JP2006054382A - Metallic silicate film, manufacturing method thereof, semiconductor device, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a current leakage pass and to improve capacitor capacity Cs by devising the distribution of silicon and a metal in the film thickness direction of a metallic silicate film to be used for a capacity insulating film of the capacitor. <P>SOLUTION: On the interface side of the metallic silicate film 101 as compared with the inner side of the film 101 in the film thickness direction of the film 101, the composition ratio of silicon constituting the film 101 is higher than that of the metal, and on the inner side of the film 101 as compared with the interface side of the film 101 in the film thickness direction, the composition ratio of the metal constituting the film 101 is higher than that of silicon. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal silicate film in which a hafnium silicate film in which the composition ratio of hafnium and the composition ratio of silicon are changed in the film thickness direction can be easily formed, a method for manufacturing the metal silicate film, and a semiconductor device and a semiconductor using the film The present invention relates to a device manufacturing method.

  In a semiconductor device, particularly a semiconductor memory device, a capacitor is used as information storage and holding means. Capacitor memory types are classified into volatile and non-volatile, and volatile memory includes DRAM (Dynamic Random Access Memory) and SRAM (Static RAM), and non-volatile memory includes FeRAM (Ferroelectric RAM) and MRAM (Magnetic). RAM) is known.

  For example, a DRAM has a memory cell structure including a capacitor memory and a switching field effect transistor (MOSFET). In recent years, further miniaturization and higher integration and an increase in capacity of a capacitor memory have been promoted. In order for a capacitor to sufficiently perform a memory cell function in a miniaturized and highly integrated semiconductor device, it is necessary to secure a storage capacity (Cs) of about 25 fF to 40 fF per bit.

However, as the semiconductor device is miniaturized and highly integrated, the area occupied by the capacitor in the unit memory cell is decreasing. This means that the storage capacity of the capacitor is also reduced. Therefore, in a miniaturized and highly integrated semiconductor device, in order to increase the storage capacity of a capacitor incorporated therein, a deep trench (DT) shape is used, and a capacitor insulating film is made more than SiO or SiON. The use of a high dielectric constant (High-k) material such as a metal oxide film (HfO ₂ , Al ₂ O ₃ , ZrO _2, etc.) or a metal silicate film (HfSiO ₂ ) having a high relative dielectric constant has been proposed.

Although the metal oxide film generally has a high relative dielectric constant, the film is crystallized by heat treatment after film formation, and when used as a capacitor insulating film, the leakage current increases through the crystal grain boundary. There was a problem that heat resistance deteriorated (HfO ₂ has a heat resistance of approximately 700 ° C.). In contrast, a metal silicate film has a relative dielectric constant smaller than that of a metal oxide film, but since it contains silicon oxide, it is thermally stable and has a higher crystallization temperature than a film of a metal oxide alone. (For example, refer to Patent Document 1).

JP 2003-318174 A

  The problem to be solved is that since heat resistance is low, crystallization occurs due to heat treatment, and when used as a capacitor insulating film, the leakage current increases through the crystal grain boundary, and also has high heat resistance. In the conventional metal silicate film, the relative dielectric constant is greatly reduced.

  In the metal silicate film of the present invention, in the film thickness direction of the metal silicate film, the composition ratio of silicon constituting the metal silicate film is higher than the metal composition ratio on the interface side of the film from the inner side of the film. The main feature is that the composition ratio of the metal constituting the metal silicate film is higher than the composition ratio of silicon in the film thickness direction of the silicate film from the interface side to the inside of the film.

  In the metal silicate film manufacturing method of the present invention, the composition ratio of silicon constituting the metal silicate film is higher than the metal composition ratio in the film thickness direction of the metal silicate film on the interface side of the film from the inner side of the film. A metal silicate film manufacturing method in which the composition ratio of the metal constituting the metal silicate film is higher than the composition ratio of silicon on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. The metal silicate film is formed by forming a layer of silicon atoms and a step of forming a layer of oxygen atoms on the layer of silicon atoms and forming a layer of metal atoms and forming oxygen atoms on the layer of metal atoms. Performing at least one of the steps of forming a layer is one cycle of film formation, and in the film formation step of forming the interface side of the metal silicate film, one cycle of film formation is Forming a group of silicon atoms and forming a layer of oxygen atoms on the layer of silicon atoms and forming a layer of oxygen atoms more than the step of forming a layer of oxygen atoms on the layer of metal atoms and forming a layer of oxygen atoms on the layer of metal atoms; In the film forming step of forming the inner side of the metal silicate film, the one cycle of the film forming includes forming a layer of silicon atoms from the step of forming a layer of metal atoms and a layer of oxygen atoms on the layer of metal atoms. In addition to the formation of the oxygen atom layer on the silicon atom layer, the composition ratio of the metal silicate film is determined every cycle of the film formation or after repeating the film formation cycle a predetermined number of times. In the determination, if the composition ratio and the film thickness of the metal silicate film are within a desired range, the film formation is terminated. ,Money When the composition ratio of the silicate film and the film thickness deviates from the desired range and most important feature to perform again one cycle of the film forming.

  The semiconductor device of the present invention is a semiconductor device including a capacitor having a metal silicate film sandwiched between electrodes, and the metal silicate film is closer to the interface of the film than the center of the film in the thickness direction of the metal silicate film. The composition ratio of silicon constituting the metal silicate film is higher than the composition ratio of the metal, and the metal silicate film is formed on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. The main feature is that the composition ratio is higher than that of silicon.

  A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device having a capacitor having a metal silicate film sandwiched between electrodes, wherein the forming step of the metal silicate film forms a silicon atom layer and silicon The step of forming the oxygen atom layer on the atomic layer and the step of forming the metal atom layer and the step of forming the oxygen atom layer on the metal atom layer are performed at least once. In the film formation step of forming a cycle and forming the interface side of the metal silicate film, one cycle of the film formation is more silicon than the step of forming a metal atom layer and an oxygen atom layer on the metal atom layer. In addition to forming an atomic layer, many steps of forming an oxygen atom layer on the silicon atom layer are performed. In the film forming step of forming the inner side of the metal silicate film, one of the film formation steps is performed. Iccle has more steps to form a silicon atom layer and a silicon atom layer than to form a metal atom layer on the metal atom layer and to form a silicon atom layer on the silicon atom layer. Performing the step of determining whether the composition ratio and the film thickness of the metal silicate film are within a desired range every cycle of the film formation or after repeating the film formation cycle a predetermined number of times, In the determination, when the composition ratio and the film thickness of the metal silicate film are within a desired range, the film formation is terminated, and when the composition ratio and the film thickness of the metal silicate film are out of the desired range in the determination. In this case, the composition ratio of silicon constituting the metal silicate film is compared with the composition ratio of the metal in the film thickness direction of the metal silicate film from the inner side of the film to the interface side of the film by performing one cycle of the film formation again. do it And forming a metal silicate film having a higher composition ratio of the metal constituting the metal silicate film than the composition ratio of silicon on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. The most important feature.

