Substrate processing method
By forming aluminum-doped diffusion barriers between aluminum oxide and high dielectric constant thin films, the method addresses aluminum diffusion issues, enhancing the electrical performance of semiconductor devices by preventing leakage current and maintaining film thickness.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- WONIK IPS CO LTD
- Filing Date
- 2025-12-08
- Publication Date
- 2026-07-02
AI Technical Summary
The diffusion of aluminum from aluminum oxide films into high-dielectric thin films during annealing or high-temperature processes in semiconductor devices leads to deteriorated electrical characteristics due to increased leakage current, particularly in metal-insulator-metal capacitors used in DRAM devices.
A substrate treatment method involving the formation of a pair of high dielectric constant thin films, such as zirconium or hafnium oxide, with an aluminum-doped diffusion barrier film interposed between the aluminum oxide film to prevent aluminum diffusion and maintain electrical integrity.
The method effectively prevents aluminum diffusion, maintaining the physical thickness and leakage current blocking performance of the aluminum oxide film, thereby improving the electrical characteristics of semiconductor devices.
Smart Images
Figure KR2025020964_02072026_PF_FP_ABST
Abstract
Description
Substrate processing method
[0001] The present invention relates to a substrate treatment method, and more specifically, to a substrate treatment method for improving the electrical characteristics of a semiconductor device having a pair of high dielectric constant thin films interposed between oxide films.
[0002] As the integration density of semiconductor devices increases, the area in which the device is implemented is gradually decreasing. However, in the case of semiconductor memory devices, such as DRAM devices, a minimum required capacitance must be secured even if the device area is reduced. Depending on the junction structure, capacitors include MOS structures, PN junction structures, polysilicon-insulator-polysilicon (PIP) structures, or metal-insulator-metal (MIM) structures. In applications requiring high-speed capacitors, metal-insulator-metal (MIM) capacitors are mainly used because they allow for the easy realization of low-resistance capacitor electrodes. Metal-insulator-metal capacitors are formed using metal films as the bottom and top electrodes, and as the dielectric film, a thin film made of a high-dielectric constant (high-k) material is applied to the capacitor portion to increase the capacity of DRAM. For example, a pair of high-dielectric thin films (zirconium oxide or hafnium oxide) interposed between aluminum oxide films are utilized as dielectric films; however, as aluminum diffuses from the aluminum oxide film into the high-dielectric thin films during subsequent annealing or high-temperature processes, a problem arises in which electrical characteristics deteriorate due to leakage current. Korean Published Patent No. 10-2006-0017452 serves as a prior art document.
[0003] The present invention aims to provide a substrate processing method capable of forming a high dielectric constant thin film structure capable of improving electrical characteristics according to leakage current so as to be applied to a capacitor of a DRAM device.
[0004] However, these tasks are exemplary and do not limit the scope of the invention.
[0005] According to one aspect of the present invention, a substrate treatment method is provided. The substrate treatment method comprises the steps of forming a pair of high dielectric constant thin films on a substrate, with an aluminum oxide film interposed between them, and forming a diffusion barrier film doped with aluminum between the aluminum oxide film and the high dielectric constant thin film to prevent aluminum from diffusing from the aluminum oxide film to the high dielectric constant thin film.
[0006] In the above substrate processing method, the pair of high dielectric constant thin films may be a pair of zirconium oxide films or a pair of hafnium oxide films.
[0007] In the above substrate processing method, the aluminum-doped diffusion barrier film may be an aluminum-doped zirconium oxide film or an aluminum-doped hafnium oxide film.
[0008] In the above substrate treatment method, the aluminum-doped zirconium oxide film can be formed by performing a unit cycle at least once, which includes the steps of adsorbing a zirconium-containing precursor, a first purge step, adsorbing an aluminum-containing precursor, a second purge step, and supplying a reaction gas containing oxygen.
[0009] In the above substrate processing method, the aluminum-doped hafnium oxide film can be formed by performing a unit cycle at least once, which includes the steps of adsorbing a precursor containing hafnium, a first purge step, adsorbing a precursor containing aluminum, a second purge step, and supplying a reaction gas containing oxygen.
