Method for depositing molybdenum or tungsten materials

Abstract

A method is provided for rapidly depositing highly conformal molybdenum or tungsten-containing films on microelectronic device substrates under evaporation conditions. In the practice of the invention, the first nucleation step is performed while utilizing a lower overall concentration of metal precursor than is normally utilized in the reactor. The utilization of such a lower concentration of metal precursor can be achieved by adjusting the temperature of the ampoule (containing the precursor), the concentration of the precursor, the pressure in the reactor, and the duration of the pulse. In this manner, the utilization of a lower overall concentration results in the formation of a nucleation layer of about 3 Å or more, or up to about 9, 15, or 25 Å, at which time the conditions for introducing the precursor are advantageously modified and the concentration of the precursor in the reactor is increased for the purpose of bulk deposition.

Description

[Technical Field]

[0001] The present invention relates to the deposition of molybdenum or tungsten containing materials onto microelectronic substrates. [Background technology]

[0002] The properties of molybdenum and tungsten, such as very high melting points, low coefficients of thermal expansion, low resistivity, and high thermal conductivity, have led to their increasing use in the manufacture of semiconductor devices, including use in diffusion barriers, electrodes, photomasks, power electronics substrates, low resistivity gates, and interconnects.

[0003] Such utility has prompted efforts to achieve the deposition of molybdenum and tungsten films for these applications characterized by high conformality of the deposited films and high deposition rates suitable for efficient, high-volume manufacturing operations. This has inspired efforts to develop improved molybdenum and tungsten source reagents useful in vapor deposition operations, as well as improved process parameters utilizing such reagents. Furthermore, difficulties are often encountered in depositing molybdenum on certain substrates, such as metals, metal nitrides, dielectric materials (oxides), semiconductors, and superconductors, insofar as deposition delays can often be accompanied by difficulties in establishing nucleation on the substrate surface prior to the desired layer-on-layer deposition. As deposition temperatures decrease, the overall deposition rate typically decreases, and sensitivity to various substrate surfaces becomes more pronounced overall.

[0004] There remains a need to achieve deposition of molybdenum and tungsten-containing materials at higher deposition rates to accommodate efficient high volume manufacturing operations. Summary of the Invention

[0005] In certain embodiments, the present invention provides a method for rapidly depositing highly conformal metal-containing films, such as molybdenum- and tungsten-containing films, on microelectronic devices under evaporation conditions at low temperatures, i.e., below about 400°C, thereby enabling the deposition method to be used in a wide range of integration schemes, including the fabrication of logic devices. In the practice of the present invention, a first nucleation step is performed using a lower overall concentration of metal precursor than would normally be present in the reactor. The use of such a lower concentration can be achieved by adjusting the temperature of the ampoule (containing the precursor), the concentration of the precursor, the pressure within the reactor, and the pulse duration. This use of a lower overall concentration results in the formation of a nucleation layer of about 3 angstroms (Å) or greater, or up to about 9, 15, or 25 Å, at which point the conditions for introducing the precursor are advantageously modified and the concentration of the precursor within the reactor is increased (e.g., 50% higher than the concentration used for the nucleation step) for bulk deposition purposes. While in one embodiment, a molybdenum-containing film is deposited on a titanium nitride surface by utilizing a molybdenum precursor such as MoO2Cl2, it can be appreciated that the method has broader applicability for depositing molybdenum- or tungsten-containing films on surfaces where the formation of a metal nucleation layer is difficult (i.e., where overall nucleation delays are encountered), such as metals, metal nitrides, dielectric materials (oxides), semiconductors, and superconductors. [Brief explanation of the drawings]

