TW201215698A - Method of forming PZT thin film and method of manufacturing semiconductor device - Google Patents

Abstract

The present invention provides a method of forming a PZT thin film, which enhances a film composition distribution in a substrate plane, suppresses microscopic variations in the generation of crystal grains in the substrate plane, and enhances a surface roughness, and also provides a method for manufacturing a semiconductor device including this thin film. In the present invention, the organic metal compound raw material for Pb of one type selected from Pb(thd)2 and Pb(dmhd)2, organic metal compound raw material for Zr of one type selected from Zr(dmhd)4, Zr(thd)2(dmhd)2, Zr(thd)3(dmhd), Zr(i-PrO)2(thd)2, and Zr(i-PrO)(thd)3, and organic metal compound raw material for Ti of Ti(i-PrO)2(dmhd)2, are used as the respective organic metal compound raw materials for Pb, Zr, and Ti. The semiconductor device including this strong dielectric thin film is manufactured.

Description

201215698 VI. Description of the Invention: [Technical Field] The present invention relates to a method of forming a PZT thin film and a method of manufacturing a semiconductor device including the same. [Prior Art] In recent years, a ferroelectric thin film used as a ferroelectric memory such as a DRAM (Dynamic Random Access Memory) or a dielectric conductor filter has a perovskite structure. The thin film of lead zirconate titanate (Pb (Zrx, hereinafter referred to as PZT) is used because it exhibits a large residual polarization and a strong dielectric property. The formation of a ferroelectric film is a high-quality film with few defects, and is excellent in step cover age, and is also uniform in the surface of a large-diameter substrate. A method for producing a good PZT thin film with good reproducibility is reviewed for the Metal Organic Chemical Vapor Deposition (hereinafter referred to as MOCVD) method. This Μ CVD CVD method is In a CVD process in which a film material reacts at a high temperature and forms a film on a substrate, in particular, a method of using an organometallic compound as a raw material, and a gas for reacting an organometallic compound with a reactive gas (oxidizing gas or Reducing gas) and react by forming (for example) e.g., see Patent Document 1 and 2). In Patent Document 1, as a raw material, Pb(thd)2 and Zr(dmhd)4 and Ti(i-PrO)2(thd)2 are used, and the use of such organometallic compound raw material gas and concentration will be with time. In the case of Patent Document 2, Pb(CH3COO)2 · 3H20 and Zr(t-BuO)4 and Ti(i-PrO)4 are used for film formation. Film formation is carried out. Further, a method of producing an oxide film by supplying a mixed gas of a material gas, an oxidizing gas, and a diluent gas to a substrate and causing the reaction to form an oxide film is known (for example, refer to Patent Document 3). In Patent Document 3, as an organic metal compound raw material, Pb(thd)2 and Zr(dmhd)4 and Ti(i-PrO)2(thd)2 are used for film formation. Furthermore, it is also known to use from Pb(thd)2, Zr(thd)4, Zr(dmhd)4, Ti(i-Pr〇)2(thd)2, Zr(mmp)4, Ti(mmp)4 A method of forming a PZT thin film by a gas of a selected organometallic compound raw material and a reaction gas (for example, refer to Patent Document 4). Furthermore, it is known that a film forming apparatus which is useful for realizing the in-plane uniformity of a large-diameter substrate (for example, refer to Patent Document 5). In Patent Document 5, the in-plane uniformity is improved by optimizing the diameter of the shower plate or the distance between the shower plate and the substrate. Furthermore, a thin film manufacturing apparatus and a thin film manufacturing method which are useful for realizing a low number of particles in film formation are known (for example, refer to Patent Documents 6 and 7). In Patent Documents 6 and 7, Pb (dpm) 2, Zr (dmhd) 4 and Ti(i-PrO) 2 (dpm) 2 are used as the raw material of the organometallic compound, and oxygen is used as a reaction gas. Film formation was carried out with the number of particles. [PATENT DOCUMENT] [Patent Document 1] Japanese Patent Laid-Open Publication No. JP-A No. 2005-150787 [Patent Document 3] JP-A-2004-273787 (Patent Document 3) [Patent Document 5] Japanese Laid-Open Patent Publication No. 2004-35971 [Patent Document 6] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. [Invention of the Invention] In the prior art, in the technique of forming a PZT thin film by the MOCVD method, in order to form a high-quality film, it is used for a PZT thin film. The crystal orientation is controlled or the method of heating in advance when a film forming gas (mixed gas) is supplied. However, the control of the microscopic crystal structure is difficult, and the surface roughness is extremely large. Further, in consideration of the reproducibility of film formation, in order to make the reproducibility or composition distribution of the electrical characteristics of the obtained PZT thin film usable, for example, it is possible to spontaneously use information through a ferroelectric film. The level of the mass production of the FeRAM of the ferroelectric memory device for the memory of the polarization type is required to manage the reproducibility and distribution of the film composition of the PZT thin film to ±1% or less. Therefore, the development of the mass flow controller for controlling the flow rate of the material gas or the reaction gas or the fusion of the material gas is carried out. However, in the current situation, the reduction in the surface roughness of the obtained film and the reproducibility of electrical characteristics