In the metal silicate film of the present invention, the composition ratio of silicon constituting the metal silicate film is higher in the film thickness direction of the metal silicate film than the inner side of the film, compared with the composition ratio of the metal. Since the metal silicate film is close to a silicon (SiO ₂ ) film, the reaction between the Si interface and the metal is suppressed, and crystallization that becomes a leak path can be prevented. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, capacitor leakage can be reduced. Further, since the metal silicate film is close to SiO ₂ , the heat resistance is improved. On the other hand, since the composition ratio of the metal constituting the metal silicate film is higher than the composition ratio of silicon in the film thickness direction of the metal silicate film from the interface side of the film to the inner side of the film, the metal silicate close to the metal oxide film Since it is a film, the relative permittivity can be further increased. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, there is an advantage that the capacitance Cs can be increased.

The method for producing a metal silicate film of the present invention includes a step of forming a layer of silicon atoms and forming a layer of oxygen atoms on the layer of silicon atoms, and forming a layer of metal atoms and oxygen atoms on the layer of metal atoms. For example, in the film formation process for forming the interface side of the metal silicate film, one cycle of film formation is performed at least once at least once. , Forming a layer of silicon atoms and forming a layer of oxygen atoms on the silicon atom layer more than forming a layer of oxygen atoms on the metal atom layer and forming a layer of oxygen atoms on the metal atom layer; Thus, a metal silicate film close to silicon oxide (SiO ₂ ) can be formed. As a result, the reaction between the Si interface and the metal is suppressed, and crystallization as a leak path can be prevented. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, capacitor leakage can be reduced. Further, since the metal silicate film is close to SiO ₂ , the heat resistance is improved. On the other hand, in the film formation process for forming the inner side of the metal silicate film, one cycle of film formation is a layer of silicon atoms compared to the process of forming a metal atom layer and forming an oxygen atom layer on the metal atom layer. In addition, by performing many steps of forming an oxygen atom layer on the silicon atom layer, a metal silicate film close to the metal oxide film can be formed. This makes it possible to increase the relative dielectric constant. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, there is an advantage that the capacitance Cs can be increased. Further, by determining whether the composition ratio and the film thickness of the metal silicate film are within a desired range for each cycle of film formation, the desired film thickness, the desired metal composition ratio, and the silicon composition ratio are adjusted. It becomes possible to control the metal silicate film composition at each step.

  Since the semiconductor device of the present invention uses the metal silicate film of the present invention as an insulating film of a capacitor, the reaction between the Si interface and the metal is suppressed, and crystallization as a leak path can be prevented, thereby reducing the capacitor leak. There is an advantage that can be made. Further, since the relative dielectric constant of the metal silicate film can be increased, there is an advantage that the capacitance Cs can be increased.

Since the semiconductor device manufacturing method of the present invention forms the insulating film of the capacitor by the metal silicate film manufacturing method of the present invention, in the film forming step of forming the interface side of the metal silicate film, one cycle of film formation is , Forming the silicon atom layer and forming the oxygen atom layer on the silicon atom layer more than forming the metal atom layer and forming the oxygen atom layer on the metal atom layer. Thus, a metal silicate film close to silicon oxide (SiO ₂ ) can be formed. As a result, the reaction between the substrate interface and the metal is suppressed, and crystallization as a leak path can be prevented. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, capacitor leakage can be reduced. Further, since the metal silicate film is close to silicon oxide (SiO ₂ ), the heat resistance is also improved. On the other hand, in the film forming step for forming the inner side of the metal silicate film, one cycle of film forming includes forming a layer of metal atoms and a step of forming a layer of oxygen atoms on the layer of metal atoms. In addition, the metal silicate film close to the metal oxide film can be formed by performing more than the step of forming the oxygen atom layer on the silicon atom layer. This makes it possible to increase the relative dielectric constant. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, there is an advantage that the capacitance Cs can be increased. Further, by determining whether the composition ratio and the film thickness of the metal silicate film are within a desired range for each cycle of film formation, the desired film thickness, the desired metal composition ratio, and the silicon composition ratio are adjusted. It becomes possible to control the metal silicate film composition at each step.

  The purpose of obtaining a metal silicate film having a dielectric constant higher than that of a conventional silicon oxide-based capacitor insulating film, as well as preventing leakage crystallization by having heat resistance, is a film of a hafnium silicate film. This was achieved by adjusting the composition ratio of hafnium and silicon in the thickness direction.

  One embodiment of the metal silicate film of the present invention will be described with reference to the relationship diagram of composition ratio and film thickness in FIG.

  As shown in FIG. 1, the metal silicate film 101 is made of, for example, a hafnium silicate film, and the composition ratio of hafnium constituting the hafnium silicate film is higher on the interface side of the film than the center of the film in the film thickness direction. The composition ratio of silicon constituting the silicate film is lowered.

  On the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. It is less than 100%. On the inner side of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is 30% to less than 100%, and the composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and less than 70%. is there.

  On the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. Since the composition is less than 100%, the interface side has a composition close to that of silicon oxide, so that the heat resistance is high, and crystallization hardly occurs by heat treatment. As a result, a crystal grain boundary that becomes a leakage path is less likely to occur, so that when the metal silicate film is used as a capacitor insulating film, the problem of the prior art that the leakage current increases through the crystal grain boundary is solved. The

  On the other hand, on the inner side of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%, and the composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and 70%. Since the inner side has a composition close to that of hafnium oxide, it is possible to suppress a decrease in relative dielectric constant as a metal silicate film.

  The metal silicate film 101 is preferably heat-treated in an atmosphere containing nitrogen. By such nitriding treatment, a film containing nitrogen is obtained, and the heat resistance is further improved.

The metal silicate film of the present invention is a metal silicate film close to SiO ₂ because the composition ratio of silicon constituting the interface side (front and back sides) is higher than the composition ratio of hafnium. Reaction with (hafnium) is suppressed, and crystallization as a leak path can be prevented. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, capacitor leakage can be reduced. Further, since the metal silicate film is close to SiO ₂ , the heat resistance is improved. On the other hand, since the composition ratio of the metal (hafnium) constituting the metal silicate film is higher than the composition ratio of silicon in the film thickness direction of the metal silicate film from the interface side of the film to the inner side of the film, the metal oxide film ( For example, when the metal is hafnium, it becomes a metal silicate film close to HfO ₂ ), so that the relative dielectric constant can be further increased. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, there is an advantage that the capacitance Cs can be increased.