[0006] [Figure 1] Scanning electron micrograph (SEM) of a formally exposed titanium nitride surface with a mass equivalent thickness of 1.6 Å of Mo prepared by chemical vapor deposition (CVD) of Mo using MoO2Cl2 as a precursor. The substrate temperature was 450°C. [Figure 2] SEM of a (comparative) example of chemical vapor deposition of molybdenum on titanium nitride using MoO2Cl2 at a substrate temperature of 400°C. This example showed poor nucleation with a mass-equivalent Mo thickness of 9.9 Å on the surface; only a molybdenum oxide phase was evident by X-ray diffraction. [Figure 3] 1 is an SEM showing the deposition / nucleation of molybdenum on a titanium nitride substrate using the method of the present invention (and a substrate temperature of 390° C.). The Mo film has a mass-equivalent thickness of 9.4 Å (see Example 1 below). [Figure 4] 10 is an SEM of a film prepared using nucleation process conditions with multiple cycles to produce a thin Mo film on a via structure that exhibits good film conformality. [Figure 5] SEM of a 104 Å mass-equivalent Mo film deposited on a PVD Mo substrate. CVD conditions were Tsub=390°C and a low precursor concentration of 30 ppm. This data indicates that the PVD Mo substrate is a comparable starting surface for the Mo nucleation step prior to bulk Mo deposition. [Figure 6] SEM of a 102 Å thick Mo film deposited by CVD on a TiN substrate. The deposition conditions were Tsub = 450°C and precursor concentration = 37 ppm, which is near the lower limit of the substrate temperature at which this concentration allows deposition of Mo on TiN. [Figure 7] SEM of a Mo film deposited on a TiN substrate in two steps. The Mo mass equivalent thickness is 108 Å. The deposition temperature was Tsub=390°C, and a low precursor concentration of 22 ppm was used for the pulsed CVD nucleation layer, while a 30 ppm precursor concentration was used for the bulk CVD deposition. The data show that the Mo nucleation step produces a starting surface suitable for bulk Mo deposition (comparable to PVD Mo substrates). [Figure 8] 1 is a plot of TiN etch in Å versus H flow rate (sccm). The data shows that increasing H flow rate decreases precursor concentration and illustrates how decreasing concentration during the nucleation step can decrease substrate (TiN) etching. [Figure 9]Comparison of CVD molybdenum deposition rates on titanium nitride and PVD molybdenum substrates as a function of deposition time. Substrate temperature = 650°C, pressure = 80 Torr, argon carrier gas flow rate = 50 sccm, hydrogen co-reactant gas flow rate = 4000 sccm. The graph shows the effect of nucleation delay on deposition rate. The graph also shows that the molybdenum deposition rate on titanium nitride over the period 300 to 600 seconds was increased by at least 25% when deposited on Mo compared to TiN substrates. Precursor concentration = 20 ppm. DETAILED DESCRIPTION OF THE INVENTION

[0007] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally utilized in its sense including "and / or" unless the context clearly dictates otherwise.

[0008] The term "about" generally refers to a range of numbers considered equivalent to a recited value (e.g., having the same function or result). In many instances, the term "about" may include numbers that are rounded to the nearest significant figure.

[0009] Numerical ranges expressed using endpoints include all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0010] Generally, the deposition method of the present invention involves the deposition of a metal nucleation layer of about 3 to about 25 Å as a first step. This first step is conveniently carried out using a relatively low concentration of precursor in the reactor compared to the concentration of precursor used subsequently, i.e., in the formation of the bulk film. Generally, utilizing a first low concentration of precursor to form the nucleation layer improves the overall processing time for ultimately depositing a film of the desired thickness, and surprisingly, this low concentration of precursor has been found to reduce the nucleation delay typically observed with molybdenum and tungsten precursors on certain substrates. In one embodiment, this relatively low concentration of precursor in the reactor is about 1 to about 75 mol %, or about 10 to about 50 mol %, of the concentration used in the bulk deposition step. All percentages and concentration recited herein are on a molar basis.

[0011] Accordingly, in a first aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device, the method comprising: introducing a molybdenum or tungsten precursor, the precursor having a first precursor concentration in the reaction zone, and a reducing gas, into a reaction zone containing the surface until a film having a thickness of from about 3 Å to about 25 Å is deposited; thereafter introducing a molybdenum or tungsten precursor, the precursor having a second precursor concentration in the reaction zone, and a reducing gas into the reaction zone until deposition of a molybdenum or tungsten-containing film having a desired thickness is achieved, wherein the first precursor concentration is from about 1 to about 75 percent of the second precursor concentration.

[0012] As will be appreciated by those skilled in the art, based on the present invention's recognition that a relatively low concentration of precursor is used in the first stage of deposition (to form the nucleation layer) followed by the second stage, which deposits the majority of the film, the present invention can be implemented in a variety of configurations, such as pulsing the precursor and sequentially introducing a reducing gas, sequentially introducing the precursor and sequentially introducing a reducing gas, and sequentially pulsing both the precursor and the reducing gas with or without an intervening purge step using an inert gas. Therefore, other permutations of these individual regimes can be envisioned, so long as the concentration in the first (nucleation) stage is relatively lower than the concentration used in the subsequent stage, in which the majority of the film is deposited on the microelectronic device surface. Furthermore, when selecting a particular precursor over another, those skilled in the art will first consider the vapor pressure of that precursor, and then, after considering the configuration and volume of the particular tool and associated reaction chambers used in the deposition method, will adjust the pressure, concentration, and flow rate of the particular precursor and / or any carrier gas used to achieve the desired precursor concentration in each of the two stages referred to herein.

