KR100343144B1 - Thin film formation method using atomic layer deposition - Google Patents

Abstract

The thin film formation method using the atomic layer deposition method of the present invention forms a thin film on the substrate in the cycle of the first reactant injection, purge, the second reactant injection and purge containing the element and ligand constituting the thin film in the reaction chamber containing the substrate . At this time, the bond energy of the second reactant with the element forming the thin film is formed by the chemical reaction of the element forming the thin film and the second reactant using a material larger than the ligand, and at the same time prevents the formation of side reactions. do. Alternatively, the second reactant may be formed using a material without a hydroxyl group, and the third reactant having a hydroxyl group may be reacted again after purging the second reactant to suppress the generation of byproducts of the hydroxyl group in the thin film. Alternatively, after the second reactant purge, a third reactant for removing impurities and improving stoichiometry is injected and purged. By doing in this way, this invention can obtain the thin film which is excellent in stoichiometry without containing an impurity in a thin film.

Description

Thin film formation method using atomic layer deposition

The present invention relates to a thin film formation method, and more particularly, to a thin film formation method using atomic layer deposition (ALD).

In general, a thin film is a dielectric layer of a semiconductor device, a transparent conductor of a liquid-crystal display, and a protective layer of an electroluminescent thin film display. protective layer) and the like. The thin film is formed by sol-gel, sputtering, electro-plating, evaporation, chemical vapor deposition, ALD, or the like.

Among them, the ALD method has an advantage that it is possible to obtain an excellent step coverage and a low temperature process compared to the chemical vapor deposition method. The ALD method is a method of forming a thin film by decomposing reactants by chemical exchange through periodic supply of each reactant rather than pyrolysis. Here, the formation method of the aluminum oxide film which can be used as a dielectric film of a semiconductor element using the conventional atomic layer deposition method is demonstrated in detail.

FIG. 1 is a flowchart illustrating a process of forming an aluminum oxide film using a conventional atomic layer deposition method, and FIGS. 2A to 2D are views illustrating a reaction mechanism when forming an aluminum oxide film of FIG. 1.

Specifically, trimethyl aluminum (Al (CH ₃ )) composed of a first reactant (A), that is, a thin film of aluminum (a ₁ ) and a methyl ligand (a ₂ ) in a reaction chamber (not shown) loaded with the substrate S. ₃ , "TMA") is injected (step 1). Subsequently, the first reactant A that is in physical bonding is removed by purging (purging) the inert gas (step 3). In this case, as illustrated in FIG. 2A, the first reactant A is chemisorbed onto the substrate S. As shown in FIG.

Subsequently, the second reactant (B), that is, the first reactant (A) is injected with a second reactant (B), that is, water vapor (H ₂ O) composed of oxygen (b ₁ ) and hydrogen radicals (b ₂ ) forming a thin film ( Step 5). In this case, as shown in FIG. 2B, the second reactant (B) is chemically adsorbed to the first reactant (A).

Here, the hydrogen radical (b ₂ ) of the chemisorbed second reactant (B) is transferred to the methyl ligand (a ₂ ) of the first reactant (A) as shown in FIG. The methyl ligand is isolated. Then, the hydrogen radical (b ₂ ) of the transferred second reactant (B) reacts with the methyl ligand (a ₂ ) of the separated first reactant (A) to CH ₄ , as shown in Formula 1 and FIG. 2D. To form a volatile gaseous substance (D). The aluminum oxide film C is formed on the substrate S by the reaction of aluminum a ₁ of the first reactant A and oxygen b ₁ of the second reactant B.

2Al (CH ₃ ) ₃ + 3H ₂ O → Al ₂ O ₃ + 6CH ₄

Next, the volatile gaseous substance (D) made up of CH ₄ and unreacted water vapor are removed by purging (purging) the inert gas (step 7). Subsequently, it is confirmed whether or not the thickness of the formed aluminum oxide film is an appropriate thickness (step 9), and the steps 1 to 7 are repeatedly cycled as necessary.

However, conventional ALD method is OH radicals to the residual according to the movement of the hydrogen radicals (b _2), as described in the formula (2) to be described later, so-methyl-ligand (a ₂₎ is removed by the movement of the hydrogen radicals (b ₂₎ Side reactions occur,

Al (CH ₃ ) ₃ + 3H ₂ O → Al (OH) ₃ + 3CH ₄

When this side reaction occurs, unwanted impurities such as Al (OH) ₃ are contained in the aluminum oxide film (C). When impurities such as Al (OH) ₃ are included in this way, desired thin film properties cannot be obtained. In particular, when the aluminum oxide film including Al (OH) ₃ is applied to the dielectric film of the semiconductor device, the aluminum oxide film acts as a trap site or a current leakage site of electrons, thereby degrading the property of the dielectric film. .

Therefore, the technical problem to be achieved by the present invention is to provide a thin film formation method that can obtain an excellent stoichiometric thin film by suppressing the formation of unwanted impurities when using the atomic layer deposition method.

1 is a flowchart illustrating a process of forming an aluminum oxide film using a conventional atomic layer deposition method,

2A to 2D are views for explaining a reaction mechanism in forming the aluminium oxide film of FIG.

3 is a schematic diagram illustrating an atomic layer thin film forming apparatus used in the method for forming a thin film using the atomic layer deposition method of the present invention.

4A to 4D are diagrams for explaining the reaction mechanism of the thin film forming method using the atomic layer deposition method according to the first embodiment of the present invention,

5 is a flowchart illustrating a process of forming an aluminum oxide film according to a first embodiment of the present invention.

6A to 6D are diagrams for explaining a reaction mechanism when forming an aluminum oxide film using the atomic layer deposition method of FIG. 5,

7 and 8 are graphs showing RGA data when forming an aluminum oxide film according to the prior art and the first embodiment of the present invention, respectively.

9 is a graph showing the thickness of the aluminum oxide film according to the number of cycles when forming the aluminum oxide film according to the prior art and the first embodiment of the present invention,

10 is a graph showing the stress history according to the temperature of the aluminum oxide film formed by the conventional embodiment and the first embodiment of the present invention,

FIG. 11 is a graph showing thickness shrinkage ratios according to post annealing conditions of aluminum oxide films formed according to the first embodiment of the present invention.

12 and 13 are graphs showing absorption constants and refractive indices according to wavelengths of aluminum oxide films formed by conventional and first embodiments of the present invention, respectively.

FIG. 14 is a graph showing wet etch rates according to post annealing temperatures and atmospheric gases of aluminum oxide films formed by conventional and first exemplary embodiments, respectively.

15 is a cross-sectional view showing a capacitor structure of a semiconductor device employing a dielectric film formed according to the first embodiment of the present invention,

16 is a cross-sectional view showing a transistor structure of a semiconductor device employing a dielectric film formed according to the first embodiment of the present invention,

FIG. 17 is a graph illustrating a leakage current characteristic according to an applied voltage of a conventional capacitor and a SIS capacitor employing a dielectric film formed according to a first embodiment of the present invention.

FIG. 18 is a graph illustrating a takeoff voltage according to an equivalent oxide film of a SIS capacitor employing a dielectric film formed according to a first embodiment of the present invention.

19 is a graph illustrating leakage current characteristics according to an applied voltage of a MIS capacitor employing a dielectric film formed according to a first embodiment of the present invention.