  Next, an embodiment of the semiconductor device according to the present invention will be described with reference to a schematic sectional view of FIG. 2 and a circuit diagram of FIG.

  As shown in FIG. 2A, the semiconductor device of the present invention includes a capacitor having a high dielectric film made of a metal silicate film 101 between electrodes 111 and 112, and the configuration of the capacitor is as follows. For example, it can be applied to a trench capacitor 200 as shown in FIG. That is, along the surface of the trench 202 formed in the semiconductor substrate (for example, silicon substrate) 201, the first electrode 211 formed by diffusing impurities is formed in the semiconductor substrate 201. On the surface of the trench 202, the metal silicate film 101 is formed as a capacitor insulating film. The second electrode 212 is formed of, for example, a conductive film so as to fill the trench 202. As this conductive film, for example, a polysilicon film into which impurities are introduced can be used. As each impurity, for example, an n-type impurity or a p-type impurity used in a diffusion layer of a general semiconductor device can be used.

As the metal silicate film 101, for example, the hafnium silicate film described in the first embodiment can be used, and the silicon constituting the hafnium silicate film is closer to the interface of the film than the center of the film in the film thickness direction of the hafnium silicate film. The composition ratio of hafnium is higher than the composition ratio of hafnium, and the composition ratio of hafnium constituting the hafnium silicate film is compared with the composition ratio of silicon in the film thickness direction of the hafnium silicate film from the interface side to the inside of the film. And expensive. That is, a hafnium silicate film close to silicon oxide (SiO ₂ ) is formed on the interface side of the film, and a hafnium silicate film close to hafnium oxide (HfO ₂ ) is formed on the inner side of the film.

In the hafnium silicate film, the composition ratio of hafnium to silicon in the film is greater than 0% and not more than 30% on the interface side, and the composition ratio of silicon to hafnium in the film is not less than 70% and less than 100%. As a result, a hafnium silicate film close to silicon oxide (SiO ₂ ) is formed on the interface side, heat resistance is improved, and crystallization of the hafnium silicate on the inner side can be prevented. Note that when the amount of silicon is reduced from the above range and the amount of hafnium is increased, the properties of silicon oxide are reduced, so that the heat resistance is lowered and it is difficult to prevent crystallization of the internal hafnium silicate. Arise. On the other hand, on the inner side of the hafnium silicate film, the composition ratio of hafnium to silicon in the film is 30% or more and less than 100%, and the composition ratio of silicon to hafnium in the film is greater than 0% and 70% or less. As a result, a hafnium silicate film close to HfO ₂ is formed on the inner side, and a higher dielectric constant can be obtained than ordinary hafnium silicate. If hafnium is reduced from the above range and silicon is increased, the property of HfO ₂ is reduced, which causes a disadvantage that the dielectric constant is lowered.

  The trench capacitor 200 can be applied to a memory cell of a dynamic random access memory (DRAM) as shown in FIG. The memory cell 300 includes one MOS transistor 310 and one capacitor 320, and the trench capacitor 200 can be applied to the capacitor 320.

  Since the semiconductor device (memory cell 300) of the present invention uses the metal silicate film 101 of the present invention as a capacitor insulating film, the silicon interface of the semiconductor substrate 201, the silicon interface of the second electrode 212, and the metal silicate film 101 Since the reaction with the metal (hafnium) is suppressed and crystallization as a leak path can be prevented, there is an advantage that the capacitor leak can be reduced. Further, since the relative dielectric constant of the metal silicate film 101 can be increased, there is an advantage that the capacitance Cs can be increased.

  One embodiment of the method for forming a metal silicate film of the present invention will be described with reference to the flowchart of FIG.

As shown in FIG. 4, first, a pretreatment (for example, cleaning) of the deposition surface of the substrate (for example, a silicon substrate) 11 is performed by “pretreatment” S1. The substrate is not limited to a silicon substrate, and various substrates such as an insulating substrate such as a glass substrate, a quartz substrate, and a ceramic substrate, and a semiconductor substrate such as a silicon substrate and a compound semiconductor substrate can also be used. In the case where the substrate is a silicon substrate, the above-mentioned “pretreatment” is performed after cleaning in a range of 20 to 60 seconds with dilute hydrofluoric acid in order to remove a natural oxide film on the substrate, for example, in an ammonia (NH ₃ ) gas atmosphere. Heat treatment is performed in the range of 600 ° C. to 1000 ° C. to nitride the silicon substrate surface.

  Next, as the “Si—O cycle” S2, a layer of silicon atoms is formed and an oxygen atom layer is formed on the silicon atom layer. This layer formation uses an atomic layer deposition method (generally referred to as an ALD (Atomic Layer Deposition) method) (not shown).

The “Si—O cycle” S2 will be described in detail. First, the substrate subjected to the above pretreatment is housed in a film forming chamber of an ALD apparatus, and the substrate is heated and held at, for example, 250 ° C. to 400 ° C. Then, the process of “supplying Si precursor gas” S21 is performed. In this step, silicon (Si) precursor gas is supplied onto the substrate and adsorbed on the substrate surface. As the Si precursor gas, for example, Si [N (CH ₃ ) (C ₂ H ₅ )] ₄ or [SiH (CH ₃ ) ₂ ] ₂₀ can be used.

  Next, the “purging with an inert gas” step S22 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

Next, the process of “supply of oxygen-containing material” S23 is performed. In this step, ozone (O ₃ ) or water (H ₂ O) is supplied to the substrate surface to form an oxygen (O) atom layer on the silicon (Si) atom layer.

  Next, the “purging with inert gas” step S24 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

  The above is the “Si—O cycle” S2 in which a layer of oxygen (O) atoms is formed on a layer of silicon (Si) atoms.

  Next, a “metal-O cycle” S3 is performed in which a layer of metal (eg, hafnium) atoms is formed and an oxygen atom layer is formed on the layer of metal (eg, hafnium) atoms. Hereinafter, the metal will be described using hafnium as an example. In addition, this layer formation is performed by the atomic layer deposition method subsequent to the “Si—O cycle”, and the film formation is performed in-situ following the “Si—O cycle” S2.

The “metal-O cycle” S3 will be described in detail. First, a substrate housed in a film forming chamber of an ALD apparatus is heated and held at, for example, 250 ° C. to 400 ° C. Then, the process of “supply of metal precursor gas” S31 is performed. In this step, a metal precursor gas is supplied onto the substrate and adsorbed on the substrate surface. For example, when a hafnium silicate film is formed as the metal silicate film, examples of the hafnium precursor gas include Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ , Hf [N (CH ₃ ) _2. ] ₄ can be used.