[0013] In a second aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300°C to about 1000°C, the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. continuously introducing a reducing gas into a reaction zone including the surface while repeatedly introducing a molybdenum or tungsten precursor into the reaction zone, the precursor having a first concentration within the reaction zone at its peak of about 1 to about 5000 ppm in pulses of about 0.1 to about 120 seconds duration followed by a pause of about 1 to about 120 seconds, until a film having a thickness of about 3 Å to about 25 Å is deposited; and b. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface in pulses of about 0.1 to about 120 seconds duration to reach a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first precursor concentration, followed by a pause of about 1 to about 120 seconds while continuously introducing a reducing gas into the reaction zone, until a film having a desired thickness is deposited; The present invention provides a method comprising:

[0014] In a third aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300°C to about 1000°C, the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. continuously introducing a reducing gas into a reaction zone including the surface while continuously introducing a molybdenum or tungsten precursor into the reaction zone, the precursor having a first concentration within the reaction zone at its peak of about 1 to about 5000 ppm, until a film having a thickness of about 3 Å to about 25 Å is deposited; and b. continuously introducing a reducing gas into the reaction zone while continuously introducing a molybdenum or tungsten precursor into the reaction zone including the surface until a film having a desired thickness is deposited, thereby achieving a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first precursor concentration. The present invention provides a method comprising:

[0015] In a fourth aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300°C to about 1000°C, the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface for a first pulse duration of about 0.1 to about 120 seconds to reach a first concentration of the precursor in the reaction zone that is about 1 to about 5000 ppm, purging the reaction zone with an inert gas for about 1 to about 120 seconds, introducing a reducing gas into the reaction zone for a second pulse duration of about 0.1 to about 120 seconds, and purging with an inert gas for a duration of about 1 to about 120 seconds, until a film having a thickness of about 3 Å to about 25 Å is deposited; b. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface for a first pulse duration of about 0.1 to about 120 seconds to reach a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first concentration, purging the reaction zone with an inert gas for about 1 to about 120 seconds, and introducing a reducing gas into the reaction zone for a second pulse duration of about 0.1 to about 120 seconds and purging with an inert gas for a duration of about 1 to about 120 seconds until a film having a desired thickness is deposited; The present invention provides a method comprising:

[0016] Various alternative embodiments are contemplated for the first through fourth aspects of the present invention. In one embodiment, the concentration of precursor in the nucleation (i.e., first) stage is from about 1 to about 5000 ppm, from about 10 to about 2000 ppm, or from about 20 to about 500 ppm.

[0017] In another embodiment, the first precursor concentration is from about 10 to about 50 mole percent of the second precursor concentration.

[0018] In certain embodiments, the pressure maintained in the reaction zone is from about 1 to about 1000 torr, from about 20 to about 200 torr, or from about 40 to about 120 torr.

[0019] In certain embodiments, the temperature of the reaction zone is about 300 to 1000°C, about 325 to about 700°C, or about 350 to 500°C.

[0020] In one embodiment, the surface is selected from nitrides, oxides, metals, semiconductors, and superconductors. Specific examples include silicon, SiO2, Si3N4, OSG, FSG, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, photoresist, hard mask, carbon, germanium, germanium-containing, boron-containing, Ga / As, porous inorganic materials, metals such as copper and aluminum, and diffusion barrier layers such as, but not limited to, TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN. In another embodiment, the surface is titanium nitride.

[0021] In another embodiment, the molybdenum and tungsten precursors are selected from WCl6, WCl5, WOCl4, MoO2Cl2, MoCl5, and MoOCl4. In another embodiment, the precursor is MoO2Cl2.

[0022] In another embodiment, when pulsed introduction of precursor is utilized, the pulse "on" time is from about 0.1 seconds to about 120 seconds, from about 0.5 seconds to about 60 seconds, or from about 0.5 seconds to about 3 seconds. The pulse pause (i.e., "off" time) can be from about 1 second to about 120 seconds, from about 20 seconds to about 60 seconds, or from about 15 seconds to about 40 seconds.