20 is a graph comparing leakage current characteristics of a MIS capacitor employing a dielectric film formed by a first embodiment of the present invention and a conventional capacitor,

21A and 21B are graphs illustrating leakage current characteristics according to an applied voltage when the aluminum oxide film according to the first embodiment of the present invention and the first embodiment of the present invention are used as a capping film of a MIM capacitor, respectively.

22 is a flowchart illustrating a second embodiment of a thin film forming method using the atomic layer deposition method of the present invention.

23A to 23D are diagrams for explaining a coupling relationship of reactants adsorbed on a substrate when forming an aluminum oxide film according to the thin film formation method using the atomic layer deposition method of the second embodiment of the present invention.

24 is an x-ray photoelectron spectroscopy (XPS) graph of an aluminum oxide film formed by a conventional atomic layer deposition method,

25A and 25B are graphs showing leakage current characteristics of aluminum oxide films manufactured by the conventional method and the second embodiment of the present invention, respectively.

26 is a flowchart illustrating a thin film formation method using the atomic layer deposition method according to the third embodiment of the present invention,

FIG. 27 is a timing diagram showing a supply of a reactant in forming a thin film using the atomic layer deposition method according to the third embodiment of the present invention.

28 is a graph showing the thickness per cycle of an aluminum oxide film manufactured by the method for forming an atomic layer thin film of the third embodiment of the present invention,

29 is a graph illustrating the uniformity in the substrate of the aluminum oxide film manufactured by the method for forming an atomic layer thin film according to the third embodiment of the present invention,

30A and 30B illustrate an aluminum peak of an aluminum oxide film prepared by the method of forming an atomic layer thin film according to the prior art and the third embodiment of the present invention using x-ray photoelectron spectroscopy (XPS), respectively. It's a graph,

31A and 31B are graphs of carbon peaks of aluminum oxide films prepared by a thin film forming method using the atomic layer deposition method according to the prior art and the third embodiment of the present invention, respectively, using XP;

32 is a flowchart illustrating a method of forming an atomic layer thin film according to a fourth embodiment of the present invention.

In order to achieve the above technical problem, a thin film formation method using an atomic layer deposition method according to an embodiment of the present invention is injected into the reaction chamber including a substrate by injecting a first reactant containing an element and a ligand forming a thin film on the substrate The first reactant is chemisorbed. The reaction chamber is then purged with an inert gas to remove the physisorbed first reactant. Subsequently, injecting a second reactant having a binding energy greater than that of the ligand into the reaction chamber to form a thin film in atomic layer units by chemical reaction of the element forming the thin film and the second reactant; At the same time the ligand is removed without the formation of side reactants.

In particular, the present invention separates the ligand of the first reactant (A) by the binding energy difference without the transfer of radicals from the second reactant (B) to the first reactant (A). Then, a volatile gaseous substance is formed by the binding between the ligands, and the gaseous substance is removed by purging. Accordingly, the present invention can reduce the impurities generated in the thin film due to side reactions due to the absence of radical movement, thereby obtaining an excellent stoichiometric thin film.

In addition, in the thin film formation method using the atomic layer deposition method according to another embodiment of the present invention, after the first reactant is chemisorbed on the substrate, the reaction chamber is purged with an inert gas to remove the physisorbed first reactant. A second reactant containing no hydroxyl group is injected into the reaction chamber to replace the chemisorbed first reactant with a metal-oxygen atomic layer. The reaction chamber is purged with an inert gas to remove the physisorbed second reactant. A third reactant is injected into the reaction chamber to replace the remainder of the chemisorbed first reactant with a metal-oxygen atomic layer to form a metal oxide film in atomic layer units in a state where generation of hydroxyl groups is suppressed. Furthermore, after injection of the third reactant, a fourth reactant, such as ozone gas, may be injected and purged with an inert gas for impurity removal and stoichiometric enhancement.

Preferably, the first reactant uses a metal reactant, the second reactant without a hydroxyl group uses N ₂ O, O ₂ , O _3, or CO ₂ , and the third reactant uses an oxidizing gas. It is preferable to maintain the temperature of the reaction chamber from 100 to 400 ℃ from the injection step of the first reactant to the injection step of the third reactant. When the substrate is a silicon substrate, an oxidizing gas may be injected before the first reactant is injected to terminate the dangling bond on the surface of the substrate.

In addition, in the method of forming an atomic layer thin film according to another embodiment of the present invention, the first reactant is chemically adsorbed on a substrate and the reaction chamber is purged with an inert gas to remove the first adsorbed physisorbed substance. The second reactant is injected into the reaction chamber to form a thin film of atomic layer units by chemical substitution of the first reactant and the second reactant. The reaction chamber is purged with an inert gas to remove the second adsorbed physisorbed material, and then a third reactant for removing impurities and improving stoichiometry is injected into the reaction chamber in which the thin film is formed.

Preferably, the first reactant uses a metal reactant, and the second and third reactants use an oxidizing gas. In addition, it is preferable that the first reactant uses a metal reactant, and the second and third reactants use a nitriding gas. When the substrate is a silicon substrate, an oxidizing gas or nitriding gas may be further injected before the first reactant is injected to terminate the dangling bond on the surface of the substrate. It is preferable to maintain the temperature of the reaction chamber from 100 to 400 ℃ from the injection step of the first reactant to the injection step of the third reactant.

The method for forming an atomic layer thin film of the present invention as described above can prevent or suppress the generation of unwanted by-products such as hydroxyl groups to obtain a thin film having no stoichiometry and having excellent stoichiometry.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; However, embodiments of the present invention illustrated below may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. In the drawings, the size or thickness of films or regions is exaggerated for clarity. In addition, when a film is described as "on" another film or substrate, the film may be directly on top of the other film, and a third other film may be interposed therebetween.

3 is a schematic diagram illustrating an atomic layer thin film forming apparatus used in the method for forming a thin film using the atomic layer deposition method of the present invention.

Specifically, the atomic layer thin film forming apparatus used in the atomic layer thin film forming method of the present invention includes a reaction chamber 11 that can be heated by an external heater (not shown), and a substrate 15, for example, a silicon substrate. A susceptor 13 installed at the bottom of the reaction chamber 11 and a shower head 17 installed at the top of the susceptor 13 so that reaction gases are injected into the reaction chamber 11. And a vacuum pump 19 connected to the reaction chamber 11 to control the pressure in the reaction chamber 11.

The shower head 17 is connected to two gas inlets A and B separated from each other. Then, the first reactant, the inert gas, the second reactant, and the third reactant are injected into the shower head 17. The first reactant is a metal reactant, the inert gas is a nitrogen gas or an argon gas, the second reactant is an oxidizing gas that does not contain a hydroxyl group, such as N ₂ O, O ₂ , O ₃ or CO ₂ gas or water vapor, The third reactant is water vapor or a substance containing oxygen radicals as an activated oxidant, such as ozone, plasma O ₂ , plasma N ₂ O. In FIG. 3, the second reactant and the third reactant are separately configured for convenience, but may also be configured as one.

In addition, a first reactant and an inert gas are injected into the reaction chamber 11 through the gas injection pipe A, and a second reactant and a third reactant react through the gas injection pipe B. It is injected into the chamber 11. The gas pipes of the first reactant, the second reactant, and the third reactant are different from each other in order to suppress the reaction in one gas pipe A or B. Injection of the first reactant and the inert gas into the reaction chamber 11 is controlled by a first valve V1 and a second valve V2, respectively, and the second reactant and the third reactant are respectively a third reactant. Injection into the reaction chamber 11 is controlled by the valve V3 and the fourth valve V4.