[0010] In the above substrate processing method, the pair of high dielectric constant thin films consists of a first high dielectric constant thin film under the aluminum oxide film and a second high dielectric constant thin film on the aluminum oxide film, and the aluminum-doped diffusion barrier film can be formed between the first high dielectric constant thin film and the aluminum oxide film.
[0011] In the above substrate processing method, the pair of high dielectric constant thin films consists of a first high dielectric constant thin film under the aluminum oxide film and a second high dielectric constant thin film on the aluminum oxide film, and the aluminum-doped diffusion barrier film can be formed between the first high dielectric constant thin film and the aluminum oxide film and between the second high dielectric constant thin film and the aluminum oxide film, respectively.
[0012] In the above substrate processing method, the step of forming a pair of high dielectric constant thin films interposed between the aluminum oxide film and the step of forming the aluminum-doped diffusion barrier film can be performed in-situ.
[0013] According to one embodiment of the present invention as described above, a substrate processing method can be implemented to form a high dielectric constant thin film structure capable of improving electrical characteristics according to leakage current so as to be applied to a capacitor of a DRAM device.
[0014] Of course, the scope of the present invention is not limited by these effects.
[0015] FIG. 1 is a macroscopic illustration of a substrate processing method according to a comparative example of the present invention, and FIG. 2 is a microscopic illustration of a substrate processing method according to a comparative example of the present invention.
[0016] FIGS. 3 and 4 are macroscopic drawings illustrating a substrate processing method according to embodiments of the present invention, and FIGS. 5 to 8 are microscopic drawings illustrating a substrate processing method according to embodiments of the present invention in sequence.
[0017] Figures 9 and 10 are transmission electron microscope (TEM) images and electron energy loss spectroscopy (EELS) analysis images of a specimen according to the first experimental example of the present invention, respectively.
[0018] Figure 11 is a graph showing the leakage current and oxide thickness of a device implemented by the substrate treatment method according to the second experimental example of the present invention.
[0019] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
[0020] Throughout the specification, when it is stated that one component, such as a film, region, or substrate, is located "on" another component, it may be interpreted that the one component is in direct contact "on" the other component, or that other components may exist interposed therebetween. On the other hand, when it is stated that one component is located "directly on" another component, it is interpreted that no other components interposed therebetween exist.
[0021] Hereinafter, embodiments of the present invention are described with reference to drawings that schematically illustrate ideal embodiments of the present invention. In the drawings, variations of the depicted shapes may be expected, for example, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the inventive concept should not be interpreted as being limited to specific shapes of the areas depicted herein, but should include, for example, variations in shape resulting from manufacturing. Additionally, the thickness or size of each layer in the drawings may be exaggerated for convenience and clarity of explanation. Identical reference numerals denote identical elements.
[0022] Meanwhile, the terms AlO, ZrO, and HfO in this specification and drawings refer to aluminum oxide (e.g., Al2O3), zirconium oxide (e.g., ZrO2), and hafnium oxide (e.g., HfO2), respectively; these are merely stylistic representations and do not imply the precise stoichiometric or chemical formulas constituting the actual thin films.
[0023] FIG. 1 is a macroscopic illustration of a substrate processing method according to a comparative example of the present invention, and FIG. 2 is a microscopic illustration of a substrate processing method according to a comparative example of the present invention.
[0024] Referring to FIG. 1 (a), an aluminum oxide film (14) forms a pair of high dielectric constant films (12) interposed between them. The high dielectric constant films (12) may be made of zirconium oxide or hafnium oxide. The pair of high dielectric constant films (12) may consist of a first high dielectric constant film (12a) under the aluminum oxide film (14) and a second high dielectric constant film (12b) on the aluminum oxide film (14).