[0023] As an example of the second embodiment, when depositing a molybdenum-containing film using MoO2Cl2 as a precursor, these predetermined levels of precursor concentration can be generated by introducing a predetermined amount of precursor into an ampoule, heating the ampoule to a predetermined temperature to fill the headspace with precursor vapor at a specific partial pressure, releasing the precursor vapor and carrier gas into the reaction zone, and then pausing the introduction of additional precursor. Throughout this first step, at least one reducing gas is continuously introduced into the reaction zone. During this pause, a carrier gas continues to flow into the ampoule, thereby increasing the pressure within the ampoule and effectively reducing the relative concentration within the ampoule. During this first step, the ampoule temperature can be maintained at, for example, about 40 to about 70°C, and the reaction zone temperature can be maintained at about 300 to about 1000°C, or about 325 to about 700°C, or about 350 to about 500°C. Generally, during such an example first step, the method is carried out so that the concentration of precursor in the reaction zone is from about 1 ppm to about 5000 ppm, which can be calculated as the partial pressure of the precursor vapor relative to the carrier gas, which can then be further diluted with the reducing gas and any other gases in the chamber.

[0024] Once this nucleation layer is complete, i.e., about 3 Å to about 25 Å, about 3 Å to about 15 Å, or about 3 Å to about 9 Å, bulk deposition of the molybdenum-containing film can be performed at a relatively higher concentration, i.e., about 1.3x to about 100x, compared to the nucleation step. Because the nucleation layer has been formed in the first step, bulk deposition can be performed much more quickly, utilizing higher concentrations of precursor vapor. This method is particularly advantageous for metal precursor / substrate combinations that tend to exhibit delayed nucleation, such as oxide and nitride substrates. In the second step, where bulk deposition of the metal-containing film occurs, introduction of precursor into the reactor can be continuous or pulsed in nature. Generally, during this bulk deposition phase, the concentration of precursor within the reactor is maintained at about 1.3x to about 100x when precursor flows continuously through the reactor. When the precursor is pulsed into the reactor, the concentration will vary from about 1 to about 5000 ppm depending on the flow rate at which the precursor is introduced into the reactor and the pulse duration. In any event, the concentration of precursor in the reactor during bulk deposition will be about 1.3x to about 100x the concentration utilized in the first (nucleation) step, and the concentrations listed during said pulse reflect the peak concentration achieved during said pulse.

[0025] The use of a carrier gas, and its flow rate, will ultimately depend on the configuration of the deposition tool, its scale of operation, and the particular precursors being utilized.

[0026] A minimum film thickness of about 3 Å for a continuous monolayer is observed. In one embodiment, deposition is continued until a thicker film is achieved, e.g., to obtain a continuous nucleation layer of about 6 Å, 9 Å, 15 Å, or 25 Å of the tungsten- or molybdenum-containing film, which allows for further vapor deposition, ultimately resulting in a tungsten- or molybdenum-containing film of the desired thickness. The molybdenum-containing film is highly conformal, and in one example, a resistivity of 37 μΩ-cm at a thickness of 39 Å was found. In one embodiment, the film exhibits a resistivity of about 10 to about 1000 μΩ-cm.

[0027] Thus, the bulk deposition referred to above can be utilized to provide the majority of film formation at a deposition rate of about 0.2 to about 2 Å per pulse cycle. Thus, while the use of the inventive techniques involving an initial, relatively low precursor concentration provides a high-quality, conformal nucleation layer, bulk deposition, whether in pulsed or continuous mode, can deposit a molybdenum- or tungsten-containing film layer by layer, resulting in the overall method more rapidly forming a desired final film thickness, e.g., about 25 Å to about 5 microns, all of which can be achieved using a single metal precursor at a constant, relatively high concentration in the reaction zone.

[0028] Furthermore, it has been found that minimal etching occurs in the practice of the present invention. See, for example, FIG. 4. When the nucleation layer is deposited at a low concentration, the substrate is only slightly etched and the film is deposited with a smooth surface profile. If the nucleation layer is continuous and the substrate is not subject to etching, the precursor vapor concentration can be increased. Increasing the precursor vapor concentration can increase the deposition rate and improve step coverage.

[0029] In the methods of the present invention, the precursor compounds may be reacted with the desired microelectronic device surface or substrate in any suitable manner, for example, in a single-wafer chamber, a multi-wafer chamber, or a furnace containing multiple wafers.