Hereinafter, various embodiments of the thin film forming method using the atomic layer thin film forming apparatus of FIG. 3 will be described.

First embodiment

4A to 4D are diagrams for explaining the reaction mechanism of the thin film formation method using the atomic layer deposition method according to the first embodiment of the present invention.

Specifically, a first reactant A including a thin film element (a ₁ ) and a ligand (a ₂ ) is injected into a substrate (15 of FIG. 3), for example, a reaction chamber 11 loaded with a silicon substrate. 15) After chemisorbing the first reactant (A) onto the first reactant (A), the physically bound first reactant (A) is removed by purging with an inert gas (FIG. 4A).

Subsequently, the second reactant B is injected into the reaction chamber 11 to which the first reactant A is adsorbed. In this case, the second reactant (B) is chemically adsorbed to the first reactant (A). Here, the second reactant (B) uses an incomplete material having a high reactivity with the first reactant (A). The second reactant (B) is an element (a) in which the binding energy between the second reactant (B) and the element (a ₁ ) forming a thin film of the first reactant (A) forms a thin film of the first reactant (A). ₁ ) and a material larger than the binding energy of the ligand (a ₂ ) is used (Fig. 4b).

Subsequently, the binding energy between the second reactant (B) and the element (a ₁ ) forming the thin film of the first reactant (A) is the element (a ₁ ) and the ligand (a) forming the thin film of the first reactant (A). ₂ ) the second reactant (B) tries to bond with the element (a ₁ ) forming a thin film of the first reactant (A) and the ligand (a ₂ ) is separated from the first reactant (A) because it is larger than the binding energy with 4c).

Next, since the ligand (a ₂ ) separated from the first reactant (A) is in an unstable state, a volatile gaseous substance (D) is formed by the binding between the ligands (a ₂ ). On the substrate 15, the thin film C in atomic layer units is formed by the reaction between the element a ₁ constituting the thin film of the first reactant A and the second reactant B. The volatile gaseous substance (D) is removed by purging the inert gas (Fig. 4d).

Next, a case where the thin film forming method using the bonding energy difference described with reference to FIGS. 4A to 4D is applied to the forming process of the aluminum oxide film will be described as an example.

5 is a flowchart illustrating a process of forming an aluminum oxide film according to a first embodiment of the present invention, and FIGS. 6A to 6D are reaction mechanisms when forming an aluminum oxide film using the atomic layer deposition method of FIG. 5. Figures to illustrate.

Specifically, trimethyl aluminum (Al (CH) composed of aluminum (a ₁ ) and methyl ligand (a ₂ ) forming a thin film as a first reactant in a reaction chamber 11 loaded with a substrate (15 of FIG. 3), for example, a silicon substrate. ₃ ) ₃ , TMA: "A") is injected (step 101). Subsequently, the TMA that is physically bonded is removed by purging the inert gas (step 103). In this case, TMA is chemisorbed onto the substrate 15 as shown in FIG. 6A.

Next, ozone B, which is an activated oxidant activated as a second reactant, is injected into the reaction chamber 11 to which TMA is adsorbed (step 105). In this case, ozone (B) is chemically adsorbed to aluminum (a ₁ ) of the TMA as shown in Figure 6b.

In this case, the ozone (B) is an incomplete substance having high reactivity with TMA. In addition, the ozone (B) is in the TMA aluminum (a ₁₎ the binding energy the aluminum of the TMA of about 540kJ / mol with (a ₁₎ and methyl ligand (a ₂₎ the binding energy (e.g., Al-C bond between the energy ) Is greater than 255 kJ / mol. Since the binding energy of the ozone (B) and aluminum (a ₁ ), an element forming a thin film of TMA, is higher than the binding energy of aluminum (a ₁ ) and methyl ligand (a ₂ ), an element forming a thin film of TMA. As shown in 6c, the methyl ligand (a ₂ ) is separated from the TMA.

In addition, since the methyl ligand (a ₂ ) separated from the TMA is in an unstable state, as shown in FIG. 6D, the methyl ligand (a ₂ ) forms a volatile gaseous substance (D) consisting of C ₂ H ₆ by binding between the methyl ligands (a ₂ ). . The aluminum oxide film C in atomic layer units is formed on the substrate 15 by the reaction of aluminum (a ₁ ) and ozone (B) forming a thin film of TMA.

2Al (CH ₃ ) ₃ + O ₃ → Al ₂ O ₃ + 3C ₂ H ₆

Next, the reaction chamber is secondarily purged with an inert gas to remove the C ₂ H ₆ volatile gaseous substance (D) and unreacted methyl ligand (a ₂ ) (step 107). Subsequently, it is confirmed whether or not the thickness of the formed aluminum oxide film is an appropriate thickness (step 109), and the steps of step 107 are periodically repeated as necessary in step 101.

In this embodiment, although ozone is used as the second reactant, ozone may be further activated by using ultraviolet rays. In addition, instead of ozone, plasma oxygen (O ₂ ) or plasma nitrogen oxide (N ₂ O) may be used as the activated oxidizing agent.

TMA + O ₂ (activated) ⇒ 4Al (CH ₃ ) ₃ + 3O ₂ → Al ₂ O ₃ + 6C ₂ H ₆

7 and 8 are graphs showing RGA data when forming an aluminum oxide film according to the prior art and the first embodiment of the present invention, respectively. 7 and 8, the sections indicated by the arrows are sections in which the aluminum oxide film is formed.

Specifically, as described above, since the ligand is removed depending on the reaction mechanism of the second reactant (B) and the first reactant (A), the material generated during the process also varies. That is, in the case of using TMA as the first reactant (A) and steam (H ₂ O) as the second reactant (B) as shown in FIG. 7, CH ₃ ⁺ and CH ₄ ⁺ generated by receiving hydrogen radicals from water vapor Is detected as a major byproduct. In contrast, when ozone is used as the first reactant (A) as the TMA and the second reactant (B) as shown in FIG. 8 of the present invention, the CH ₃ ligand is removed and C ₂ H ₅ ⁺ or C ₂ H ₆ ⁺ It can be seen that it is detected as a major by-product.

9 is a graph showing the thickness of the aluminum oxide film according to the number of cycles when forming the aluminum oxide film according to the prior art and the first embodiment of the present invention.

Specifically, since the atomic layer deposition method is a surface control process, the thickness of the deposited thin film is determined by the number of cycles forming the supply cycle of each reactant. That is, when the thickness increases linearly with the cycle, it means that a thin film is formed by atomic layer deposition. As shown in Figure 9, both conventional and the present invention can be seen that the thin film is formed by the atomic layer deposition method as the thickness increases linearly.

By the way, there is a difference in the latency cycle between the prior art using water vapor as the second reactant (B) and the present invention using ozone (indicated by ○). That is, in the present invention (○), the deposition is performed from the initial cycle without the latent cycle, but in the prior art (●), the thin film is deposited after the latent period of 12 cycles. It can be seen that since the formation of the initial interface is deposited by a heterogeneous reaction, the aluminum oxide film is more stably formed in the case of the present invention.

