeding 150 GPa.

19. The method of any of embodiments 15-18, wherein reducing the thickness increases the hardness of the TiN film.

20. The method of embodiment 19, wherein increasing the hardness comprises increasing to a value exceeding 6 GPa.

21. The method of any of embodiments 15-20, wherein reducing the thickness reduces a chlorine content of the TiN film.

22. The method of any of embodiments 13-21, wherein lowering the deposition pressure increases a ratio of the peak height or intensity of an X-ray diffraction peak corresponding to the (111) crystallographic orientation of TiN to the peak height or intensity of an X-ray diffraction peak corresponding to the (200) crystallographic orientation of TiN.

23. The method of any of embodiments 13-22, wherein the N precursor flow is 500sccm to 10,000sccm.

24. The method of any of embodiments 13-23, wherein the Ti precursor flow is 100sccm-5000sccm.

25. A method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

forming a first TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposing to a first Ti precursor at a first Ti precursor flow and exposing to a first N precursor at a first N precursor flow,

Forming a second TiN film on the first TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each comprising exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow,

wherein the method is such that one or both of the first and second TiN films has a preferential (111) crystal texture such that the X-ray spectrum of the one or both of the first and second TiN films has a ratio of the peak height or intensity of the X-ray diffraction peak corresponding to the (111) crystal orientation of TiN to the peak height or intensity of the X-ray diffraction peak corresponding to the (200) crystal orientation of TiN of more than 0.4.

26. The method of embodiment 25, wherein exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a higher pressure relative to corresponding exposure to one or both of the first Ti precursor and the first N precursor during the one or more first periodic vapor deposition cycles.

27. The method of embodiment 26, wherein one or both of a first ratio of the first N precursor flow to the first Ti precursor flow (first N/Ti flow ratio) and a second ratio of the second N precursor flow to the second Ti precursor flow (second N/Ti flow) is 3-100.

28. The method of embodiment 27, wherein the method is such that increasing one or both of the first N/Ti flow ratio and the second N/Ti flow reduces the corresponding thickness of one or both of the first and second TiN films.

29. The method of embodiment 28 wherein reducing the corresponding thickness reduces the corresponding resistivity of the one or both of the first and second TiN films.

30. The method of embodiment 28 or 29, wherein reducing the corresponding thickness increases the corresponding young's modulus of the one or both of the first and second TiN films.

31. The method of embodiment 30, wherein increasing the young's modulus comprises increasing to a value exceeding 150 GPa.

32. The method of any of embodiments 28-31, wherein reducing the corresponding thickness increases the corresponding hardness values of the TiN film and the second TiN film.

33. The method of embodiment 32, wherein increasing the hardness value comprises increasing to a value exceeding 6 GPa.

34. The method of any of embodiments 28-33, wherein reducing the corresponding thickness reduces the corresponding chlorine content of the first and second TiN films.

35. The method of any of embodiments 25-34, wherein a ratio of the peak height or the intensity of the X-ray diffraction peak of the TiN film corresponding to the (111) crystal orientation of the TiN to the peak height or the intensity of the X-ray diffraction peak of the (200) crystal orientation of the TiN is higher than the ratio of the second TiN film.

36. The method of any of embodiments 25-35, wherein one or both of exposure to the first Ti precursor and the first N precursor during the one or more first periodic vapor deposition cycles is at a reactor pressure of less than about 5 torr, and wherein one or both of exposure to the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a reactor pressure of greater than about 5 torr.

37. A method of forming a thin film comprising titanium nitride (TiN) by a periodic vapor deposition process, the method comprising:

forming a first TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposing to a first Ti precursor at a first Ti precursor flow and exposing to a first N precursor at a first N precursor flow at a first pressure,

Wherein the first TiN film has a crystal texture such that an X-ray spectrum of the TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN of more than 0.4; and

a second TiN film is formed on the first TiN film by exposing the semiconductor substrate to one or more second periodic vapor deposition cycles each comprising exposing to a second Ti precursor at a second Ti precursor flow and exposing to a second N precursor at a second N precursor flow at a second pressure higher than the first pressure.

38. The method of embodiment 37, wherein the second pressure is greater than 5 torr.

39. The method of embodiment 37 or 38, wherein the second TiN film has a crystal texture such that an X-ray spectrum of the second TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystal orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystal orientation of TiN that is lower than the corresponding ratio of the first TiN film.

40. The method of any of embodiments 37-39, wherein at least a first ratio of the first N precursor flow to the first Ti precursor flow (first N/Ti flow ratio) is 3-100.

41. The method of embodiment 40, wherein a second ratio of the second N precursor flow to the second Ti precursor flow (second N/Ti flow ratio) is lower than the first N/Ti flow ratio.

42. The method of embodiment 41, wherein the method is such that increasing one or both of the first N/Ti flow ratio and the second N/Ti flow reduces the corresponding thickness of one or both of the first and second TiN films.