  Next, the “purging with an inert gas” step S32 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

Next, the process of “supply of oxygen-containing material” S33 is performed. In this step, an oxidizing gas such as ozone (O ₃ ), water vapor (H ₂ O), or hydrogen peroxide (H ₂ O ₂ ) is supplied to the substrate surface, and oxygen (O ) Form an atomic layer.

  Next, the “purging with an inert gas” step S34 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

  The above is the “metal-O cycle” S3 in which a layer of oxygen (O) atoms is formed on a layer of metal atoms.

  In the case of forming a metal silicate film, a silicon atom layer is formed, and an “Si—O cycle” S2, which is a process of forming an oxygen atom layer on the silicon atom layer, and a metal atom layer are formed. The “metal-O cycle” S3, which is a step of forming an oxygen atom layer on the metal atom layer, is performed at least once. This cycle is defined as one cycle of film formation.

  In the film thickness direction of the metal silicate film, the composition ratio of silicon constituting the metal silicate film is higher on the interface side of the film than on the inner side of the film, compared to the composition ratio of the metal, whereas the film is formed on the interface side of the film. The composition ratio of the metal constituting the metal silicate film on the inner side is made higher than the composition ratio of silicon. For this reason, in the film formation process for forming the interface side of the metal silicate film, one cycle of film formation is a process of forming a layer of oxygen atoms and a layer of oxygen atoms on the silicon atom layer. The “-O cycle” S2 is performed more than the “metal-O cycle” S3, which is a step of forming a layer of metal atoms and forming a layer of oxygen atoms on the layer of metal atoms. On the other hand, in the film formation process for forming the inner side of the metal silicate film, one cycle of film formation is a process for forming a metal atom layer and forming a layer of oxygen atoms on the metal atom layer. The O cycle “S3” is performed more than the “Si—O cycle” S2, which is a step of forming a layer of silicon atoms and forming a layer of oxygen atoms on the silicon atom layer.

  In one cycle of the film formation, the “Si—O cycle” S2 and the “metal-O cycle” S3 may be continuously performed a plurality of times or alternately.

  For example, the “Si-O cycle” S2 can be repeated alternately and repeatedly after the “metal-O cycle” S3 is continuously performed a plurality of times. Conversely, “Si—O cycle” S2 can be repeatedly performed alternately after repeatedly performing “metal-O cycle” S3 a plurality of times.

  Alternatively, the “metal-O cycle” S3 can be continuously performed a plurality of times after the “Si-O cycle” S2 is continuously performed a plurality of times. Conversely, the “Si—O cycle” S2 can be continuously performed a plurality of times after the “metal-O cycle” S3 is continuously performed a plurality of times.

  Then, in each step of film formation, “whether the metal silicate film has a desired composition ratio / film thickness” is determined in step S4 to determine whether the composition ratio and film thickness of the metal silicate film are within a desired range. To do. In this determination, if the composition ratio and the film thickness of the metal silicate film are within the desired ranges, that is, if “Yes”, the process proceeds to “nitriding treatment” S4 in the next step. On the other hand, in the above determination, when the composition ratio and the film thickness of the metal silicate film deviate from the desired ranges, that is, “No”, one cycle of the film formation is performed again. The film formation is repeated until the above determination is “Yes”.

  In the film forming method described above, the determination of “whether the metal silicate film has a desired composition ratio / film thickness” S4 is performed for each cycle of film formation, but “Si—O cycle” S2 and “ After the “metal-O cycle” S3 is repeated a certain number of times, that is, after one cycle of film formation is performed a plurality of times (in the case of the path indicated by the broken line in the drawing), the above “metal silicate film has a desired composition. It is also possible to determine whether or not the ratio / thickness is the film thickness.

Thereafter, the metal silicate film is nitrided by “nitriding” S5. In this nitriding treatment, for example, heat treatment is performed in the range of 600 ° C. to 1000 ° C. in an ammonia (NH ₃ ) gas atmosphere, and nitrogen is introduced into the metal silicate film.

  As described above, one cycle of film formation is one in which the “Si—O cycle” S2 and the “metal-O cycle” S3 are both performed at least once.

  Here, in one cycle of film formation, the composition ratio of silicon [Si / (HF + Si)] and the composition ratio of hafnium when the number of executions of “Si-O cycle” S2 and “metal-O cycle” S3 are changed are used. [Hf / (HF + Si)] is shown in Table 1.

  As shown in Table 1, by performing “Si—O cycle” S2 three times and “metal-O cycle” S3 once, the composition ratio of silicon (Si) becomes 76%, and hafnium (Hf) The composition ratio is 24%. Alternatively, by performing the “Si—O cycle” S2 twice and performing the “metal-O cycle” S3 once, the composition ratio of silicon (Si) becomes 70% and the composition ratio of hafnium (Hf) is 30%. %become. Such a film formation cycle is employed in steps 1 and 3 for forming the interface side of the hafnium silicate film. It should be noted that the number of “Si—O cycles” S2 may be set to 4 or more to further increase the silicon composition ratio.

  And as it enters the inner side, the composition ratio of hafnium is increased. For example, the composition ratio of silicon (Si) is 34% and the composition ratio of hafnium (Hf) is 66% by performing “Si—O cycle” S2 once and “metal-O cycle” S3 three times. become. One cycle of this film formation is preferably employed in step 2 in which the inner side of the hafnium silicate film is formed. It is possible to increase the number of “metal-O cycle” S3 to 4 or more and further increase the composition ratio of hafnium.

  Further, in one cycle of the film formation, by performing the “Si-O cycle” S2 and not performing the “metal-O cycle” S3, the composition ratio of silicon (Si) becomes 100%, and a silicon oxide layer is obtained. You can also. Accordingly, only the interface of the hafnium silicate film can be a silicon oxide layer. On the other hand, by performing only the “metal-O cycle” S3 without performing the “Si—O cycle” S2, the composition ratio of hafnium (Hf) becomes 100%, and a hafnium oxide film can be obtained. Therefore, it is also possible to make a hafnium oxide layer only in the central portion in the film thickness direction of the hafnium silicate film.

In Table 1, in the “Si—O cycle” S2, [SiH (CH ₃ ) ₂ ] ₂₀ is used as the precursor gas for silicon (Si), ozone (O ₃ ) is used as the oxygen-containing material, and purge gas is used. Argon was used. In the “metal-O cycle” S3, Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ is used as the precursor gas of hafnium (Hf), ozone (O ₃ ) is used as the oxygen-containing material, Argon was used as the purge gas. Note that the composition ratios shown in Table 1 above are examples, and the composition of the film formation may vary depending on the source gas.