10 is a graph showing the stress history according to the temperature of the aluminum oxide film formed by the conventional embodiment and the first embodiment of the present invention.

Specifically, the stress history (marked with □) of a conventional aluminum oxide film formed by using TMA as the first reactant (A) and water vapor as the second reactant (B) has a tensile stress of 450 ° C. To compress stress. In contrast, the stress history of the aluminum oxide film of the present invention formed by using TMA as the first reactant (A) and ozone as the second reactant (B) does not change the stress mode due to tensile stress in the entire temperature range. It can be seen that the membrane itself is more thermally stable.

FIG. 11 is a graph showing thickness shrinkage ratios according to post annealing conditions of aluminum oxide films formed by conventional and first exemplary embodiments of the present invention.

Specifically, on the X axis, N450, N750, and N830 are post annealing in a nitrogen atmosphere of 450 ° C, 750 ° C, and 830 ° C, respectively, and O450, O750, and O830 are 450 ° C, 750 ° C, and 830, respectively. Post annealing was carried out in an oxygen atmosphere of ℃, RTO represents a case of rapid thermal oxidation at 850 ℃. It can be seen that the thickness of the aluminum oxide film formed by the first embodiment of the prior art and the present invention is not significantly different depending on the temperature and gas conditions of the post annealing.

12 and 13 are graphs showing absorption constants and refractive indices according to wavelengths of aluminum oxide films formed by conventional and first embodiments of the present invention, respectively.

Specifically, the aluminum oxide film formed by the conventional and first embodiment of the present invention exhibits excellent transparency with an absorption constant of 0.005 or less in a wide wavelength range of 180 to 900 nm as shown in FIG. 12. In addition, it can be seen that the refractive index of the aluminum oxide film formed by the first and the first exemplary embodiments of the present invention is not significantly different in a wide wavelength range of 180 to 900 nm as shown in FIG. 13.

FIG. 14 is a graph showing wet etch rates according to post annealing temperatures and atmospheric gases of aluminum oxide films formed by conventional and first exemplary embodiments, respectively.

Specifically, as-dep on the X-axis is a sample which is not annealed after being deposited on a substrate, and N450, N750, and N830 are post annealing in a nitrogen atmosphere of 450 ° C, 750 ° C, and 830 ° C, respectively. Sample. O450, O750, and O830 are post annealing performed in an oxygen atmosphere of 450 ° C, 750 ° C and 830 ° C, respectively, and RTP represents a rapid thermal oxidation process in an oxygen atmosphere of 850 ° C. . And, the Y axis represents the etching rate when wet etching with a 200: 1 HF solution for each sample.

As shown in FIG. 14, the wet etching rate of the aluminum oxide film formed by the first embodiment of the present invention and the present invention decreases as the annealing temperature increases, regardless of the annealing conditions. In particular, when the post annealing is performed at 800 ° C. or higher, the etching rate is drastically reduced to 2-3 m / min. In addition, it can be seen that the etching rate of the aluminum oxide film according to the first embodiment of the present invention is about 30% smaller than that in the post annealing of 800 ° C. or less. It can be seen that ozone as an oxidizing gas is more chemically stable than when H ₂ O is used.

Hereinafter, the case where the aluminum oxide film formed by the first embodiment of the present invention is employed in a semiconductor element will be described.

15 is a cross-sectional view showing a capacitor structure of a semiconductor device employing a dielectric film formed by the first embodiment of the present invention.

Specifically, the capacitor of the semiconductor device employing the dielectric film formed by the first embodiment of the present invention is a substrate 201, for example, the lower electrode 205, dielectric film 207 and the upper electrode 209 formed on the silicon substrate Include. In Fig. 15, reference numeral 203 denotes an interlayer insulating film, and reference numeral 209 denotes a capping film formed on the upper electrode of the capacitor.

Hereinafter, a case where both the upper electrode 209 and the lower electrode 205 are made of a polysilicon film doped with impurities, and the dielectric film 207 is made of an aluminum oxide film formed according to the first embodiment of the present invention will be described. SIS capacitor ". The lower electrode 205 is a polysilicon film doped with impurities, the dielectric film 207 is an aluminum oxide film formed according to the first embodiment of the present invention, and the upper electrode 209 is a TiN film. The case is called "MIS capacitor". In addition, when the upper electrode 209 and the lower electrode 205 are both composed of a platinum group precious metal film such as Pt, Ru, and the like, and the dielectric film 207 is formed of an insulating film such as a tantalum oxide film or a BST (BaSrTiO ₃ ) film, Called "MIM Capacitor".

16 is a cross-sectional view showing a transistor structure of a semiconductor device employing a dielectric film formed in accordance with the first embodiment of the present invention.

Specifically, the semiconductor device employing the dielectric film according to the first embodiment of the present invention includes a silicon substrate 301 doped with impurities such as phosphorous, arsenic, boron, and fluorine as a first electrode, and a gate insulating film 305 as a dielectric film. And a gate electrode 307 as a second electrode. In Fig. 2, reference numeral 303 denotes an impurity doped region, which indicates a source or drain region.

Here, in the transistor structure of the semiconductor device of the present invention, the silicon substrate 301 corresponds to the lower electrode and the gate electrode 307 corresponds to the upper electrode as compared with the capacitor structure. The gate insulating film 305 corresponds to the dielectric film of the capacitor.

Next, for convenience of description, the insulation characteristics of the dielectric film will be described with reference to a capacitor structure, and the same applies to the transistor structure.

17 is a graph illustrating a leakage current characteristic according to an applied voltage of a conventional capacitor and a SIS capacitor employing a dielectric film formed by a first embodiment of the present invention.

Specifically, the SIS capacitor (marked with ○) of the present invention was constructed in the same manner except that the dielectric film forming method was different from the conventional capacitor (marked with?). As shown in Fig. 17, the SIS capacitor (○) of the present invention has a takeoff of about 0.4V larger than that of a conventional capacitor (●) at 1E-7A / cm ² , which is an acceptable current density in a capacitor of a general semiconductor device. Indicates take off voltage. Therefore, the SIS capacitor (○) of the present invention can lower the thickness of the dielectric film at a constant leakage current value, which is advantageous for the integration of semiconductor devices.

FIG. 18 is a graph illustrating a takeoff voltage according to an equivalent oxide film of a SIS capacitor employing a dielectric film formed according to a first embodiment of the present invention.

Specifically, the SIS capacitor according to the present invention does not reduce the take-off voltage because it shows a stable insulating property up to 35 kW equivalent oxide film thickness. When the equivalent oxide film thickness is equal to or less than 35 kV, the takeoff voltage drops rapidly and the insulation characteristic is weakened.

19 is a graph illustrating leakage current characteristics according to an applied voltage of a MIS capacitor employing a dielectric film formed according to a first embodiment of the present invention.

Specifically, in the MIS capacitor of the present invention, the thickness of the equivalent oxide film can be 26.5 kW at a general reference value of 1E-7 and a voltage of 1.2V. When the equivalent oxide film thickness is lowered, it is very advantageous for the integration of semiconductor devices.

20 is a graph comparing leakage current characteristics of a MIS capacitor employing a dielectric film formed according to a first embodiment of the present invention and a conventional capacitor.