S 201215698 From the point of view of the distribution of the membrane composition, it is still impossible to reach a sufficient level by flow control or fusion of raw material gases. That is, in the case of the above-described PZT thin film obtained by the prior art, the introduction amount of each metal at a specific film forming temperature is not necessarily stable, and is not sufficient to satisfy the film composition in the surface of the substrate. In the current distribution and film formation reproducibility, it is impossible to suppress variations in the microscopicity of occurrence of crystal grains in the surface of the substrate, and the surface roughness is also poor. The object of the present invention is to solve the above problems of the prior art and to provide a kind of stability in which the introduction amount of each metal at a specific film forming temperature is determined by a combination of specific organometallic compound raw materials. In addition, it is possible to increase the distribution of the film composition in the surface of the substrate, and to suppress the variation in the microscopicity of the occurrence of crystal grains in the surface of the substrate, and to further improve the surface roughness and the method for forming the PZT film. A method of manufacturing a semiconductor device comprising the thin film. [Means for Solving the Problem] The method for forming a PZT thin film of the present invention is a method for forming a PZT thin film on a substrate placed in a deposition chamber by MOCVD, and is characterized in that it is a metal of three types. : an organic metal compound raw material for Pb, Zr, and Ti, and an organometallic compound raw material for Pb selected from Pb(thd)2 and Pb(dmhd)2, and

Zr(dmhd)4, Zr(thd)2(dmhd)2, Zr(thd)3(dmhd), Zr(i-PrO)2(thd)2, and Zr(i-PrO)(thd)3 One of the Zr is an organometallic compound raw material, and Ti (i-Pr〇) 2 (dmhd) 2 is made of an organometallic compound of 201215698. By the combination of the above-mentioned general organometallic compound raw materials, the amount of introduction of each metal in the PZT thin film at a specific film forming temperature is constant, and the distribution of the film composition in the surface of the substrate and the film formation can be achieved. The improvement in the 'and' ability can suppress the deviation of the visibility of the occurrence of crystal grains in the surface of the substrate, and the surface roughness can be improved. Further, it is characterized in that, as the raw material of the respective organometallic compound for Pb and T i , for example, Pb(thd) 2 and Zr(i-PrO)(thd) 3 are obtained. And Τί(ί-ΡΓ〇)2(<ΐιηΙι<1)2. Further, it is characterized in that the respective organometallic compound raw materials for Pb, Zr and Ti are dissolved in tetrahydrofuran, n-butyl acetate, n-butyl acetate, and octane. In a solvent selected from cyclohexane and ethyl hexane, it is vaporized to act together with an oxidizing gas. Further, the temperature of the substrate is 560 to 620 ° C. If the substrate temperature is less than 56 (TC, the ratio of the amount of introduction of each of Pb, Zr, and Ti in the PZT film is difficult to be constant, and if it exceeds 6 2 〇 °c, there is a substrate, especially A tungsten plug (W Plug) which is often used in FeRAM is oxidized. It has the following characteristics: that is, a gas obtained by vaporizing a solution of the organic gold compound raw material, and After the oxidizing gas of the reaction gas is mixed, the mixed gas is supplied to the film forming chamber, whereby unevenness is generated and can be sufficiently generated on the substrate. Ding'an micro Zr is used for the fur ring Make the system thin in the genus