  Now, the case where “Si-O cycle” S2 is performed more than “metal-O cycle” S3 in one cycle of film formation is referred to as step 1 and step 3, and “Si-O cycle” S2 is “metal-O cycle”. Assuming that the number of steps is less than S3 is Step 2, in the metal silicate film manufacturing method of the present invention, the film is formed in the order of Step 1, Step 2, and Step 3 so that the inside of the film in the film thickness direction of the metal silicate film. The composition ratio of silicon constituting the metal silicate film is higher than the metal composition ratio on the interface side of the film from the side, and the metal silicate is present on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. The metal silicate film of the present invention in which the composition ratio of the metal constituting the film is higher than the composition ratio of silicon can be produced. Therefore, a hafnium silicate film having a desired composition ratio of hafnium and silicon can be formed in the film thickness direction.

  Next, a film forming example to which the above three steps are applied will be described.

  As shown in FIG. 5, first, step 1 is performed. In this step 1, the cycle ratio of “metal-O cycle” S3 is set to less than 1 with respect to the cycle ratio 1 of “Si—O cycle” S2. repeat. By repeating the process at this cycle ratio, a silicon (Si) -rich hafnium silicate film can be formed. That is, on the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. The composition ratio is controlled so as to be less than 100%. Since the interface side of the hafnium silicate film thus controlled has a composition close to that of silicon oxide, the heat resistance is increased and crystallization is less likely to occur by heat treatment. As a result, a crystal grain boundary that becomes a leakage path is less likely to occur, so that when the hafnium silicate film is used as a capacitor insulating film, the problem of the prior art that the leakage current increases through the crystal grain boundary is solved. The By the above step 1, for example, 10% of the film thickness of the hafnium silicate film to be formed is formed.

  Next, step 2 is performed. In this step 2, the cycle ratio of the “metal-O cycle” S3 is made larger than 1 with respect to the cycle ratio 1 of the “Si—O cycle” S2, and the process is repeated. By repeating the process at this cycle ratio, a hafnium (Hf) rich hafnium silicate film can be formed. That is, on the inner side of the hafnium silicate film, the composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and less than or equal to 70%, and the composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%. Thus, the composition ratio is controlled. On the inner side of the hafnium silicate film thus controlled, the composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%, and the composition ratio of silicon to hafnium in the hafnium silicate film is from 0%. Since it is largely 70% or less, the inner side has a composition close to that of hafnium oxide, so that it is possible to suppress a decrease in relative dielectric constant as a metal silicate film. By the above step 2, for example, 80% of the thickness of the hafnium silicate film to be formed is formed.

  Finally, step 3 is performed. In step 3, as in step 1 above, the cycle ratio of “metal-O cycle” S3 is set to less than 1 with respect to the cycle ratio 1 of “Si—O cycle” S2, and the process is repeated. By repeating the process at this cycle ratio, a silicon (Si) -rich hafnium silicate film can be formed. That is, on the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. The composition ratio is controlled so as to be less than 100%. Since the interface side of the hafnium silicate film thus controlled has a composition close to that of silicon oxide, the heat resistance is increased and crystallization is less likely to occur by heat treatment. As a result, a crystal grain boundary that becomes a leakage path is less likely to occur, so that when the hafnium silicate film is used as a capacitor insulating film, the problem of the prior art that the leakage current increases through the crystal grain boundary is solved. The By the above step 3, for example, 10% of the film thickness of the hafnium silicate film to be formed is formed.

  As described above, when the hafnium silicate film is viewed in terms of the total film thickness, it is desirable to repeat the film forming process at a ratio of step 1: step 2: step 3 = 1: 8: 1. For example, when a hafnium silicate film having a total film thickness of 5 nm is formed, the process may be repeated to reach a film thickness of 0.5 nm in step 1 and step 3 and 4 nm in step 2.

Further, as described above, after the hafnium silicate film is formed, heat treatment is performed in the range of 600 ° C. to 1000 ° C. using, for example, an ammonia (NH ₃ ) atmosphere, and nitrogen is introduced into the hafnium silicate film. good.

  In the method for manufacturing the metal silicate film, the determination of “whether the metal silicate film has a desired composition ratio / film thickness” or not is performed for each cycle of film formation. In an actual production line, it may take too much time to determine the film thickness and the composition ratio for each cycle of film formation. Therefore, in one cycle of film formation, the number of executions of “Si-O cycle” S2 and “metal-O cycle” S3 may be derived in advance by experiment or simulation, and film formation may be performed. Then, at the end of the film formation, the determination of “whether the metal silicate film has a desired composition ratio / film thickness” or not is performed. By taking such a sequence, the throughput of film formation can be improved.

The method for producing a metal silicate film of the present invention includes forming a layer of silicon atoms and forming a layer of oxygen atoms on the silicon atom layer, the “Si—O cycle” S2 and a layer of metal atoms, and a metal atom. For example, the interface side of the metal silicate film is formed in order to form the film as one cycle of film formation of at least one of the “metal-O cycle” S3 for forming a layer of oxygen atoms on the metal layer. In the film forming process, one cycle of film forming is to form a metal silicate film close to silicon oxide (SiO ₂ ) by performing “Si-O cycle” S2 more than “metal-O cycle” S3. Can do. As a result, the reaction between the Si interface and the metal is suppressed, and crystallization as a leak path can be prevented. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, capacitor leakage can be reduced. Further, since the metal silicate film is close to SiO ₂ , the heat resistance is improved. On the other hand, in the film formation process for forming the inner side of the metal silicate film, one cycle of film formation is performed by performing “metal-O cycle” S3 more than “Si-O cycle” S2, thereby making the metal close to the metal oxide film. A silicate film can be formed. This makes it possible to increase the relative dielectric constant. For this reason, when this metal silicate film is used as a capacitor insulating film of a capacitor, there is an advantage that the capacitance Cs can be increased. Further, by determining whether the composition ratio and the film thickness of the metal silicate film are within a desired range for each cycle of film formation, the desired film thickness, the desired metal composition ratio, and the silicon composition ratio are adjusted. It becomes possible to control the metal silicate film composition at each step.

  Next, an embodiment of the method for manufacturing a semiconductor device of the present invention will be described with reference to the manufacturing process sectional views of FIGS. 6 and 7, a manufacturing method in which the present invention is applied to a general trench capacitor manufacturing method will be described.