[0030] As used herein, the term "reducing gas" refers to a gas selected from hydrogen (H), diborane (BH), silane (SiH), and disilane (SiH). In certain cases, nitrogen-containing reducing gases such as ammonia (NH) and hydrazine (NH), and C1-C4 alkylhydrazines such as methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine, may be useful, although under some conditions, Mo or W nitride films will be obtained instead of pure metal films. Similarly, carbon-containing reducing gases such as alkanes, alkenes, and alkynes may be useful, although under some conditions, Mo or W carbide films will be obtained instead of pure metal films. In one embodiment, the reducing gas is hydrogen.

[0031] The methods disclosed herein may require one or more purge gases as an optional step between the introduction of the metal precursor and the introduction of the reducing and carrier gases. The purge or carrier gas is an inert gas that does not react with the precursors and is used to purge away unconsumed reactants and / or reaction byproducts or to act as a diluent and carrier for the metal precursor and reducing gas. Exemplary gases include, but are not limited to, argon, nitrogen, helium, neon, and mixtures thereof. In certain embodiments, a purge gas, such as Ar, is supplied into the reactor at a flow rate ranging from about 10 to about 10,000 sccm for about 0.1 to 1,000 seconds to purge unreacted materials and any byproducts that may remain in the reactor. Alternatively, such an inert gas may be utilized as a carrier gas to vary the concentration of the molybdenum or tungsten precursor and / or reducing gas used herein.

[0032] As used herein, the term "microelectronic device" corresponds to semiconductor substrates, including 3D NAND structures, logic devices, DRAM, power devices, flat panel displays, and microelectromechanical systems (MEMS), fabricated for use in microelectronics, integrated circuit, or computer chip applications. It is understood that the term "microelectronic device" is not intended to be limiting in any way and includes any substrate that comprises n-channel metal-oxide-semiconductor (nMOS) and / or p-channel metal-oxide-semiconductor (pMOS) transistors and ultimately becomes a microelectronic device or microelectronic assembly. Furthermore, the underlying substrate need not be silicon, but can be an insulator such as glass or sapphire, a high-bandgap semiconductor such as SiC or GaN, or other material useful in the fabrication of electrical circuits. Such microelectronic devices contain at least one substrate that can be selected from, for example, silicon, SiO2, Si3N4, OSG, FSG, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, boron nitride, antireflective coatings, photoresist, germanium, germanium-containing, boron-containing, Ga / As, flexible substrates, porous inorganic materials, metals such as copper and aluminum, and diffusion barrier layers such as, but not limited to, TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN. The films are compatible with various subsequent processing steps, such as, for example, chemical mechanical planarization (CMP) and anisotropic etching methods. [Example]

[0033] In the following examples, thickness values ​​refer to mass-equivalent thicknesses measured by X-ray fluorescence. This measurement technique measures the number of Mo atoms per unit area on the substrate with high precision. To convert this measurement to mass-equivalent thickness using a model of uniform film thickness, a thickness of approximately 10.28 g / cm is used. 3 Using the theoretical density of Mo metal, which is 0.05, it is understood that a poorly nucleated and highly rough film may be quite thick in some areas, but may have no thickness in other areas (bare substrate).

[0034] Example 1 Chemical vapor deposition was used with MoO2Cl2 at a TiN substrate temperature of 450 °C. The ampoule temperature was 40 °C, and the carrier gas flow rates were 25 sccm and 500 sccm H2, resulting in a concentration of 70 ppm at a pressure of 80 Torr. After 24 minutes, very little Mo was deposited (1.6 Å mass equivalent thickness), and the thin Mo film was too thin to measure resistivity. See Figure 1.

[0035] Example 2 Chemical vapor deposition was used with MoO2Cl2 at a TiN substrate temperature of 400°C. The ampoule temperature was 60°C, the carrier gas flow rate was 50 sccm, and H2 was 4000 sccm, resulting in a concentration of 20 ppm at a pressure of 80 Torr. After 10 minutes, a discontinuous 9.9 Å film with isolated nucleation sites was deposited, but the resistivity was not measurable. See Figure 2.

[0036] Example 3 Pulsed chemical vapor deposition was used with MoO2Cl2 at a TiN substrate temperature of 390 °C. The ampoule temperature was 40 °C, the carrier gas flow rate was 20 sccm, and H2 was 1000 sccm, resulting in a concentration of 22 ppm at a pressure of 80 Torr. After 20 cycles, a smooth 9.4 Å Mo film was produced with a resistivity of 222 μΩ-cm. See Figure 3. This example illustrates the overall lower concentration in the pulsed regime due to the "on" versus "off" pulse time and the dilution that occurs over time. Therefore, the concentration reached at the surface is not necessarily the concentration that remains on the surface and reacts with the reducing gas over time. Therefore, the effective concentration of precursor at the surface over time is lower in the pulsed CVD regime compared to the (continuous) CVD regime.