Further, S -9-201215698 has the feature that the pressure in the deposition chamber is set to 266.6 to 1333 Pa and film formation is performed. If the film formation is carried out at a pressure higher than 1333 Pa, the indoor residence time of the film forming gas increases, so that the film forming gas undergoes gas phase decomposition and causes abnormal grain growth, and the lower limit is The usual film formation pressure that can be used in p ZT film formation. In the method for fabricating a semiconductor device according to the present invention, the semiconductor device includes a PZT ferroelectric film, and a strong dielectric crystal is mainly used as a (1 1 1) alignment in the ferroelectric film. The manufacturing method is characterized in that the ferroelectric film is formed by a method of forming the PZT thin film described above, for example, as a ferroelectric film constituting a ferroelectric memory or the like, if used as The above-mentioned generally obtained PZT thin film is capable of realizing a useful magnet. [Effects of the Invention] According to the present invention, it is possible to obtain an effect that the distribution of the film composition of the PZT thin film in the surface of the substrate and the film reproducibility can be improved, and the substrate can be improved. The variation in the microscopicity of the occurrence of crystal grains in the plane is suppressed, and the increase in surface roughness can be achieved. Further, it is possible to achieve the general effect that an excellent memory effect can be provided in a semiconductor device including a ferroelectric memory or the like formed of such a PZT thin film. 201215698 [Embodiment] Hereinafter, embodiments of the present invention will be described. According to an embodiment of the PZT thin film formation method of the present invention, a method of forming a PZT thin film on a substrate placed in a deposition chamber by MOCVD is used as a metal of three types: Pb, Zr, and The respective organometallic compound raw materials for Ti are used: (a) from Pb(thd) 2 (bis(2,2,6,6-tetramethyl-3,5-heptanedionate) lead) and One of the selected organometallic compound materials for Pb selected from the group of (111111(1)2(lead of bis(2,6-dimethyl-3,5-heptanedionate)), preferably pb (thd)2; and (b) from 21&quot;((111111(1)4(tetrakis(2,6-dimethyl-3,5-heptanedionate) zirconium), Zr(thd)2(dmhd) 2 (bis(2,2,6,6-tetramethyl-3,5-heptanedionate) bis(2,6-dimethyl-3,5-heptanedionate) zirconium), zr (thd 3 (dmhd) (tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (2,6-dimethyl-3,5-heptanedionate) zirconium), Zr(i-PrO)2(thd)2((diisopropyloxy)bis(2,2,6,6-tetramethyl-3,5-heptanedionate) zirconium) and Zr(i-PrO) (thd) 3 ((diisopropoxy) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) chromium) selected from the group consisting of organic gold The compound material is preferably Zr(i-PrO)(thd)3; and (0)1'丨(1-?1*〇)2(£111111(1)2((diisopropoxy)bis( 2,6-Dimethyl-3,5-heptanedionate) Titanium is used as a raw material of an organometallic compound, and these pb, Zr and T1 are respectively dissolved in tetrahydrofuran using an organometallic compound raw material ( In a solvent selected from THF), butyl acetate, butyl acetate, octane, and cyclohexane, the gas is then vaporized, and the gas of the obtained organometallic compound raw material and oxygen gas such as oxygen are used. (Reaction gas) is supplied to the substrate s -11 - 201215698 which is placed in the film forming chamber at a specific flow rate, and is preferably "preferably" in the gas and oxidizing gas of the organometallic compound raw material. After mixing, the mixed gas is supplied to the film forming chamber, and is set to 266.6 to 1 3 3 3 Pa on a substrate set to a specific substrate temperature (preferably, 560 to 620 ° C). Under the pressure, a reaction is formed and a P-ZT film is formed. The device for forming the PZT ferroelectric thin film described above is not particularly limited. For example, it is only necessary to have a gasification device for vaporizing the respective organometallic compound raw materials for Pb, Zr, and Ti, and a pipeline having a raw material gas and an oxidizing gas to be introduced. It is sufficient to perform a vacuum controlled film forming chamber. For example, a film manufacturing apparatus described in Japanese Laid-Open Patent Publication No. 2005-054252 or JP-A-2005-05425 No. 2005-054252, and JP-A-2005-054253 The film production apparatus described in the present invention is a method in which a film forming gas is introduced into a reaction chamber through a shower head from an upper portion of a reaction chamber which is a reaction space of a vacuum chamber, and is heated by a substrate platform. a thin film manufacturing apparatus for forming a film on a substrate, wherein the upper reaction space is composed of a substrate platform, a shower head, and an anti-adhesion plate which are not rotated or lifted, and the anti-adhesion plate is used The concentric opening formed by the substrate platform is provided as a gas exhaust path, and is configured such that an inert gas flows along the anti-adhesion plate from above the gas exhaust path, and is in the gas exhaust path. The lower side is provided with a lower space, and the anti-adhesion plate is provided to be capable of transporting the substrate when the substrate is transported, and is capable of transporting the substrate and forming a reaction during film formation. The structure of the freely