[0025] Referring to FIG. 1(b), when a subsequent process such as annealing or a high-temperature process is performed on a pair of high-dielectric thin films (12) interposed between an aluminum oxide film (14), aluminum diffuses from the aluminum oxide film (14) to the high-dielectric thin film (12) to form a predetermined diffusion layer (16; 16a, 16b). If the high-dielectric thin film (12) is a zirconium oxide film, the diffusion layer (16) may be a ZrAlOx film, and if the high-dielectric thin film (12) is a hafnium oxide film, the diffusion layer (16) may be an HfAlOx film.
[0026] Referring to Figure 2(a), for example, the high dielectric constant film (12), which is a zirconium oxide film, has many empty spaces within the crystal.
[0027] Referring to FIG. 2(b), when a subsequent process such as annealing or a high-temperature process is performed on a structure in which a high dielectric constant thin film (12) and an aluminum oxide film (14) are placed adjacently, the aluminum constituting the aluminum oxide film (14) diffuses into the empty space (circle indicated by a dotted line) within the crystal of the high dielectric constant thin film (12) to form a diffusion layer (16).
[0028] The diffusion layer (16) can be understood to include at least a portion of the region formed by the diffusion of aluminum, including the interface between the high dielectric constant film (12) and the aluminum oxide film (14). If the high dielectric constant film (12) is a zirconium oxide film, the diffusion layer (16) may be a ZrAlOx film, and if the high dielectric constant film (12) is a hafnium oxide film, the diffusion layer (16) may be an HfAlOx film.
[0029] The aluminum oxide film (14) introduced to block leakage current may have a problem in which its physical thickness decreases due to the diffusion of aluminum and the density of the film decreases, thereby deteriorating the leakage current blocking characteristics.
[0030] To explain from another perspective, if a subsequent process such as annealing or a high-temperature process is performed on a ZrO-AlO-ZrO stacked structure, concentration diffusion occurs within the film and a diffusion layer (16) in which ZrO and AlO are mixed in a disordered manner is formed, which may degrade the leakage current blocking performance of the aluminum oxide film (14).
[0031] FIGS. 3 and 4 are macroscopic drawings illustrating a substrate processing method according to embodiments of the present invention, and FIGS. 5 to 8 are microscopic drawings illustrating a substrate processing method according to embodiments of the present invention in sequence.
[0032] Referring to FIGS. 3 to 8, a substrate treatment method according to an embodiment of the present invention includes the steps of forming a pair of high dielectric constant thin films (12) interposed between an aluminum oxide film (14) on a substrate (not shown), and forming a diffusion barrier film (18) doped with aluminum between the aluminum oxide film (14) and the high dielectric constant thin film (12) to prevent aluminum from diffusing from the aluminum oxide film (14) to the high dielectric constant thin film (12).
[0033] In the above substrate processing method, the step of forming a pair of high dielectric constant thin films (12) interposed between the aluminum oxide film (14) and the step of forming the aluminum-doped diffusion barrier film (18) can be performed in-situ.
[0034] Performing the above-described steps in-situ may mean performing all of the above-described steps within a single process chamber without interrupting the vacuum atmosphere (vacuum break) while maintaining the vacuum level within a predetermined range, or performing all of the above-described steps within a single substrate processing apparatus composed of multiple process chambers while maintaining the vacuum level within a predetermined range without interrupting the vacuum state.
[0035] In the process of performing the aforementioned steps, if a portion is performed in one facility and the remainder in another, the vacuum state is interrupted and inevitably exposed to the atmosphere, resulting in deterioration of the thin film quality and the formation of an unintended native oxide.
[0036] The above pair of high dielectric constant thin films (12) may be a pair of zirconium oxide films (ZrO) or a pair of hafnium oxide films (HfO). The above aluminum-doped diffusion barrier film (18) may be an aluminum-doped zirconium oxide film (Al-doped ZrO) or an aluminum-doped hafnium oxide film (Al-doped HfO).