43. The method of embodiment 42 wherein reducing the corresponding thickness reduces the corresponding resistivity of the one or both of the first and second TiN films.

44. The method of embodiment 42 wherein reducing the corresponding thickness increases the corresponding young's modulus of the one or both of the first and second TiN films.

45. The method of embodiment 44, wherein increasing the young's modulus comprises increasing to a value exceeding 150 GPa.

46. The method of embodiment 42, wherein reducing the corresponding thickness increases the corresponding hardness value of the one or both of the first and second TiN films.

47. The method of embodiment 46, wherein increasing the hardness value comprises increasing to a value exceeding 6 GPa.

48. The method of embodiment 42, wherein reducing the corresponding thickness reduces the corresponding chlorine content of the first and second TiN films.

49. The method of embodiment 37, wherein the first pressure is less than 5 torr.

Although the application has been described herein with reference to particular embodiments, these embodiments are not intended to limit the application and are set forth for illustrative purposes. It will be apparent to those skilled in the art that modifications and improvements can be made without departing from the spirit and scope of the application.

Such simple modifications and improvements of the various embodiments disclosed herein are within the scope of the disclosed technology, and furthermore, the particular scope of the disclosed technology will be defined by the appended claims.

In the foregoing, it will be appreciated that any feature of any one of the embodiments may be combined with or substituted for any other feature of any other of the embodiments.

Throughout the specification and claims, unless the context clearly requires otherwise, the words "comprise", "comprising", "including", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; i.e., interpreted in the meaning of "including but not limited to". As generally used herein, the term "coupled" refers to two or more elements that may be connected directly or through one or more intervening elements. Likewise, as generally used herein, the term "connected" refers to two or more elements that can be connected directly or through one or more intervening elements. Furthermore, the words "herein," "hereinabove," "hereinafter," and words of similar import, when used in this disclosure, shall refer to this disclosure as a whole and not to any particular portions of this disclosure. Words in the above detailed description using the singular or plural number may also include the plural or singular number, respectively, where the context permits. The term "or" in relation to a list of two or more items encompasses all of the following term interpretations: any one of the items in the list, all of the items in the list, and any combination of the items in the list.

Moreover, unless explicitly stated otherwise or otherwise understood within the context as used, conditional language (such as, inter alia, "can," "possible," "can," "e.g., (e.g)," e.g., (for example), "such as (sush as)", etc.) as used herein is generally intended to convey that certain embodiments include and other embodiments do not include particular features, elements, and/or states. Thus, such conditional language is not generally intended to imply that one or more embodiments require features, elements and/or states in any way or whether such features, elements and/or states are included in or are to be implemented in any particular embodiment.

While certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms; moreover, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while features are presented in a given arrangement, alternative implementations may perform similar functionality with different components and/or sensor topologies, and some features may be deleted, moved, added, subdivided, combined, and/or modified. Each of these features can be implemented in a number of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The various features and processes described above may be implemented independently of one another or may be combined in various ways. All possible combinations and subcombinations of the features of the disclosure are intended to be within the scope of the disclosure.

Claims

2. The method of claim 1, wherein the N/Ti flow ratio is 3-100.

3. The method of claim 2, wherein the method is such that increasing the N/Ti flow ratio reduces the thickness of the TiN film.

4. The method of claim 3, wherein increasing the N/Ti flow ratio reduces the resistivity of the TiN film.

5. The method of claim 3, wherein the method is such that increasing the N/Ti flow ratio increases the young's modulus of the TiN film.

6. The method of claim 5, wherein increasing the young's modulus comprises increasing to a value exceeding 150 Gpa.

7. The method of claim 3, wherein the method is such that increasing the N/Ti flow ratio increases the hardness of the TiN film.

8. The method of claim 7, wherein increasing the hardness comprises increasing to a value exceeding 6 Gpa.

9. The method of claim 3, wherein increasing the N/Ti flow ratio reduces the chlorine content of the TiN film.

10. The method of claim 3, wherein the method is such that lowering deposition pressure increases a ratio of the peak height or the intensity of the X-ray diffraction peak corresponding to the (111) crystal orientation of the TiN to the peak height or the intensity of the X-ray diffraction peak corresponding to the (200) crystal orientation of the TiN.

11. A method according to claim 3, wherein the N precursor flow is 500sccm-10,000sccm.

12. A method according to claim 3, wherein the Ti precursor flow is 100sccm-5000sccm.

wherein the N precursor flow exceeds 500sccm, and

14. The method of claim 13, wherein the ratio of the N precursor flow to the Ti precursor flow (N/Ti flow ratio) is 3-100.

15. The method of claim 14, wherein the method is such that increasing the N/Ti flow ratio reduces the thickness of the TiN film.