Specifically, the conventional capacitor is the same except that the dielectric film is different compared to the MIS capacitor of the present invention. As shown in FIG. 20, the MIS capacitor employing the aluminum oxide film according to the first embodiment of the present invention is a conventional capacitor using a tantalum oxide film (TaO) or a nitride film-oxide (NO) as a dielectric film at a leakage current value of 1 fA per cell. In comparison, the applied voltage is the largest. In other words, the MIS capacitor of the present invention may have the best leakage current characteristics even in a small equivalent oxide film as compared with the conventional capacitor. In Figure 20, the numbers in parentheses indicate the thickness of the dielectric film.

21A and 21B are graphs showing leakage current characteristics according to an applied voltage when the aluminum oxide film according to the first embodiment of the present invention and the first embodiment of the present invention are used as a capping film of a MIM capacitor, respectively.

Specifically, "?" In FIGS. 21A and 21B indicates a MIM capacitor when no capping film is employed. In FIG. 21A, "?" Shows a case where an aluminum oxide film is formed by a capping film according to the prior art, and "▼" shows a case where hydrogen annealing is performed at 400 ° C after forming an aluminum oxide film as a capping film. In FIG. 21B, "●" is a case where an aluminum oxide film is formed as a capping film according to the first embodiment of the present invention, and "▲" is a case where hydrogen annealing is performed at 400 ° C after forming an aluminum oxide film as a capping film. Represents a case where nitrogen annealing is performed at 700 ° C. after forming an aluminum oxide film as a capping film.

In general, when the MIM capacitor is used in the semiconductor device, there is a problem in that the dielectric film is degraded during hydrogen annealing used in a subsequent alloy process. Accordingly, a capping film serving as a hydrogen barrier is formed on the MIM capacitor. However, when the aluminum oxide film formed according to the first embodiment of the present invention is employed as a capping film, as shown in FIG. 21A, the aluminum oxide film is formed as a capping film based on the leakage current density of 1E-7A / cm ² . Not only the case but also subsequent hydrogen annealing, the barrier properties are very good and do not deteriorate the leakage current properties. However, when the aluminum oxide film formed according to the prior art is used as a capping film as shown in FIG. 21B, hydrogen and OH ligand of water vapor deteriorate the leakage current characteristics of the MIM capacitor during the deposition process.

Second embodiment

22 is a flowchart illustrating a second embodiment of a thin film formation method using the atomic layer deposition method of the present invention.

Specifically, the substrate (15 in FIG. 3), for example, a silicon substrate is oxygen-flushed with oxidizing gas to terminate the dangling bond of the substrate 15 with oxygen (step 21). In addition to the oxygen flushing, the dangling bond may be combined with oxygen through a method such as ozone cleaning and silicon oxide film formation. In addition, oxygen flushing of the substrate 15 may not be performed if necessary.

Next, after loading the substrate 15 into the reaction chamber (11 in FIG. 3), the reaction chamber 11 is 100-400 ° C., preferably 300-350, using a heater (not shown) and a pump 19. It is maintained at a process temperature of 占 폚 and a process pressure of 1 to 10,000 mTorr (step 23). The process temperature and the process pressure may be the process temperature and the process pressure which are continuously maintained in subsequent processes, but the process temperature and the process pressure may be changed as necessary.

Subsequently, the first valve V1 is opened in the reaction chamber 11 while maintaining the process temperature and the process pressure to obtain a first reactant 11 such as trimethyl aluminum (Al (CH ₃ ) ₃ : TMA). Injecting the gas surface A and the shower head 17 for a time sufficient to cover the substrate surface, for example, from 1 m to 10 seconds (step 25). This causes the first reactant to chemisorb onto the silicon substrate flushed with oxygen.

Next, the second valve V2 is selectively opened in the reaction chamber 11 while maintaining the process temperature and the process pressure to purge an inert gas such as argon for 0.1 to 100 seconds (step 27). This removes the first reactant physically deposited on the substrate 15.

Next, the third valve V3 is opened in the reaction chamber 11 while maintaining the process temperature and the process pressure to inject an oxidizing gas containing no second reactant, such as a hydroxyl group, through the shower head 17. (Step 29). N ₂ O, O ₂ , O ₃ or CO ₂ gas may be used as the second reactant. In this case, the chemisorbed first reactant and the second reactant react to replace the first reactant with a metal-oxygen atomic layer. The second reactant is less reactive with the first reactant but can form a metal-oxygen atomic layer without generating hydroxyl groups in the metal oxide film, as described later.

Next, while maintaining the process temperature and the process pressure, the reaction chamber 11 is secondarily purged with an inert gas for 0.1 to 100 seconds to remove unnecessary reactants (step 31).

Next, an oxide such as a third reactant, for example, water vapor (H ₂ O), may open the fourth valve V3 to sufficiently cover the surface of the substrate through the shower head 17, for example, 1 m second to 10 minutes. Inject for seconds (step 33). In this case, since the third reactant is more reactive with the first reactant than the second reactant, the first reactant and the third reactant which remain unreacted in the adsorbed first reactant react and are replaced with the metal-oxygen atomic layer. . In this case, since the absolute amount of the first reactant is reduced by reacting the second reactant including the hydroxyl group with the first reactant in advance, a metal oxide film in atomic layer units in which generation of hydroxyl groups is suppressed is formed.

In the present embodiment, the metal oxide film is described as an aluminum oxide film (Al ₂ O ₃ ) as an example, the present invention is TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CeO ₂ , Y _{2 O 3, SiO 2, In 2} O 3, RuO 2, IrO 2, SrTiO 3, PbTiO 3, SrRuO 3, CaRuO 3, (Ba, Sr) TiO 3, Pb (Zr, Ti) O 3, (Pb, La (Zr, Ti) O ₃ , (Sr, Ca) RuO ₃ , (Ba, Sr) RuO ₃ , Sn doped In ₂ O ₃ (ITO), or Zr doped I ₂ O ₃ films may also be formed. .

Next, one cycle of purging the reaction chamber 11 with an inert gas for 0.1 to 100 seconds while maintaining the process temperature and the process pressure to remove unnecessary reactants to form a metal oxide film in atomic layer units. Complete (step 35). If necessary, after the third purge, a step of injecting and purging the second reactant having no hydroxyl group may be further performed to suppress the reaction of the third reactant and the first reactant as much as possible.

Then, it is confirmed whether the metal oxide film formed on the board | substrate is an appropriate thickness, for example, about 10 kV-1000 kPa (step 37). If the thickness is appropriate, the step of forming the metal oxide film is completed. If the thickness is not appropriate, the first reactant injection step (step 25) to the third purge step (step 35) are repeatedly performed.

23A to 23D are diagrams for explaining a coupling relationship of reactants adsorbed on a substrate when forming an aluminum oxide film according to the thin film formation method using the atomic layer deposition method of the second embodiment of the present invention.

Specifically, the flushing of the substrate 15, for example, the silicon substrate 15 with oxygen, is flushed with oxygen, such that the dangling bond of the substrate 15 is combined with oxygen as shown in FIG. 23A. Oxygen flushing of the substrate 15 may not be performed if necessary.

Next, trimethyl aluminum (Al (CH ₃ ) ₃ ), which is the first reactant, is injected into the reaction chamber 11 at which the process temperature of 100 to 400 ° C. and the process pressure of 1 to 10,000 mTorr are maintained, and then purged with argon gas. do. In this case, the first reactant is adsorbed onto the substrate 15 flushed with oxygen as shown in FIG. 23B. That is, there are various types such as a silicon substrate formed on the Si-O, Si-O- CH 3 or _{Si-O-Al-CH 3} .