hoistable-12-201215698, the sprinkler head is configured to be temperature-controlled, and has a structure that is incorporated into the upper cover. The reaction is separated by the anti-adhesion plate. The outer side of the space is configured to be filled with an inert gas when the film is formed, and may be provided with a spray that is set to be placed in the upper cover via the substrate platform on which the substrate is placed. First, a vent gas is introduced into the exhaust gas line in the vacuum tank, and the exhaust gas line may be shared with a gas line for film formation connected to the shower head, where the exhaust gas is In the pipeline, a system for slow exhausting may be provided, and the surface of the shower head is formed by a disk-shaped shower plate, and a heat is disposed at a contact surface between the upper cover and the shower plate. The means of exchange, the temperature control of the shower plate, is carried out by heat exchange with the upper cover. The method for producing a semiconductor device including a PZT thin film according to the present invention is, for example, a ferroelectric memory obtained by a known method as a PZT ferroelectric film constituting the memory, and crystallizing It is mainly formed into a (111) alignment film by the above method. The present inventors have described the following in the following reference examples, and found that substrate-temperature dependence exists in the amount of introduction of the respective metals of Pb, Zr, and Ti into the PZT thin film, and in the present invention, A film formation is achieved by using a combination of the differential coefficients (temperature gradients) of the respective metals with respect to the substrate temperature to become equivalent biometal compound materials. According to the present invention, it is possible to obtain an effect that the distribution of the film composition of the PZT thin film in the surface of the substrate and the film reproducibility can be improved, and that the crystal grains in the surface of the substrate can be obtained. The deviation of the occurrence of microscopicity is suppressed, and the increase in surface roughness can be achieved. -13- 201215698 A description will be given of a method for selecting a general organometallic compound raw material in the present invention. In the combination of the organometallic compounds of each of Pb, Zr and Ti, changes in the amount of introduction of each metal into the film when the film formation temperature in the PZT film formation was changed were investigated. Here, the differential coefficient of the introduction amount of each metal of the mandarin to the actual film formation temperature with respect to the film formation temperature is compared. This differential coefficient is in the direction of being uniform with respect to the metals of Pb, Zr, and Ti, and is reviewed for replacement. It is known that before the film formation evaluation of an unknown raw material, the peak of the endothermic heat which can be known by the DT A (differential thermal analysis) method performed under certain conditions is read. It is desirable to suppress the decomposition temperature of the organometallic compound. It is desirable to compare and modulate the raw materials of the same metal in advance and to review and modulate whether they are easily decomposed with respect to temperature. First, in the combination of the organometallic compounds of each of Pb, Zr, and Ti, in the case where the film formation temperature in the PZT film formation is changed (500 to 620 ° C), the respective metals are in the film. The change in the amount of introduction is described by Comparative Example 1 and Example 1. <Comparative Example 1> As a raw material for PZT film formation, raw materials C: Pb(thd)2, Ti(i_PrO)2(thd)2, and Zr(dmhd)4, Zr(thd)2(dmhd)2, or Is Zr(thd)3(dmhd)' and each raw material is dissolved in THF, and the raw materials D: Pb(thd)2, Ti(i-PrO)2(thd)2, and Zr(i-PrO)2 are used ( Thd) 2, and dissolve the raw materials in the Xinyuan, and use the raw materials E: Pb(thd)2, -14- 201215698

Ti(i-PrO)2(thd)2 and Zr(i_Pr〇)(thd)3, and each raw material was dissolved in n-acetic acid butyl vinegar. Using the obtained solution of the organometallic compound raw material, each raw material solution was gasified at a gasification temperature of 220 to 25 ° C by a bulk material flow rate of about 0.6 mL/min, and obtained. The raw material gas is introduced into the deposition chamber through the shower plate, and is supplied to the substrate, and the oxygen gas is introduced into the 'one side at a specific substrate temperature (500 to 62 CTC). PZT is formed into a film. In this way, the relationship between the amount of introduction of each metal in the ρ ζ 膜 film and the substrate temperature (film formation temperature) due to the difference in the Zr raw materials was examined. The results are shown in Fig. 1 (a) to (e). In Fig. 1, the