  As shown in FIG. 6A, the chemical treatment of the surface of the semiconductor substrate 11 is performed. For this chemical treatment, for example, dilute hydrofluoric acid is used, and a natural oxide film (not shown) on the surface of the semiconductor substrate 11 is removed. After the chemical treatment, an oxide film 12 is formed on the surface of the semiconductor substrate 11. The oxide film 12 is formed by, for example, using a thermal oxidation method and thermally oxidizing the surface of the semiconductor substrate 11 at, for example, 850 ° C. to deposit an oxide film 12 having a thickness of, for example, about 2 nm. Subsequently, a nitride film 13 is formed on the oxide film 12 without leaving as much as possible. The nitride film 13 is formed to a thickness of about 220 nm at a film formation temperature of 780 ° C., for example. Subsequently, impurities on the surface of the nitride film 13 are removed by chemical treatment. As this chemical solution, for example, a mixed chemical solution of hydrochloric acid and ozone is used. Next, a mask layer 14 is formed on the nitride film 13. The mask layer 14 is formed of, for example, boron silicate glass (BSG), and is formed to a thickness of 1400 nm at a film formation temperature of 700 ° C., for example. Subsequently, a resist film 15 is formed on the oxide film 14 using, for example, a spin coating method. The resist film 15 is formed with a thickness of 800 nm, for example.

  Next, as shown in FIG. 6B, the resist film 15 is processed by a normal lithography technique to form an opening 16 for forming a trench.

  Next, as shown in FIG. 6 (3), the opening 16 is formed in the mask layer 14, the nitride film 13, and the oxide film 12 by using the resist film 15 as an etching mask. For this processing, reactive ion etching can be used. Thereafter, the resist film 15 and particles on the semiconductor substrate 11 are removed. This removal process is based on an ashing process or a chemical process. In this chemical solution treatment, for example, a mixed chemical solution of sulfuric acid and hydrogen peroxide solution can be used.

  Next, as shown in FIG. 6 (4), the semiconductor substrate 11 is etched using the mask layer 14 and the nitride film 13 as an etching mask to form a trench 17. The trench 17 is formed to have a taper, for example. This taper angle is set in the range of, for example, 85 ° to less than 90 °. In the etching process, reactive ion etching is performed. At this time, the trench 17 has a depth of, for example, 5.0 μm to 8.0 μm, and an opening on the surface of the semiconductor substrate 11 has a range of 100 nm to 250 nm. Therefore, a trench having an aspect ratio of 40 or more is formed.

  Next, the mask layer 14 is removed by chemical treatment, for example. For this chemical treatment, for example, a mixed chemical solution of sulfuric acid and hydrofluoric acid can be used. As a result, the surface of the silicon nitride film 13 is exposed as shown in FIG.

  Next, as shown in FIG. 7 (6), the inside of the trench 17 is cleaned as the electrode formation on the plate side. In this cleaning step, for example, cleaning with dilute hydrofluoric acid is used. Thereafter, arsenic (As) or phosphorus (P) is doped into the semiconductor substrate 11 inside the trench 17 by vapor phase diffusion to form the plate electrode 18.

  Next, as shown in FIG. 7 (7), a capacitor insulating film 19 is formed on the inner surface of the trench 17. The capacitor insulating film 19 uses the metal silicate film (for example, hafnium silicate film) described in the first, second, third, etc.

First, in order to remove the natural oxide film in the trench, the substrate is cleaned with dilute hydrofluoric acid in the range of 20 to 60 seconds, and then subjected to heat treatment in the range of 600 ° C. to 1000 ° C. using, for example, an NH ₃ gas atmosphere. Is nitrided. Subsequently, a capacitor insulating film 19 made of a metal silicate film (for example, a hafnium silicate film) is formed by using the ALD method.

  The hafnium silicate film is formed as follows. As shown in FIG. 5, first, step 1 is performed. In this step 1, a silicon atom layer is formed and an oxygen atom layer is formed on the silicon atom layer "Si-O cycle" S2. The cycle ratio of the “metal-O cycle” S3 in which a metal (hafnium) atom layer is formed and an oxygen atom layer is formed on the metal (hafnium) atom layer is set to less than 1 for a cycle ratio of 1. repeat. By repeating the process at this cycle ratio, a silicon (Si) -rich hafnium silicate film can be formed. That is, on the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. The composition ratio is controlled so as to be less than 100%. Since the interface side of the hafnium silicate film thus controlled has a composition close to that of silicon oxide, the heat resistance is increased and crystallization is less likely to occur by heat treatment. As a result, a crystal grain boundary that becomes a leakage path is less likely to occur, so that when the hafnium silicate film is used as a capacitor insulating film, the problem of the prior art that the leakage current increases through the crystal grain boundary is solved. The By the above step 1, for example, 10% of the film thickness of the hafnium silicate film to be formed is formed.

  Next, step 2 is performed. In this step 2, the cycle ratio of the “metal-O cycle” S3 is made larger than 1 with respect to the cycle ratio 1 of the “Si—O cycle” S2, and the process is repeated. By repeating the process at this cycle ratio, a hafnium (Hf) rich hafnium silicate film can be formed. That is, on the inner side of the hafnium silicate film, the composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and less than or equal to 70%, and the composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%. Thus, the composition ratio is controlled. On the inner side of the hafnium silicate film thus controlled, the composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%, and the composition ratio of silicon to hafnium in the hafnium silicate film is from 0%. Since it is largely 70% or less, the inner side has a composition close to that of hafnium oxide, so that it is possible to suppress a decrease in relative dielectric constant as a metal silicate film. By the above step 2, for example, 80% of the thickness of the hafnium silicate film to be formed is formed.

  Finally, step 3 is performed. In this step 3, similarly to step 1, the cycle ratio of the “metal-O cycle” S3 is set to less than 1 with respect to the cycle ratio 1 of the “Si—O cycle” S2. repeat. By repeating the process at this cycle ratio, a silicon (Si) -rich hafnium silicate film can be formed. That is, on the interface side (front and back sides) of the hafnium silicate film, the composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and not more than 30%, and the composition ratio of silicon to hafnium in the hafnium silicate film is 70%. The composition ratio is controlled so as to be less than 100%. Since the interface side of the hafnium silicate film thus controlled has a composition close to that of silicon oxide, the heat resistance is increased and crystallization is less likely to occur by heat treatment. As a result, a crystal grain boundary that becomes a leakage path is less likely to occur, so that when the hafnium silicate film is used as a capacitor insulating film, the problem of the prior art that the leakage current increases through the crystal grain boundary is solved. The By the above step 3, for example, 10% of the film thickness of the hafnium silicate film to be formed is formed.

  As described above, when the hafnium silicate film is viewed in terms of the total film thickness, it is desirable to repeat the film forming process at a ratio of step 1: step 2: step 3 = 1: 8: 1. For example, when a hafnium silicate film having a total film thickness of 5 nm is formed, the process may be repeated to reach a film thickness of 0.5 nm in step 1 and step 3 and 4 nm in step 2.

  The “Si—O cycle” S2 for forming the silicon atom layer and forming an oxygen atom layer on the silicon atom layer is performed as follows.