[0037] Example 4 Pulsed chemical vapor deposition was used with MoO2Cl2 at a SiN substrate temperature of 400°C. The ampoule temperature was 40°C, the carrier gas flow rate was 20 sccm, and H2 was 1000 sccm, resulting in a concentration of 22 ppm at a pressure of 80 Torr. After 200 cycles, a 125.3 Å film was obtained on the via structure. A good Mo film was obtained, with an AFM RMS roughness of 0.684 nm. See Figure 4.

[0038] Example 5 Chemical vapor deposition was used with MoO2Cl2 at a PVD Mo substrate temperature of 390°C. The ampoule temperature was 40°C, and the carrier gas flow rates were 20 sccm and 1000 sccm H2, resulting in a concentration of 30 ppm at a pressure of 80 Torr. After 20 minutes, a 104.4 Å Mo film was deposited on the 100 Å PVD Mo substrate. The resistivity of the CVD Mo film was 17 μΩ-cm. A good Mo film was produced, indicating a high deposition rate of CVD Mo on PVD Mo at a substrate temperature of 390°C. See Figure 5.

[0039] Example 6 Chemical vapor deposition was used with MoO2Cl2 at a TiN substrate temperature of 450°C. The ampoule temperature was 40°C, the carrier gas flow rate was 25 sccm, and H2 was 1000 sccm, resulting in a concentration of 37 ppm at a pressure of 80 Torr. After 20 minutes, a 101.9 Å film was deposited with a resistivity of 34.4 μΩ-cm. When the precursor concentration was reduced by a factor of 2 compared to Example 1, rough CVD Mo films could be deposited on TiN at a substrate temperature of 450°C. See Figure 6.

[0040] Example 7 A two-step chemical vapor deposition process was used with MoO2Cl2 at a TiN / Mo substrate temperature of 390°C. The ampoule temperature was 40°C, the carrier gas flow rates were 20 sccm, H2 was 1000 sccm, and the pressure was 80 Torr. In one experiment, the first step consisted of 45 cycles of pulsed CVD nucleation at a concentration of 22 ppm, depositing a 23.5 Å thick Mo layer on the TiN substrate. In a second experiment, the first step was repeated 45 times according to the above conditions. Immediately afterwards, the second step utilized a CVD process using the same conditions as the first step, except for a higher concentration of 30 ppm. After 20 minutes, the Mo film had a total thickness of 108 Å and a ρ of 17.7 μΩ-cm. Excellent Mo films were produced on TiN substrates, with resistivity and roughness comparable to those of CVD Mo films deposited directly on PVD Mo substrates. This resistivity is half that of the Mo film deposited without the low concentration nucleation layer of Example 6. See Figure 7 (for "Part B").

[0041] Pulsed CVD nucleation at 20 sccm, 10 min CVD bulk deposition (Mo), T sub The following comparative examples were produced using =390°C (substrate temperature), and H2 =1000 sccm. TIFF0007733133000001.tif57170As can be seen from this data, the nucleation stage of deposition stops between approximately 10 and 25 Å, as indicated by an increase in deposition rate of approximately 3 to 5.6 Å.

[0042] The table below provides AFM roughness data comparing Mo nucleation layer thicknesses of different thicknesses, Mo deposition without a nucleation layer, and a very thick nucleation layer. Varying the nucleation layer thickness has little effect on the roughness of the final Mo film, but has a significant effect on the bulk Mo deposition rate. TIFF0007733133000002.tif81170

[0043] Aspects In a first aspect, a method for depositing a molybdenum- or tungsten-containing film on a surface includes: introducing a first precursor and a reducing gas into a reaction zone containing the surface until a film having a thickness of about 3 Å to about 25 Å is deposited on the surface; and introducing a second precursor and a reducing gas into the reaction zone until deposition of a film having a desired thickness is achieved, wherein the concentration of the first precursor is about 1 to about 75 percent relative to the concentration of the second precursor in the reaction zone, and the first precursor and the second precursor can both be the same precursor or different precursors.

[0044] In a second aspect, the present invention provides the method of the first aspect, wherein the concentration of the first precursor is from about 10 to about 50 percent of the concentration of the second precursor.