horizontal axis is the substrate temperature (Tsub; t), and the vertical axis is the normalized XRF intensity. Figures i(a), (b) and (c) show the case where Zr(dmhd)4, Zr(thd)2(dmhd)2, and Zr(thd)3(dmhd) are used as Zr raw materials, respectively. Figure i(d) shows the case where Zr(i-PrO)2(thd)2 is used as the Zr material, and Figure i(e) uses Zr (i - Pr as the Zr material). Ο) (thd) 3 case. As is apparent from Fig. 1 (a) to (e), Pb(thd) 2 is used as a Pb raw material, and Ti(i-Pr〇) 2(thd) 2 ' is used as a Ti raw material. Moreover, the type of Zr raw material has been changed, and the temperature dependence of the amount of introduction of the PZT film of each metal at a substrate temperature of 56 〇 to 620 ° C hardly changes. In either case, all the metals are When the slope is the same, and there is no such thing as the size of the same, the amount of introduction into the film of each metal does not become the same size. Therefore, it can be known that the composition distribution of each metal in the surface of the substrate does not become uniform. i -15-201215698 [Example 1] As a raw material for PZT film formation, raw materials F: Pb(thd) 2, Zr(i-PrO)(thd) 3, and Ti(i-PrO) 2 (thd) 2 were used. And the raw materials are dissolved in the acetic acid vinegar vinegar 'again, using the raw materials &lt;3: Pb. (thd'h, Zr.. (i.-.PrO.).. (th.d).3 and Ti ( i-PrO) 2 (dmhd) 2, and each raw material was dissolved in n-butyl acetate. Using the obtained solution of the organometallic compound raw material, each of the bulk raw material flow rates was about 0.6 mL/min. The raw material solution is vaporized at a vaporization temperature of 220 to 250 ° C, and the obtained raw material gas is introduced into the deposition chamber through a shower plate and supplied to the substrate at a specific substrate temperature (560 to 620). At ° C), PZT film formation was carried out while introducing oxygen gas at 3,500 sccm. Thus, for each metal due to the difference in Ti raw materials which are difficult to be introduced into the film at a low temperature The relationship between the amount of introduction in the film and the substrate temperature (film formation temperature) was examined. The results are shown in Fig. 2 (a) and (b). Further, the solutions of the above materials F and G were used, and In the same manner, the in-plane composition distribution of the PZT film formed by film formation at a substrate temperature of 620 ° C was measured by a fluorescent X-ray analyzer. The result is shown in Fig. 2 (cl). The case of the raw material F is shown, and the case of the raw material G is shown in Fig. 2 (c-2). In Fig. 2 (a) and (b), the horizontal axis is the substrate temperature (Tsub; °C), and the vertical axis The normalized XRF intensity is used, and Fig. 2(a) shows the case where the raw material F is used, and Fig. 2(b) shows the case where the raw material G is used. As shown in Fig. 2 (a) and (b) Obviously, in general, if the raw material F is compared with the case of the raw material G, the temperature dependence of the amount of introduction of each metal in the substrate at a substrate temperature of 560 to 6 2 0 X: In the case of the raw material g, 'all metals are consistent with the same slope, and from a lower temperature, exhibit a tendency to change to decrease. Therefore, it can be known that it is used in a higher temperature region. In the case of the combination of the raw materials G, it is possible to obtain a tendency that the slopes are uniform, and the amount of introduction into the ruthenium film of each metal is For the same size, the composition distribution of each metal in the substrate surface is uniform, and the composition distribution of each metal in the substrate surface is described with reference to FIGS. 2(cl) and (c-2). In each of (cl) and (c-2), the horizontal axis is a position (mm) from the center of the substrate, and the vertical axis is Pb/(Zr + Ti) and Zr/(Zr + Ti). As is apparent from Fig. 2 (cl) and (c-2), in the case of the raw material F, the film composition distribution of each metal in the surface of the substrate is Pb / (Zr + Ti) = ± 1.3. % and Zr / (Zr + Ti) = ± 2.6%, but not necessarily, but in the case of the raw material G, the film composition distribution of each metal in the surface of the substrate is Pb / (Zr + Ti) = ± 0.39% and Zr/(Zr + Ti) = ±0.30%, which is constant. As a result of summarizing the results shown in FIG. 1 and FIG. 2 above, it can be understood that the difference in the solvent for dissolving each organometallic compound hardly causes a difference in the amount of introduction of each metal film, and Even if Pb(thd)2 is used as a Pb raw material, Ti(i-Pr〇)2(thd)2 is used as a Ti raw material, and the kind of Zr raw material is changed at a substrate temperature of 560 to 620°. The temperature dependence of the amount of introduction of the film of each metal under C hardly changes, and in either case, all the metals become phases.