As described with reference to FIG. 4, first, the substrate that has been subjected to the above pretreatment is housed in the film forming chamber of the ALD apparatus, and the substrate is heated and held at, for example, 250 ° C. to 400 ° C. Then, the process of “supplying Si precursor gas” S21 is performed. In this step, silicon (Si) precursor gas is supplied onto the substrate and adsorbed on the substrate surface. As the Si precursor gas, for example, Si [N (CH ₃ ) (C ₂ H ₅ )] ₄ or [SiH (CH ₃ ) ₂ ] ₂₀ can be used.

  Next, the “purging with an inert gas” step S22 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

Next, the process of “supply of oxygen-containing material” S23 is performed. In this step, ozone (O ₃ ) or water (H ₂ O) is supplied to the substrate surface to form an oxygen (O) atom layer on the silicon (Si) atom layer.

  Next, the “purging with inert gas” step S24 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

  As described above, the “Si—O cycle” S2 for forming a layer of oxygen (O) atoms on a layer of silicon (Si) atoms may be performed.

  In addition, the “metal-O cycle” S3 for forming a layer of metal (hafnium) atoms and forming a layer of oxygen atoms on the layer of metal (hafnium) atoms is performed as follows.

As described with reference to FIG. 4, first, the substrate accommodated in the film forming chamber of the ALD apparatus is heated and held at, for example, 250 ° C. to 400 ° C. Then, the process of “supply of metal precursor gas” S31 is performed. In this step, a metal precursor gas is supplied onto the substrate and adsorbed on the substrate surface. For example, when a hafnium silicate film is formed as the metal silicate film, examples of the hafnium precursor gas include Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ , Hf [N (CH ₃ ) _2. ] ₄ can be used.

  Next, the “purging with an inert gas” step S32 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

Next, the process of “supply of oxygen-containing material” S33 is performed. In this step, an oxidizing gas such as ozone (O ₃ ), water vapor (H ₂ O), or hydrogen peroxide (H ₂ O ₂ ) is supplied to the substrate surface, and oxygen (O ) Form an atomic layer.

  Next, the “purging with an inert gas” step S34 is performed. In this step, argon (Ar) gas is supplied to the substrate surface to purge the film formation atmosphere and suppress the gas phase reaction of the residual gas. As the inert gas, other rare gas such as argon, nitrogen gas, or the like can be used, but argon is preferably used in consideration of purge efficiency, cost, and the like.

  The “metal-O cycle” S3 for forming a layer of oxygen (O) atoms on the metal atom layer as described above may be performed.

After the capacitor insulating film 19 made of the hafnium silicate film is formed, heat treatment is performed in the range of 600 ° C. to 1000 ° C. using, for example, an ammonia (NH ₃ ) atmosphere, and nitrogen is introduced into the hafnium silicate film. good.

  Next, as shown in FIG. 7 (8), the node electrode 20 is formed on the capacitor insulating film 19 to fill the trench 17. As the node electrode 20, for example, an amorphous silicon film doped with arsenic (As) is formed at a film formation temperature of 480 ° C. to 530 ° C. Subsequent processes can be performed by a conventionally known semiconductor manufacturing process.

  In the semiconductor device manufacturing method, since the metal silicate film of the present invention is used for the capacitor insulating film 19, even if a heat process of about 1000 ° C. is performed after the capacitor insulating film 19 is formed, the capacitor insulating film 19 Since the silicon-rich layer is formed at the interface, the heat resistance is improved, the crystallization inside the metal silicate film is prevented, and the generation of crystal grain boundaries serving as a leakage current path is suppressed. Further, since the inside of the capacitor insulating film 19 has a composition close to that of hafnium oxide, the relative dielectric constant can be increased as compared with the conventional hafnium silicate film. For this reason, the capacitor capacitance Cs can be increased. Therefore, a film having a higher dielectric constant than that of the conventional capacitor insulating film is formed, and application to next-generation semiconductor processes (for example, 65 nm generation, 45 nm generation, and later generations) becomes possible by increasing Cs. .

  The metal silicate film of the present invention, its manufacturing method and semiconductor device, and its manufacturing method can be applied to a capacitor insulating film of a capacitor, and the capacitor can be applied to a memory element of a memory device.

It is explanatory drawing which showed one Example which concerns on a metal silicate film | membrane. 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device. It is the circuit diagram which showed one Example which concerns on a semiconductor device. It is the flowchart which showed one Example which concerns on the manufacturing method of a metal silicate film | membrane. It is explanatory drawing which showed one Example which concerns on the manufacturing method of a metal silicate film | membrane. It is manufacturing process sectional drawing which showed one Example concerning the manufacturing method of a semiconductor device. It is manufacturing process sectional drawing which showed one Example concerning the manufacturing method of a semiconductor device.

Explanation of symbols

  101 ... Metal silicate film

Claims (28)