16. The method of claim 15, wherein reducing the thickness reduces the resistivity of the TiN film.

17. The method of claim 15, wherein reducing the thickness increases the young's modulus of the TiN film.

18. The method of claim 17, wherein increasing the young's modulus comprises increasing to a value exceeding 150 Gpa.

19. The method of claim 15, wherein reducing the thickness increases the hardness of the TiN film.

20. The method of claim 19, wherein increasing the hardness comprises increasing to a value exceeding 6 Gpa.

21. The method of claim 15, wherein reducing the thickness reduces a chlorine content of the TiN film.

22. The method of claim 15, wherein the method is such that lowering deposition pressure increases a ratio of the peak height or the intensity of the X-ray diffraction peak corresponding to the (111) crystal orientation of the TiN to the peak height or the intensity of the X-ray diffraction peak corresponding to the (200) crystal orientation of the TiN.

23. The method of claim 15, wherein the N precursor flow is 500sccm-10,000sccm.

24. The method of claim 15, wherein the Ti precursor flow is 100sccm-5000sccm.

forming a first TiN film on a semiconductor substrate by exposing the semiconductor substrate to one or more first periodic vapor deposition cycles each comprising exposing to a first Ti precursor at a first Ti precursor flow and exposing to a first N precursor at a first N precursor flow; and

26. The method of claim 25, wherein exposure to one or both of the second Ti precursor and the second N precursor during the one or more second periodic vapor deposition cycles is at a higher pressure relative to corresponding exposure to one or both of the first Ti precursor and the first N precursor during the one or more first periodic vapor deposition cycles.

27. The method of claim 26, one or both of a first ratio of the first N precursor flow to the first Ti precursor flow (first N/Ti flow ratio) and a second ratio of the second N precursor flow to the second Ti precursor flow (second N/Ti flow) being 3-100.

28. The method of claim 27, wherein the method is such that increasing one or both of the first N/Ti flow ratio and the second N/Ti flow reduces the corresponding thickness of one or both of the first and second TiN films.

29. The method of claim 28, wherein reducing the corresponding thickness reduces the corresponding resistivity of the one or both of the first and second TiN films.

30. The method of claim 28, wherein reducing the corresponding thickness increases the corresponding young's modulus of the one or both of the first and second TiN films.

31. The method of claim 30, wherein increasing the young's modulus comprises increasing to a value exceeding 150 Gpa.

32. The method of claim 28, wherein reducing the corresponding thickness increases the corresponding hardness value of the one or both of the first and second TiN films.

33. The method of claim 32, wherein increasing the hardness value comprises increasing to a value exceeding 6 Gpa.

34. The method of claim 28, wherein reducing the corresponding thickness reduces the corresponding chlorine content of the first and second TiN films.

35. The method of claim 25, wherein a ratio of the peak height or the intensity of the X-ray diffraction peak of the first TiN film corresponding to the (111) crystal orientation of the TiN to the peak height or the intensity of the X-ray diffraction peak of the (200) crystal orientation of the TiN is higher than the ratio of the second TiN film.

36. The method of claim 25, wherein one or both of the first Ti precursor and the first N precursor are exposed to a first reactor pressure of less than about 5 torr during the one or more first periodic vapor deposition cycles, and wherein one or both of the second Ti precursor and the second N precursor are exposed to a reactor pressure of greater than about 5 torr during the one or more second periodic vapor deposition cycles.

38. The method of claim 37, wherein the second pressure is greater than 5 torr.

39. The method of claim 37, wherein the second TiN film has a preferential (111) crystalline texture such that an X-ray spectrum of the second TiN film has a ratio of a peak height or intensity of an X-ray diffraction peak corresponding to a (111) crystalline orientation of TiN to a peak height or intensity of an X-ray diffraction peak corresponding to a (200) crystalline orientation of TiN that is lower than the corresponding ratio of the first TiN film.

40. The method of claim 37, wherein at least a first ratio of the first N precursor flow to the first Ti precursor flow (first N/Ti flow ratio) is 3-100.

41. The method of claim 40, wherein a second ratio of the second N precursor flow to the second Ti precursor flow (second N/Ti flow ratio) is lower than the first N/Ti flow ratio.

42. The method of claim 41, wherein the method is such that increasing one or both of the first N/Ti flow ratio and the second N/Ti flow reduces the corresponding thickness of one or both of the first and second TiN films.

43. The method of claim 42, wherein reducing the corresponding thickness reduces the corresponding resistivity of the one or both of the first and second TiN films.

44. The method of claim 42, wherein reducing the corresponding thickness increases the corresponding young's modulus of the one or both of the first and second TiN films.

45. The method of claim 44 wherein increasing the Young's modulus comprises increasing to a value exceeding 150 GPa.

46. The method of claim 42, wherein decreasing the corresponding thickness increases the corresponding hardness value of the one or both of the first and second TiN films.

47. The method of claim 46, wherein increasing the hardness value comprises increasing to a value exceeding 6 GPa.

48. The method of claim 42, wherein reducing the corresponding thickness reduces the corresponding chlorine content of the first and second TiN films.

49. The method of claim 37, wherein the first pressure is less than 5 torr.