Next, a second reactant containing no hydroxyl group, such as N ₂ O, O ₂ , O ₃ or CO ₂ , is injected into the reaction chamber 11. For example, using N ₂ O as the second reactant, the reaction formula is as follows.

2Al (CH ₃ ) ₃ + 3N ₂ O → Al ₂ O ₃ + Al (CH ₃ ) ₃ + 3C ₂ H ₆ + 3N ₂ ↑

As shown in Formula 5, when N ₂ O containing no hydroxyl group is injected into trimethyl aluminum, Al ₂ O ₃ is formed while consuming trimethyl aluminum. In other words, the adsorbed first reactant and the second reactant react to replace the first reactant with the metal-oxygen atomic layer as shown in FIG. 23C. That is, many Si-O-Al-O forms are formed on the silicon substrate.

Next, a third reactant, such as water vapor (H ₂ O), is injected into the reaction chamber and then purged with argon gas. In this case, as shown in FIG. 23D, the first reactant remaining after reacting with the second reactant in the adsorbed first reactant reacts with the third reactant to be replaced with a metal-oxygen atomic layer. In this case, since the absolute amount of the first reactant is reduced by reacting the second reactant including the hydroxyl group with the first reactant in advance, a metal oxide film in atomic layer units in which generation of hydroxyl groups is suppressed is formed.

Here, how the aluminum oxide film in atomic layer units with a small amount of hydroxyl groups are formed will be described in more detail.

First, the inventors of the present invention include Al (OH) _{3 which} is an unwanted by-product in the aluminum oxide film by the reaction as shown in Formula 2 when forming the aluminum oxide film by the conventional ALD method. In order to identify Al (OH) ₃ which is such a by-product, the present inventors performed XPS analysis of the aluminum oxide film formed by the conventional ALD method.

24 is an X-ray photoelectron spectroscopy (XPS) graph of an aluminum oxide film formed by a conventional atomic layer deposition method. In FIG. 24, the X axis represents the binding energy and the Y axis represents the count of arbitrary units.

Specifically, it can be seen that the peaks of the aluminum oxide film formed by the conventional ALD method appear slightly wider without overlapping when the graphs on the right and the left are superimposed around 535.1 eV. In other words, since the aluminum oxide film formed by the conventional ALD method contains Al (OH) ₃ , a wider graph (b) appears than a graph (a) in which a pure aluminum oxide film is formed.

In view of the above, when the reaction of trimethyl aluminum and water vapor as in the prior art, Al (OH) ₃ including a hydroxyl group is made by a reaction as shown in formula (2). Therefore, to reduce the amount of Al (OH) _{3, it} is necessary to reduce the absolute amount of trimethyl aluminum that reacts with water vapor. Therefore, in the present invention, since trimethyl aluminum is previously reacted with N ₂ O without a hydroxyl group to reduce the absolute amount of trimethyl aluminum and then reacted with water vapor, an aluminum oxide film in atomic layer units is formed with a small amount of hydroxyl groups.

25A and 25B are graphs showing leakage current characteristics of aluminum oxide films prepared by the conventional method and the second embodiment of the present invention, respectively.

Specifically, the leakage current characteristics of the aluminum oxide film were applied to the capacitor and investigated. The lower electrode of the capacitor used a polysilicon film, and the upper electrode used a polysilicon film. 25A and 25B, the first curves a and c measure the amount of current per cell flowing through the dielectric film while connecting the lower electrode to ground and the upper electrode applying a voltage from 0 to 5V, and the second curve. (b, d) is the result of measuring under the same conditions again after the first measurement. As shown in FIG. 25B, when the aluminum oxide film formed by the present invention is adopted as a dielectric film, the leakage current characteristics are shorter than the conventional voltage of FIG. It can be seen that this is improved.

Third embodiment

FIG. 26 is a flowchart illustrating a method of forming a thin film using the atomic layer deposition method according to a third embodiment of the present invention, and FIG. 27 is a reactant in forming a thin film using the atomic layer deposition method according to a third embodiment of the present invention. Is a timing diagram showing the supply of. 26 and 27, a process of forming an aluminum oxide film will be described as an example.

Specifically, the dangling bonds of the substrate 15 are terminated with oxygen or nitrogen by flushing the substrate 15, for example, the silicon substrate with nitrogen or oxygen using an oxidizing or nitriding gas (step 41). For the oxygen or nitrogen flushing, the atomic layer thin film forming apparatus as shown in FIG. 3 may be used as it is, or another apparatus may be used. In addition to the oxygen or nitrogen flushing, the dangling bond may be combined with oxygen or nitrogen through a method such as ozone cleaning, silicon oxide film, or silicon nitride film formation. In addition, oxygen or nitrogen flushing of the substrate 15 may not be performed if necessary.

Next, after loading the substrate 15 into the reaction chamber 11, the temperature of the reaction chamber 11 is 100 to 400 ° C, preferably 300 to 350 ° C using a heater (not shown) and a pump 19. And maintained at process conditions of a pressure of 1 to 10,000 mTorr (step 43). The process conditions are maintained in subsequent steps but may be changed as necessary.

Next, while maintaining the process conditions, the first valve V1 is opened in the reaction chamber 11 to obtain a metal reactant of the first reactant 11, for example, trimethyl aluminum (Al (CH ₃ ) ₃ : TMA). Injecting the gas surface A and the shower head 17 for a time sufficient to cover the substrate surface, for example, from 1 m to 10 seconds (step 45). This causes the first reactant to chemisorb onto the substrate flushed with oxygen or nitrogen.

Next, the second valve V2 is selectively opened in the reaction chamber 11 while the process conditions are maintained, and the inert gas such as argon gas is first purged for 0.1 to 100 seconds (step 47). This removes the first reactant physically deposited on the substrate 15.

Next, the third valve V3 is opened in the reaction chamber 11 while the process conditions are maintained, and the oxidation power such as the second reactant such as water vapor H ₂ O is excellent through the shower head 17. Gas is injected (step 49).

In this case, the chemisorbed first reactant and the second reactant react, and a thin film of an atomic layer unit, that is, an aluminum oxide film is formed by chemical substitution. That is, CH ₃ of TMA and H of H ₂ O react with _{each other} to remove CH ₄ , and Al of O _{2 and} O of H ₂ O react with each other to form Al ₂ O ₃ . However, since the process temperature is performed at a low temperature of 400 ° C. or lower when forming the atomic layer thin film, many impurities such as carbon or OH bond are formed in the aluminum oxide film because TMA is not completely decomposed.

Next, while maintaining the process conditions, the reaction chamber 11 is secondarily purged with an inert gas such as argon gas for 0.1 to 100 seconds to remove the unreacted and physically adsorbed second reactant (step 51). ).

Next, the reaction chamber sufficiently covers the surface of the substrate on which the thin film is formed through the fourth valve V4 and the shower head 17 with an oxidizing gas such as the third reactant for removing impurities and stoichiometric enhancement, for example, ozone. Inject for a possible time, for example, from 1 m to 10 seconds (step 53). In this case, impurities such as carbon, OH bond, and the like contained in the thin film of the atomic layer unit can be removed, and oxygen deficiency of the aluminum oxide film can be solved, thereby obtaining an excellent stoichiometric thin film.