[0045] In a third aspect, the present invention provides a method of the first or second aspect, wherein the surface is selected from a nitride, an oxide, a metal, a semiconductor, and a superconductor.

[0046] In a fourth aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300°C to about 1000°C, the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. continuously introducing a reducing gas into a reaction zone including the surface while repeatedly introducing a molybdenum or tungsten precursor into the reaction zone, the precursor having a first concentration within the reaction zone at its peak of about 1 to about 5000 ppm in pulses of about 0.1 to about 120 seconds duration followed by a pause of about 1 to about 120 seconds, until a film having a thickness of about 3 Å to about 25 Å is deposited; and b. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface in pulses of about 0.1 to about 120 seconds duration to reach a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first precursor concentration, followed by a pause of about 1 to about 120 seconds while continuously introducing a reducing gas into the reaction zone, until a film having a desired thickness is deposited; The present invention provides a method comprising:

[0047] In a fifth aspect, the present invention provides a method of the fourth aspect, wherein the precursor is selected from WCl6, WCl5, WOCl4, MoO2Cl2, MoCl5, and MoOCl4.

[0048] In a sixth aspect, the present invention provides a method of the fourth or fifth aspect, wherein the precursor is MoO2Cl2.

[0049] In a seventh aspect, the present invention provides the method of the fourth, fifth, or sixth aspect, wherein the pressure in the reaction zone is about 20 to about 200 Torr.

[0050] In an eighth aspect, the present invention provides the method of any one of the fourth to seventh aspects, wherein the first concentration of the precursor is from about 20 to about 500 ppm.

[0051] In a ninth aspect, the present invention provides the method of any one of the fourth to eighth aspects, wherein the temperature in the reaction zone is about 350 to 500°C.

[0052] In a tenth aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300° C. to about 1000° C., the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. continuously introducing a reducing gas into a reaction zone including the surface while continuously introducing a molybdenum or tungsten precursor into the reaction zone, the precursor having a first concentration within the reaction zone at its peak of about 1 to about 5000 ppm, until a film having a thickness of about 3 Å to about 25 Å is deposited; and b. continuously introducing a reducing gas into the reaction zone while continuously introducing a molybdenum or tungsten precursor into the reaction zone including the surface until a film having a desired thickness is deposited, thereby achieving a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first precursor concentration. The present invention provides a method comprising:

[0053] In an eleventh aspect, the present invention provides a method of the tenth aspect, wherein the precursor is selected from WCl6, WCl5, WOCl4, MoO2Cl2, MoCl5, and MoOCl4.

[0054] In a twelfth aspect, the present invention provides a method of the tenth or eleventh aspect, wherein the precursor is MoO2Cl2.

[0055] In a thirteenth aspect, the present invention provides the method of any one of the tenth to twelfth aspects, wherein the pressure in the reaction section is about 20 to about 200 Torr.

[0056] In a fourteenth aspect, the present invention provides the method of any one of the tenth to thirteenth aspects, wherein the first concentration of the precursor is from about 20 to about 500 ppm.

[0057] In a fifteenth aspect, the present invention provides the method of any one of the tenth to fourteenth aspects, wherein the temperature in the reaction zone is about 350 to 500°C.

[0058] In a sixteenth aspect, the present invention provides a method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300° C. to about 1000° C., the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface for a first pulse duration of about 0.1 to about 120 seconds to reach a first concentration of the precursor in the reaction zone that is about 1 to about 5000 ppm, purging the reaction zone with an inert gas for about 1 to about 120 seconds, introducing a reducing gas into the reaction zone for a second pulse duration of about 0.1 to about 120 seconds, and purging with an inert gas for a duration of about 1 to about 120 seconds, until a film having a thickness of about 3 Å to about 25 Å is deposited; b. repeatedly introducing a molybdenum or tungsten precursor into a reaction zone including the surface for a first pulse duration of about 0.1 to about 120 seconds to reach a second precursor concentration in the reaction zone that is about 1.3 to about 100 times the first concentration, purging the reaction zone with an inert gas for about 1 to about 120 seconds, and introducing a reducing gas into the reaction zone for a second pulse duration of about 0.1 to about 120 seconds and purging with an inert gas for a duration of about 1 to about 120 seconds until a film having a desired thickness is deposited; The present invention provides a method comprising:

[0059] In a seventeenth aspect, the present invention provides the method of the sixteenth aspect, wherein the precursor is selected from WCl6, WCl5, WOCl4, MoO2Cl2, MoCl5, and MoOCl4.