[0037] Referring to FIG. 3, in a substrate processing method according to one embodiment of the present invention, the pair of high dielectric constant thin films (12) are composed of a first high dielectric constant thin film (12a) under the aluminum oxide film (14) and a second high dielectric constant thin film (12b) on the aluminum oxide film (14). The aluminum-doped diffusion barrier film (18) is composed of a first diffusion barrier film (18a) formed between the first high dielectric constant thin film (12a) and the aluminum oxide film (14), and a second diffusion barrier film (18b) formed between the second high dielectric constant thin film (12b) and the aluminum oxide film (14).
[0038] A substrate processing method according to one embodiment of the present invention may include the steps of forming a first high dielectric constant thin film (12a) on a substrate, forming a first diffusion barrier film (18a) on the first high dielectric constant thin film (12a), forming an aluminum oxide film (14) on the first diffusion barrier film (18a), forming a second diffusion barrier film (18b) on the aluminum oxide film (14), and forming a second high dielectric constant thin film (12b) on the second diffusion barrier film (18b).
[0039] Referring to FIG. 4, in a substrate processing method according to another embodiment of the present invention, the pair of high dielectric constant thin films (12) are composed of a first high dielectric constant thin film (12a) under the aluminum oxide film (14) and a second high dielectric constant thin film (12b) on the aluminum oxide film (14). The aluminum-doped diffusion barrier film (18) is composed of a first diffusion barrier film (18a) formed between the first high dielectric constant thin film (12a) and the aluminum oxide film (14).
[0040] A substrate treatment method according to another embodiment of the present invention may include the steps of forming a first high dielectric constant thin film (12a) on a substrate, forming a first diffusion barrier film (18a) on the first high dielectric constant thin film (12a), forming an aluminum oxide film (14) on the first diffusion barrier film (18a), and forming a second high dielectric constant thin film (12b) on the aluminum oxide film (14).
[0041] A substrate processing method according to an embodiment of the present invention will be explained with reference to FIGS. 5 to 8, which are drawings illustrating the method in microscopic order. For convenience of explanation, the high dielectric constant thin film (12) is assumed to be, for example, a zirconium oxide film.
[0042] First, referring to FIG. 5, the high dielectric constant thin film (12), which is a zirconium oxide film, has many empty spaces within the crystal.
[0043] Referring to FIG. 6, in order to form a diffusion barrier (18) on a high dielectric constant thin film (12), the steps of adsorbing a zirconium-containing precursor, a first purging step of purging the zirconium-containing precursor that is not adsorbed and remains, adsorbing an aluminum-containing precursor, and a second purging step of purging the aluminum-containing precursor that is not adsorbed and remains is performed sequentially. Accordingly, the empty space within the crystal described in FIG. 5 is filled with aluminum derived from the aluminum-containing precursor.
[0044] Referring to FIG. 7, after the second purging step, a step of supplying a reaction gas containing oxygen (e.g., O3) is performed. Accordingly, a diffusion barrier (18) is formed on the high dielectric constant thin film (12). If the high dielectric constant thin film (12) is a zirconium oxide film, the diffusion barrier (18) may be an aluminum-doped zirconium oxide film (Al-doped ZrO).
[0045] That is, the aluminum-doped zirconium oxide film (Al-doped ZrO) as the diffusion barrier (18) can be formed by performing a unit cycle at least once, which includes the steps of adsorbing a zirconium-containing precursor, a first purging step, adsorbing an aluminum-containing precursor, a second purging step, and supplying a reaction gas containing oxygen. In this case, the diffusion barrier (18) can be understood as a zirconium oxide film that is fully doped with aluminum, and as a diffusion barrier in which aluminum is saturated within the zirconium oxide film.
[0046] Meanwhile, although not shown in the drawing, an aluminum-doped hafnium oxide film (Al-doped HfO) as a diffusion barrier (18) can be formed by performing a unit cycle at least once, which includes the steps of adsorbing a precursor containing hafnium, a first purging step, adsorbing a precursor containing aluminum, a second purging step, and supplying a reaction gas containing oxygen. In this case, the diffusion barrier (18) can be understood as a hafnium oxide film that is fully doped with aluminum, and as a diffusion barrier in which aluminum is saturated within the hafnium oxide film.