Next, the third reaction chamber 11 is purged with an inert gas for 0.1 to 100 seconds while the process conditions are maintained to remove the unreacted and physisorbed third reactant to form a thin film of atomic layer units. Complete the cycle of (step 55).

Then, it is confirmed whether the thin film of the atomic layer unit formed on the board | substrate is a suitable thickness, for example, about 10 micrometers-1000 micrometers (step 57). If the thickness is appropriate, the step of forming the thin film is completed. If the thickness is not appropriate, the first reactant injection step (step 45) to the inert gas tertiary purge step (step 55) are repeated periodically.

In the present embodiment, the first reactant, the second reactant and the third reactant are trimethyl aluminum (Al (CH ₃ ) ₃ : TMA), which is a metal reactant, water vapor, an oxidizing gas, and an ozone gas for removing impurities and improving stoichiometry. An aluminum oxide film, which is a metal oxide film, was formed. However, when the first reactant, the second reactant, and the third reactant were respectively used as a metal reactant, TiCl ₄ , a nitride gas, NH _3, and an impurity removal and stoichiometric nitrogen gas, A phosphorus titanium nitride film can be formed.

Further, according to the thin film forming method using the atomic layer deposition method of the present invention, it is also possible to form monoatomic oxides, complex oxides, monoatomic nitrides or complex nitrides in addition to the aluminum oxide film and titanium nitride film. Examples of the monoatomic oxide include TiO ₂ , Ta ₂ O _5, ZrO ₂ , HfO ₂ , Nb ₂ O ₅ , CeO ₂ , Y ₂ O ₃ , SiO ₂ , In ₂ O ₃ , RuO ₂ or IrO ₂ . number, and examples of the complex oxide are _{SrTiO 3, PbTiO 3, SrRuO 3} , CaRuO 3, (Ba, Sr) TiO 3, Pb (Zr, Ti) O 3, (Pb.La) (Zr, Ti) O 3, (Sr, Ca) RuO _3, Sn may be mentioned doping of in ₂ O _3, Fe is doped in ₂ O ₃ or in ₂ O ₃ doped with Zr. Further, examples of the monoatomic nitride include SiN, NbN, ZrN, TaN, Ya ₃ N ₅ , AlN, GaN, WN or BN, and examples of the composite nitride include WBN, WSiN, TiSiN, TaSiN, AlSiN or AlTiN can be mentioned.

Moreover, the thin film provided by the thin film formation method using the atomic layer deposition method of this invention mentioned above can be applied to a semiconductor element. Examples thereof include a gate oxide film, an electrode of a capacitor, an anti-etching film, a reaction preventing capping film, an antireflection film during a photolithography process, a barrier metal film, a selective deposition film, a metal gate electrode, and the like.

FIG. 28 is a graph showing the thickness per cycle of an aluminum oxide film manufactured by the method for forming an atomic layer thin film of the third embodiment of the present invention.

Specifically, the X axis represents the cycle number. Here, one cycle includes injecting the first reactant, purging the physisorbed first reactant, injecting the second reactant, purging the second reactant physisorbed, injecting the third reactant and physisorbed third reactant do. In addition, the Y axis represents the thickness of the aluminum oxide film. As shown in FIG. 28, according to the thin film manufacturing method of the present invention, the aluminum oxide film is grown to a thickness of 1.1 당 per cycle, and the aluminum oxide film is formed by atomic layer deposition because the thickness increases linearly with the number of cycles. It can be seen that it is well formed.

FIG. 29 is a graph illustrating uniformity in a substrate of an aluminum oxide film manufactured by an atomic layer thin film forming method according to a third exemplary embodiment of the present invention.

Specifically, the X-axis is the center point of the 8-inch substrate, 4 points at 90-degree intervals in a circle having a radius of 1.75 inches around the center point, 90 degrees in a circle having a radius of 3.5 inches around the center point 4 points are added to represent the total 9 measurement points. The Y axis represents the thickness of the aluminum oxide film. As shown in FIG. 29, it can be seen that uniformity is very excellent in an 8-inch substrate.

30A and 30B illustrate an aluminum peak of an aluminum oxide film prepared by the method of forming an atomic layer thin film according to the prior art and the third embodiment of the present invention using x-ray photoelectron spectroscopy (XPS), respectively. It is a graph.

Specifically, the X axis represents bonding energy and the Y axis represents the number of electrons. In the conventional aluminum oxide film, as shown in FIG. 30A, Al-Al bonding appears a lot. In contrast, in the aluminum oxide film of the present invention, Al-Al bonding hardly appears and Al-O bonding mainly appears, as shown in FIG. 30B. Through this, it can be seen that the aluminum oxide film of the present invention is excellent in stoichiometry.

31A and 31B are graphs of carbon peaks of aluminum oxide films prepared by a thin film formation method using the atomic layer deposition method according to the prior art and the third embodiment of the present invention using XPS, respectively.

Specifically, the X axis represents bonding energy and the Y axis represents the number of electrons. In the conventional aluminum oxide film, a carbon peak appears as shown in FIG. 31A. This means that a large amount of carbon is contained in the aluminum oxide film. In contrast, the aluminum oxide film according to the present invention hardly exhibits a carbon peak as shown in Fig. 31B. Therefore, according to the present invention, an aluminum oxide film with reduced impurities such as carbon can be obtained.

Fourth embodiment

32 is a flowchart illustrating a method of forming an atomic layer thin film according to a fourth embodiment of the present invention. In Fig. 32, the same reference numerals as in Fig. 22 denote the same members.

Specifically, the fourth embodiment of the present invention is a method in which the second embodiment and the third embodiment are mixed. That is, after the third purge of the second embodiment, a oxidizing gas such as a fourth reactant, for example, ozone gas, is added to the reaction chamber to remove the impurities and improve the stoichiometry of the reaction chamber as in the third embodiment. The same procedure is followed except that the injection is performed for a time that can sufficiently cover the surface of the substrate on which the thin film is formed through (17), for example, from 1 m to 10 seconds (step 36a) and the fourth purge (step 36b).

In this case, impurities such as carbon, OH bond, and the like contained in the metal oxide film of the atomic layer unit can be removed, and oxygen deficiency can be solved, thereby obtaining an excellent stoichiometric thin film. In other words, the present invention is to increase the probability of reaction between the main reactants before or after the main reactants in order to improve the quality of the thin film through the removal of impurities and the more complete reaction in addition to the main reactants in forming the thin film by the atomic layer deposition method Minimize the quality of the desired thin film and byproduct concentration. In addition, the present invention uses reactants that do not generate hydroxyl groups in the reaction mechanism to reduce the concentration of byproducts in the thin film.

As described above, according to the method for forming a thin film using the atomic layer deposition method according to an embodiment of the present invention, the first reactant (A) by the binding energy difference without the transfer of radicals from the second reactant (B) to the first reactant (A) ) Ligands are separated. Then, a volatile gaseous substance is formed by the binding between the ligands, and the gaseous substance is removed by purging. As a result, the thin film formation method using the atomic layer deposition method of the present invention can reduce the impurities generated in the thin film due to side reactions because there is no movement of radicals.