S -17- 201215698 has the same slope, and does not have the same size. The ratio of the amount of introduction of each metal film does not become the same. On the other hand, by using Ti (i-Pr〇h(dmhd) 2 ' with a low decomposition temperature as a Ti raw material, the temperature dependence of the amount of introduction into the film can be made at a substrate temperature of 560 to 620 ° C. The slope is the same as the ratio of the amount of introduction of the PZT film of each metal at a substrate temperature of 560 to 6200 ° C. Therefore, it can be known that in the obtained PZT film. The film composition distribution of each metal in the surface of the substrate is uniform. Therefore, Ti(i-PrO)2(dmhd)2 having a low decomposition temperature is used as the Ti raw material with respect to all of the above Zr raw materials. The thd group is an organometallic compound having a dmhd group, and the amount of introduction into the PZT film of all of ?1), 21*, and Ti can be set to the substrate temperature dependency of the same slope. Therefore, even when Pb (dmhd) 2 having a low decomposition temperature is used as the Pb raw material, it is possible to depend on the substrate temperature in which all of Pb, Zr, and Ti are introduced into the PZT film at the same slope. [Example 2] In this example, the surface morphology of the PZT film obtained by the method of the present invention was examined. As a raw material, Pb and Zr made of 0.3M-Pb(thd)2/THF, 0.3M-Zr(dmhd)4/THF, and 0.3M-Ti(i-PrO)2(thd)2/THF were used. And a solution of the raw materials of the respective organometallic compounds for Ti, and further, using 0.25 M-Pb(thd) 2 / n-butyl acetate, 〇 .25 M-Zr (i-PrO) 丨 (thd) 3 / positive B18-201215698 Butyl acrylate and Pb 'Z r of 25.25M-Ti(i-PrO)2(dmhd)2/n-butyl acetate, and raw materials of various organometallic compounds for T i The solution is vaporized by a volumetric raw material flow rate of about 0.6 m L/mi η at a gasification temperature of 22 〇 to 250 ° C, and the obtained raw material gas is introduced through a shower plate. In the film forming chamber, the film was supplied onto the substrate, and the PZT film was formed while introducing oxygen gas at 3,500 sccm under the conditions of a substrate temperature of 260 t: and a temperature rise time of 20 sec. . The surface morphology (surface roughness) of the PZT film thus obtained was observed by an SEM image, and the results are shown in Fig. 3. Further, the surface roughness was measured by AFM (Atomic Force Microscopy) and represented by Ra/P-V. Fig. 3 (a-1) shows the case where the above-mentioned Pb(thd)2, Zr(dmhd)4, and Ti(i-PrO)2(thd)2 are used as a raw material of an organometallic compound (process - A) The film formation state of the film surface, and the photographer is made obliquely from the upper side of the substrate, and Fig. 3 (a-2) shows the cross section of the substrate. Fig. 3 (b-1) is a case where the above-mentioned Pb(thd)2, Zr(i-PrO)i(thd)3, and Ti(i-PrO)2(dmhd)2 are used as a raw material of an organometallic compound. In the case (process-B), the film formation state of the film surface is obtained from the obliquely upper side of the substrate, and Fig. 3 (b-2) shows the cross section of the substrate. As can be seen from the comparison of Fig. 3 (al) and (a-2) with Figs. 3 (b1) and (b-2), the size of the mountain and valley of the film surface is in the process of the former - In the case of A, it is Ra/PV: 12.〇nm/95.7nm, and in the case of the latter process-B, it is Ra/PV: 5.4nm/4.〇nm -19- 201215698, and the latter In the case of Process-B, it is known that in the case of Process-B, the surface morphology is greatly improved. In addition, the number of processed wafers per hour (wf./hr) is 3.8 in the case of Process-A, and 4.0 in the case of Process-B. In the case of the process _B, the volume of the raw material enthalpy is set to about 15 mL/min ', and when the temperature rise time until the film formation temperature is shortened to 30 seconds (process-C), the ratio is 6.1, and the yield is 6.1. The system was improved. In the case of the above process -A, it is Pb / (Zr + Ti) = 1.177 and Zr / (Zr + Ti) = 0.450, and the PZT film thickness is l 〇 4 nm, in the case of the process - B, It is Pb / (Zr + Ti) = 1.179 and Zr / (Zr + Ti) = 0.457, and the PZT film thickness is 99 nm. [Example 3] In this example, the crystal orientation of a PZT ferroelectric thin film was examined. PZT ferroelectric thin film has residual partial enthalpy in the (〇〇1) direction and