In the film thickness direction of the metal silicate film, the composition ratio of silicon constituting the metal silicate film is higher than the composition ratio of the metal on the interface side of the film from the inner side of the film,
A metal silicate film characterized in that, in the film thickness direction of the metal silicate film, the composition ratio of the metal constituting the metal silicate film is higher than the composition ratio of silicon on the inner side of the film from the interface side of the film. The metal silicate film according to claim 1, wherein the metal silicate film is made of a hafnium silicate film. The metal silicate film is made of a hafnium silicate film,
On the interface side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and less than or equal to 30%.
The metal silicate film according to claim 1, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is 70% or more and less than 100%. The metal silicate film is made of a hafnium silicate film,
On the inside side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%,
2. The metal silicate film according to claim 1, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and equal to or less than 70%. The metal silicate film according to claim 1, wherein the metal silicate film is a film heat-treated in an atmosphere containing nitrogen. In the film thickness direction of the metal silicate film, the composition ratio of silicon constituting the metal silicate film is higher than the composition ratio of the metal on the interface side of the film from the inner side of the film,
In the film thickness direction of the metal silicate film, the metal silicate film has a higher composition ratio than the silicon composition ratio on the inner side of the film from the film interface side.
The metal silicate film is formed by forming a layer of silicon atoms and forming an oxygen atom layer on the silicon atom layer, and forming a metal atom layer and an oxygen atom layer on the metal atom layer. It is assumed that one of the steps of forming at least one or more times is one cycle of film formation,
In the film formation step of forming the interface side of the metal silicate film, one cycle of the film formation includes forming a layer of metal atoms and forming a layer of silicon atoms from a step of forming a layer of oxygen atoms on the layer of metal atoms. Many steps of forming an oxygen atom layer on a silicon atom layer,
In the film forming step of forming the inner side of the metal silicate film, one cycle of the film formation includes a layer of silicon atoms than a step of forming a layer of metal atoms and an oxygen atom layer on the metal atom layer. Many steps of forming an oxygen atom layer on a silicon atom layer,
Performing a step of determining whether or not the composition ratio and the film thickness of the metal silicate film are within a desired range after each cycle of the film formation or after repeating the film formation cycle a predetermined number of times,
In the determination, if the composition ratio and the film thickness of the metal silicate film are within a desired range, the film formation is terminated,
In the determination, when the composition ratio and the film thickness of the metal silicate film deviate from a desired range, one cycle of the film formation is performed again. The method of manufacturing a metal silicate film, The method for producing a metal silicate film according to claim 6, wherein after the metal silicate film is formed, the metal silicate film is heat-treated in an atmosphere containing nitrogen. The method for producing a metal silicate film according to claim 6, wherein the step of forming the layer of silicon atoms and the step of forming a layer of oxygen atoms on the layer of silicon atoms are performed by an atomic layer deposition method. The method for producing a metal silicate film according to claim 6, wherein the step of forming the metal atom layer and the step of forming the oxygen atom layer on the metal atom layer are performed by an atomic layer deposition method. The step of forming the layer of silicon atoms and forming the layer of oxygen atoms on the layer of silicon atoms,
Supplying a silicon precursor gas into the film-forming atmosphere;
Supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere;
Supplying an oxygen-containing material in the film-forming atmosphere;
The method for producing a metal silicate film according to claim 6, further comprising: supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere. Forming the metal atom layer and forming the oxygen atom layer on the metal atom layer,
Supplying a metal precursor gas in a film-forming atmosphere;
Supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere;
Supplying an oxygen-containing material in the film-forming atmosphere;
The method for producing a metal silicate film according to claim 6, further comprising: supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere. The metal silicate film is made of a hafnium silicate film,
In the film forming process for forming the interface side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and 30% or less,
The method for producing a metal silicate film according to claim 6, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is 70% or more and less than 100%. The metal silicate film is made of a hafnium silicate film,
In the film forming process for forming the inner side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%,
The method for producing a metal silicate film according to claim 6, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and equal to or less than 70%. Before performing one cycle of the first film formation,
The method for producing a metal silicate film according to claim 6, wherein after the film formation surface is cleaned, nitriding treatment is performed on the film formation surface. A semiconductor device comprising a capacitor with a metal silicate film sandwiched between electrodes,
The metal silicate film is
The composition ratio of silicon constituting the metal silicate film is higher than the composition ratio of the metal on the interface side of the film from the center of the film in the film thickness direction of the metal silicate film,
A semiconductor device characterized in that a composition ratio of a metal constituting the metal silicate film is higher than a composition ratio of silicon on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. The semiconductor device according to claim 15, wherein the metal silicate film is made of a hafnium silicate film. The metal silicate film is made of a hafnium silicate film,
On the interface side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and less than or equal to 30%.
The semiconductor device according to claim 15, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is 70% or more and less than 100%. The metal silicate film is made of a hafnium silicate film,
On the inside side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%,
The semiconductor device according to claim 15, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and equal to or less than 70%. The semiconductor device according to claim 15, wherein the metal silicate film is a film that is heat-treated in an atmosphere containing nitrogen. A method of manufacturing a semiconductor device comprising a capacitor with a metal silicate film sandwiched between electrodes,
The metal silicate film forming step includes:
At least one of the step of forming a layer of silicon atoms and forming a layer of oxygen atoms on the layer of silicon atoms and a step of forming a layer of metal atoms and a layer of oxygen atoms on the layer of metal atoms are included. Doing more than once is one cycle of film formation,
In the film formation step of forming the interface side of the metal silicate film, one cycle of the film formation includes forming a layer of metal atoms and forming a layer of silicon atoms from a step of forming a layer of oxygen atoms on the layer of metal atoms. Many steps of forming an oxygen atom layer on a silicon atom layer,
In the film forming step of forming the inner side of the metal silicate film, one cycle of the film formation includes a layer of silicon atoms than a step of forming a layer of metal atoms and an oxygen atom layer on the metal atom layer. Many steps of forming an oxygen atom layer on a silicon atom layer,
Performing a step of determining whether or not the composition ratio and the film thickness of the metal silicate film are within a desired range after each cycle of the film formation or after repeating the film formation cycle a predetermined number of times,
In the determination, if the composition ratio and the film thickness of the metal silicate film are within a desired range, the film formation is terminated,
In the determination, when the composition ratio and the film thickness of the metal silicate film deviate from the desired range, by performing one cycle of the film formation again,
In the film thickness direction of the metal silicate film, the composition ratio of silicon constituting the metal silicate film is higher than the composition ratio of the metal on the interface side of the film from the inner side of the film,
A metal silicate film having a metal composition ratio higher than that of silicon is formed on the inner side of the film from the interface side of the film in the film thickness direction of the metal silicate film. A method for manufacturing a semiconductor device. 21. The method of manufacturing a semiconductor device according to claim 20, wherein after the metal silicate film is formed, the metal silicate film is subjected to heat treatment in an atmosphere containing nitrogen. 21. The method of manufacturing a semiconductor device according to claim 20, wherein the step of forming the silicon atom layer and the step of forming the oxygen atom layer on the silicon atom layer are performed by an atomic layer deposition method. 21. The method of manufacturing a semiconductor device according to claim 20, wherein the step of forming the metal atom layer and the step of forming the oxygen atom layer on the metal atom layer are performed by an atomic layer deposition method. The step of forming the layer of silicon atoms and forming the layer of oxygen atoms on the layer of silicon atoms,
Supplying a silicon precursor gas into the film-forming atmosphere;
Supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere;
Supplying an oxygen-containing material in the film-forming atmosphere;
The method for manufacturing a semiconductor device according to claim 20, further comprising: supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere. Forming the metal atom layer and forming the oxygen atom layer on the metal atom layer,
Supplying a metal precursor gas in a film-forming atmosphere;
Supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere;
Supplying an oxygen-containing material in the film-forming atmosphere;
The method for manufacturing a semiconductor device according to claim 20, further comprising: supplying an inert gas into the film formation atmosphere to purge the film formation atmosphere. The metal silicate film is made of a hafnium silicate film,
In the film forming process for forming the interface side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is greater than 0% and 30% or less,
21. The method of manufacturing a semiconductor device according to claim 20, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is 70% or more and less than 100%. The metal silicate film is made of a hafnium silicate film,
In the film forming process for forming the inner side of the hafnium silicate film,
The composition ratio of hafnium to silicon in the hafnium silicate film is 30% or more and less than 100%,
21. The method of manufacturing a semiconductor device according to claim 20, wherein a composition ratio of silicon to hafnium in the hafnium silicate film is greater than 0% and equal to or less than 70%. Before performing one cycle of the first film formation,
21. The method of manufacturing a semiconductor device according to claim 20, wherein after the film formation surface is cleaned, nitriding treatment is performed on the film formation surface.

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