In addition, according to the thin film formation method using the atomic layer deposition method according to another embodiment of the present invention, when forming the metal oxide film using the atomic layer deposition method, the first reactant is reacted with the second reactant without a hydroxyl group in advance to obtain the first reactant. By reducing the absolute amount and then reacting the first reactant with the third reactant having a hydroxyl group, it is possible to suppress the generation of by-products of the hydroxyl group in the metal oxide film. For example, in the present invention, when trimethyl aluminum is previously reacted with N ₂ O without a hydroxyl group to reduce the absolute amount of trimethyl aluminum and then reacted with water vapor, the aluminum oxide film can be formed with a small amount of hydroxyl groups.

In addition, according to the thin film formation method using the atomic layer deposition method according to another embodiment of the present invention, in addition to the first and second reactants for thin film formation to form a thin film in the reaction chamber when using the atomic layer deposition method, impurities are removed and stoichiometry is improved. Inject and purge the solvent third reactant. In this way, a thin film free of impurities and excellent in stoichiometry can be obtained.

Claims (28)

Chemically adsorbing a first reactant on the substrate by injecting a first reactant including an element and a ligand forming a thin film into a reaction chamber including a substrate; Purging the reaction chamber with an inert gas to remove the physisorbed first reactant; And Injecting a second reactant having a binding energy greater than that of the ligand in the reaction chamber into the reaction chamber to form a thin film in atomic layer units by chemical reaction of the element forming the thin film and the second reactant, and at the same time, a side reaction product. Thin film formation method using the atomic layer deposition method comprising the step of removing the ligand without the formation of. The method of claim 1, wherein the first reactant is Al (CH ₃ ) ₃ and the second reactant is an activated oxidant. The method of claim 2, wherein the activated oxidant is ozone (O ₃ ), plasma oxygen (O ₂ ), or plasma nitrogen oxide (N ₂ O). The method of claim 1, further comprising purging the chamber with an inert gas after the injection of the second reactant to remove the physically adsorbed second reactant. The method of claim 4, wherein the removing of the physisorbed second reactant is repeated a plurality of times from the injection of the first reactant. Injecting a first reactant into a reaction chamber comprising a substrate to chemisorb the first reactant onto the substrate; Purging the reaction chamber with an inert gas to remove the physisorbed first reactant; Injecting a second reactant containing no hydroxyl group into the reaction chamber to replace the chemisorbed first reactant with a metal-oxygen atomic layer; Purging the reaction chamber with an inert gas to remove the physisorbed second reactant; And Injecting a third reactant into the reaction chamber to replace the remainder of the chemisorbed first reactant with a metal-oxygen atomic layer to form a metal oxide film in atomic layer units in a state where generation of hydroxyl groups is suppressed; Thin film formation method using the atomic layer deposition method characterized in that. The method of claim 6, wherein the first reactant is a metal reactant, the second reactant without a hydroxyl group is N ₂ O, O ₂ , O ₃ or CO ₂ , characterized in that the third reactant is an oxidizing gas Thin film formation method using the atomic layer deposition method. The method of claim 6, wherein the temperature of the reaction chamber is maintained at 100 to 400 ° C. from the injection of the first reactant to the injection of the third reactant. The method of claim 6, wherein the metal oxide film is Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , CeO ₂ , Y ₂ O ₃ , SiO ₂ , In ₂ O ₃ , _{RuO 2, IrO 2, SrTiO 3} , PbTiO 3, SrRuO 3, CaRuO 3, (Ba, Sr) TiO 3, Pb (Zr, Ti) O 3, (Pb, La) (Zr, Ti) O 3, (Sr , Ca) RuO ₃ , (Ba, Sr) RuO ₃ , Sn doped In ₂ O ₃ (ITO), or Zr doped I ₂ O ₃ A thin film formation method using the atomic layer deposition method. The method of claim 6, wherein when the substrate is a silicon substrate, an oxidizing gas is injected before the first reactant is injected to terminate the dangling bond on the surface of the substrate. The method of claim 6, further comprising purging the reaction chamber with an inert gas after the third reactant injection step to remove the physisorbed third reactant. 8. The method of claim 11, wherein the removing of the physisorbed third reactant is repeated a plurality of times from the injection of the first reactant. 12. The atomic layer deposition method of claim 11, further comprising: injecting a fourth reactant into the reaction chamber for removing impurities and improving stoichiometry after removing the third physisorbed third reactant. Thin film formation method using. The method of claim 13, wherein the fourth reactant is ozone gas. Injecting a first reactant into a reaction chamber loaded with a substrate to chemisorb the first reactant onto the substrate; Purging the reaction chamber with an inert gas to remove the physisorbed first reactant; Injecting a second reactant into the reaction chamber to form a thin film of an atomic layer unit by chemical substitution of a first reactant and a second reactant; Purging the reaction chamber with an inert gas to remove the physisorbed second reactant; And A method of forming a thin film using an atomic layer deposition method comprising the step of injecting a third reactant for removing impurities and improving stoichiometry into the reaction chamber in which the thin film is formed. The method of claim 15, wherein the first reactant is a metal reactant, and the second and third reactants are an oxidizing gas. 16. The method of claim 15, wherein the thin film is a metal oxide film made of monoatomic oxide or complex oxide. The method of claim 17, wherein the monoatomic oxide is Al ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , ZrO ₂ , HfO ₂ , Nb ₂ O ₅ , CeO ₂ , Y ₂ O ₃ , SiO ₂ , In ₂ O ₃ , RuO ₂ and IrO ₂ thin film forming method using an atomic layer deposition method, characterized in that any one selected from the group consisting of. 18. The method of claim 17 wherein the composite oxide is _{SrTiO 3, PbTiO 3, SrRuO 3} , CaRuO 3, (Ba, Sr) TiO 3, Pb (Zr, Ti) O 3, (Pb.La) (Zr, Ti) O ₃ , (Sr, Ca) RuO ₃ , an atomic layer selected from the group consisting of Sn doped In ₂ O ₃ , Fe doped In ₂ O ₃ and Zr doped In ₂ O ₃ Thin film formation method using the vapor deposition method. The method of claim 15, wherein the first reactant is a metal reactant, and the second and third reactants are a nitriding gas. 16. The method of claim 15, wherein the thin film is a metal nitride film made of monoatomic nitride or composite nitride. The method of claim 21, wherein the monoatomic nitride is any one selected from the group consisting of SiN, NbN, ZrN, TiN, TaN, Ya ₃ N ₅ , AlN, GaN, WN and BN using the atomic layer deposition method Thin film formation method. The method of claim 21, wherein the composite nitride is any one selected from the group consisting of WBN, WSiN, TiSiN, TaSiN, AlSiN, and AlTiN. 16. The method of claim 15, further comprising purging the reaction chamber with an inert gas after the third reactant injection step to remove the physically adsorbed third reactant. The thin film using the atomic layer deposition method of claim 15, wherein when the substrate is a silicon substrate, an oxidizing gas or a nitride gas is further injected before the first reactant is injected to terminate the dangling bond on the surface of the substrate. Forming method. The method of claim 15, wherein the temperature of the reaction chamber is maintained at 100 to 400 ° C. from the injection of the first reactant to the injection of the third reactant. 16. The method of claim 15, further comprising purging the reaction chamber with an inert gas after the third reactant injection step to remove the physically adsorbed third reactant. 28. The method of claim 27, wherein the removing of the physisorbed third reactant is repeated a plurality of times from the injection of the first reactant.