does not have residual partial enthalpy in the (1〇〇) direction, however, due to (001) and (1〇〇) The lattice length is slightly the same, so (100) will grow in the same place as (001), and the residual bipolar system will become smaller. In general, in the case where the alignment is (1 1 1), all of the crystals in the film can contribute to the polarization, and the residual polarization system becomes large. It can be seen that the PZT ferroelectric thin film which is oriented (111) is excellent in the polarization reversal fatigue property or the imprinting property which is an indicator of device reliability. Therefore, after reviewing the crystal orientation of the PZT film obtained in the case of Process-A, Process-B, and Process_C in Example 2, -20-201215698 3 showed the same PZT. (lll) alignment (Figure 4). In FIG. 4, in the case of Process-A and Process-B, the film thicknesses of Pb/(Zr + Ti), Zr/(Zr + Ti), and PZT are as described above, and in the case of Process-C. The ratio is Pb/(Zr + Ti)=1.177 and Zr/(Zr + Ti) = 0.444, and the PZT film thickness is 94 nm. [Embodiment 4] In this embodiment, the electrical characteristics of a PZT ferroelectric thin film were reviewed. As the electrical characteristics of the film obtained in Process A, Process-B, and Process-C in Example 2, the characteristics of the electric field with respect to the polarization amount were reviewed. The results are shown in Figure 5. As is apparent from Fig. 5, the PZT film obtained by the whole of the processes a to C exhibited the retention characteristics unique to the ferroelectric film and had strong dielectric properties. Further, in comparison with each process, when the electric field is 〇k V/cm, the sub-quantity (spontaneous polarization amount) is equal', and it is known that the electric dielectric properties are slightly equal. [Example 5] As a raw material for PZT film formation, 'Pb(dmhd)2; and Zr(thd)2(dmhd)2, zr(thd)3(dmhd), Zr(i-Pr0)2(thd)2 were used. One of them; and Ti(i-Pr〇) 2 (dmhdh, and each raw material is dissolved in n-butyl acetate. The obtained solution of each organometallic compound raw material is used according to the method described in Example 1 PZT film formation was carried out. With respect to the ruthenium film thus obtained, the ratio of the substrate temperature to the amount of introduction of the ρ ζ 膜 film of each metal was slightly the same, and the same as in the case of Example 1 The composition distribution of each metal in the surface of the substrate was uniform. Further, the surface roughness of the obtained ruthenium film was the same as that in the case of Example 2, and was the same as that of Example 3. 'There was a ΡΖΤ(111) alignment', and the 'electrical properties of Example 4' were also good. [Example 6] The method described in Example 1 was repeated. However, 'as the raw materials were dissolved The solvent, in place of n-butyl acetate, uses butyl acetate, octane, cyclohexane and ethylene The ratio of the substrate temperature of the ρττ film obtained in this manner to the amount of introduction into the ruthenium film of each metal is the same as that of the case of the first embodiment. The composition distribution of each metal in the surface of the substrate is uniform. [Industrial Applicability] According to the method for forming a ruthenium film according to the present invention, the amount of introduction of each metal at a specific film formation temperature is stable. In addition, the distribution of the film composition in the surface of the substrate and the film reproducibility can be improved, and the surface roughness can be improved by suppressing the variation in the microscopicity of the occurrence of crystal grains in the substrate surface. Therefore, the obtained film is useful as a ferroelectric film constituting a ferroelectric memory or the like, and can be used in the technical field of the semiconductor device industry. -22- 201215698 [Simple description of the drawing] [Fig. 1] The amount of introduction and the substrate temperature (film formation temperature) in the PZT film of each of the metals of Pb, Zr, and Ti due to the dissimilarity of the Zr raw materials obtained in Comparative Example 1. In the graph showing the relationship, (a), (b), and (c) ' are the case where the raw material c of the comparative example 1 is used, and (d) is the case where the raw material D of the comparative example 1 is used. (e) is the case where the raw material E of the comparative example 1 was