[0060] In an eighteenth aspect, the present invention provides a method of the sixteenth or seventeenth aspect, wherein the precursor is MoO2Cl2.

[0061] In a nineteenth aspect, the present invention provides the method of any one of the sixteenth to eighteenth aspects, wherein the pressure in the reaction section is about 20 to about 200 Torr.

[0062] In a twentieth aspect, the present invention provides the method of any one of the sixteenth to nineteenth aspects, wherein the first concentration of the precursor is from about 20 to about 500 ppm.

[0063] In a twenty-first aspect, the present invention provides the method of the twentieth aspect, wherein the temperature in the reaction zone is about 350 to 500°C.

[0064] Having thus described several exemplary embodiments of the present disclosure, those skilled in the art will readily recognize that still other embodiments may be made and used within the scope of the appended claims. The numerous advantages of the present disclosure, which are encompassed by this specification, are set forth in the foregoing description. It will be understood, however, that this disclosure is in many respects merely illustrative. The scope of the present disclosure will, of course, be defined in the language in which the appended claims are expressed.

Claims

1. 1. A method for depositing a molybdenum or tungsten-containing film on a surface, comprising: introducing a first precursor into the reaction zone including the surface in pulses of about 0.1 to about 120 seconds duration followed by a pause of about 1 to about 120 seconds, the first precursor having a first concentration within the reaction zone at its peak of about 1 to about 5000 ppm, while continuously introducing a reducing gas into the reaction zone including the surface, until a film having a thickness of about 3 Å to about 25 Å is deposited on the surface; introducing a second precursor and a reducing gas into the reaction zone until deposition of a film having a thickness of about 25 Å to about 5 microns is achieved, wherein the concentration of the first precursor is about 1 to about 75 percent relative to the concentration of the second precursor in the reaction zone, and the first precursor and the second precursor can both be the same precursor or different precursors; Including, the first precursor is contained in an ampoule before being introduced into the reaction zone, and the ampoule is maintained at a temperature of about 40 to about 70°C; The precursor is selected from WCl 6 , WCl 5 , WOCl 4 , MoO 2 Cl 2 , MoCl 5 , and MoOCl 4 ; method.

2. The method of claim 1, wherein the first precursor concentration is about 10 to about 50 percent of the second precursor concentration.

3. 1. A method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300° C. to about 1000° C., the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. while continuously introducing a reducing gas into a reaction zone including the surface, repeatedly introducing into the reaction zone in pulses of about 0.1 to about 120 seconds duration followed by a pause of about 1 to about 120 seconds a molybdenum or tungsten precursor, the precursor having a first concentration within the reaction zone of about 1 to about 5000 ppm at its peak, until a film having a thickness of about 3 Å to about 25 Å is deposited; b. While continuously introducing a reducing gas into the reaction zone including the surface, repeatedly introducing a molybdenum or tungsten precursor into the reaction zone in pulses of about 0.1 to about 120 seconds duration followed by a pause of about 1 to about 120 seconds until a film having a thickness of about 25 Å to about 5 microns is deposited, thereby achieving a second precursor concentration within the reaction zone that is about 1.3 to about 100 times the first precursor concentration. Including, The precursor is selected from WCl 6 , WCl 5 , WOCl 4 , MoO 2 Cl 2 , MoCl 5 , and MoOCl 4 ; method.

4. 1. A method for depositing a molybdenum or tungsten-containing film on a surface of a microelectronic device in a reactor, the reactor being operated at a pressure of about 1 to about 1000 Torr and a temperature of about 300° C. to about 1000° C., the surface being selected from nitrides, oxides, metals, semiconductors, and superconductors, the method comprising: a. continuously introducing a molybdenum or tungsten precursor into the reaction zone, the precursor having a first concentration within the reaction zone of about 1 to about 5000 ppm at its peak, while continuously introducing a reducing gas into the reaction zone including the surface, until a film having a thickness of about 3 Å to about 25 Å is deposited; b. continuously introducing a molybdenum or tungsten precursor into the reaction zone, including the surface, while continuously introducing a reducing gas into the reaction zone until a film having a thickness of about 25 Å to about 5 microns is deposited, thereby achieving a second precursor concentration within the reaction zone that is about 1.3 to about 100 times the first precursor concentration. Including, The precursor is selected from WCl 6 , WCl 5 , WOCl 4 , MoO 2 Cl 2 , MoCl 5 , and MoOCl 4 ; method.

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