used. [Fig. 2] is the metal of Pb, Zr, and Ti which are obtained by the difference of the raw material of the τ丨 obtained in Example 1. A graph showing the relationship between the amount of introduction in the PZT film and the substrate temperature (film formation temperature), (a) is the case where the raw material F of the first embodiment is used, and (b) is the raw material using the example 1. In the case of G, (c-1) is a graph showing the composition distribution of each metal in the surface of the substrate when the raw material F of Example 1 is used, (c-2) is implemented for use. In the case of the raw material g of Example 1, the composition distribution of each metal in the surface of the substrate is shown as a graph. 3 is a photograph showing an SEM image of a film obtained by performing PZT film formation according to Example 2, and (a-Ι) is a film surface in the case of Process-A of Example 2. In the film formation state, the photographer is photographed obliquely from the upper side of the substrate, (a-2) is a cross section showing the substrate, and (b-Ι) is a film in the case of the process-B of the second embodiment. The film formation state of the surface is taken from the obliquely upper side of the substrate, and (b-2) is the cross section of the substrate. Fig. 4 is a graph showing the crystal orientation of the film obtained in the case of the processes A, B and C according to Example 3.

I -23- 201215698 [Fig. 5] A graph showing the electrical characteristics of the film obtained in the case of Processes A, B, and C according to Example 4, and for electric field (kV/cm) and polarization (pC) The relationship between /cm2) is shown.

Claims (1)

201215698 VII. Patent Application Range: 1. A method for forming a PZT thin film, which is a method for forming a PZT thin film on a substrate placed in a film forming chamber by MOCVD, and is characterized by: as a metal of three types: An organic metal compound raw material for Pb selected from Pb(thd)2 and Pb(dmhd)2, and Zr(dmhd)4 are used as the raw material of the respective organometallic compound for Pb, Zr and Ti. , Zr(thd)2(dmhd)2, Zr(thd)3(dmhd), Zr(i-PrO)2(thd)2, and Zr(i_pr〇) (one of the selected ones of thdh) The raw material of the compound and the raw material of the organometallic compound for Ti of Ti(i_pr〇)2(dmhd)2. 2. The method for forming a ρζτ film as described in the first paragraph of the patent application 'where' is used as the aforementioned Pb, Zr and Ti For each of the organometallic compound raw materials', Pb(thd)2, Zr(i-PrO)(thd)3, and T i (i - P r 〇) 2 (dmhd) 2 are used. 3. As claimed The method for forming a PZT thin film according to the first or second aspect, wherein the raw material of the respective organometallic compound used for the Pb, Zr and Ti is dissolved in Tetrahydrofuran, butyl acetate, acetonitrile, octane, cyclohexane and ethylcyclohexane in a solvent selected and vaporized to be used together with an oxidizing gas. The method for forming a PZT thin film according to the first or second aspect, wherein the temperature of the substrate is 560 to 620 ° C. 5. The method for forming a PZT thin film as described in claim 3 of the patent application. The temperature of the substrate is 560 to 620 ° C. &amp; -25 - 201215698. The method for forming a PZT film according to the above or the second aspect of the invention, wherein the organic metal is The gas obtained by vaporizing the solution of the compound raw material is mixed with the oxidizing gas as a reaction gas, and then the mixed gas is supplied to the film forming chamber. 7. As described in the third paragraph of the profit-making scope A method for forming a film of the ruthenium ruthenium, wherein a gas obtained by vaporizing a solution of the organometallic compound raw material is mixed with an oxidizing gas as a reaction gas, and then the mixed gas is supplied to a film formation. 8. The method for forming a tantalum film according to the first or second aspect of the invention, wherein the pressure in the deposition chamber is set to 266.6 to 1333 Pa to form a film. In the manufacturing method, the semiconductor device is formed by including a PZT ferroelectric film, and in the ferroelectric film, the ferroelectric crystal is mainly used as the (1 1 1) alignment method, and the method is characterized. The method for forming a PZT thin film according to any one of the first to eighth aspects of the present invention is formed by the method of forming the ferroelectric film. -26-