[0047] Referring to FIG. 8, an aluminum oxide film (14) can be formed on the diffusion barrier (18).
[0048] According to the substrate treatment method according to the embodiment of the present invention described above, a diffusion barrier film (18) saturated with aluminum and sufficiently doped with aluminum is pre-interposed between the aluminum oxide film (14) and the high dielectric constant film (12), thereby preventing the phenomenon of aluminum diffusing from the aluminum oxide film (14) to the high dielectric constant film (12), and thereby preventing physical thickness loss of the aluminum oxide film (14) and reducing leakage current of the semiconductor device.
[0049] To explain from another perspective, when performing a subsequent process such as annealing or a high-temperature process on an existing ZrO-AlO-ZrO stacked structure, the phenomenon in which aluminum diffuses from the aluminum oxide film (14) and the leakage current blocking performance of the aluminum oxide film (14) deteriorates can be prevented by the mechanism described above. That is, to prevent the concentration diffusion of aluminum, a diffusion barrier film (18), which is a zirconium oxide film saturated with aluminum, can be formed in advance at the interface between the aluminum oxide film (14) and the high dielectric constant thin film (12), which is a zirconium oxide film, thereby preventing the concentration diffusion of aluminum. Furthermore, by introducing an aluminum-doped zirconium oxide film (Al-doped ZrO) as a diffusion barrier (18), the interfacial coherency between the aluminum oxide film (14) and the high dielectric constant thin film (12), which is a zirconium oxide film, is improved, and the phenomenon of physical thickness loss compared to the actual deposition cycle due to the accumulation of aluminum or aluminum oxide in the internal empty space of the high dielectric constant thin film (12), which is a zirconium oxide film, can also be improved.
[0050] Hereinafter, the structure and operation of the present invention will be explained in more detail through preferred embodiments and comparative examples. However, these are presented as merely examples of the present invention and should not be interpreted in any way as limiting the present invention. Details not described herein can be sufficiently technically inferred by those skilled in the art, so such descriptions are omitted.
[0051] Experimental Example 1
[0052] FIGS. 9 and FIGS. 10 are transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS) analysis images of a specimen according to the first experimental example of the present invention, respectively. In particular, FIG. 10 applies the TEM-EELS (Transmission Electron Microscopy - Electron Energy Loss Spectroscopy) analysis technique, which simultaneously analyzes the structural and chemical properties of a material at the nanometer level.
[0053] A comparative example of the first experimental example corresponds to the case in which, in the structure shown in FIG. 1, the first high dielectric constant film (12a) and the second high dielectric constant film (12b) are each zirconium oxide films with a thickness of 30 Å, and the thickness of the aluminum oxide film (14) interposed between the pair of high dielectric constant films (12) is 20 Å, corresponding to the left photograph (a) of FIG. 9 and FIG. 10.
[0054] The invention example of the first experimental example corresponds to the case in which, in the structure shown in FIG. 3, the first high dielectric constant film (12a) and the second high dielectric constant film (12b) are each zirconium oxide films with a thickness of 28 Å, the aluminum oxide film (14) interposed between the pair of high dielectric constant films (12) has a thickness of 20 Å, and the first diffusion barrier film (18a) formed between the first high dielectric constant film (12a) and the aluminum oxide film (14) and the second diffusion barrier film (18b) formed between the second high dielectric constant film (12b) and the aluminum oxide film (14) are each aluminum-saturated doped zirconium oxide films (Al-doped ZrO) with a thickness of 2 Å, corresponding to the right photograph (b) of FIG. 9 and FIG. 10.
[0055] Referring to FIGS. 9 and 10, it can be seen that in the comparative example, the density of the aluminum oxide film (14) is low and the physical thickness is low. Additionally, when the aluminum oxide film (14) is deposited on the zirconium oxide film, which is a high dielectric constant thin film (12) in the comparative example, it can be seen that a loss is induced in the deposition cycle of the aluminum oxide film (14) because aluminum fills the empty spaces of the zirconium oxide film during deposition. According to electron energy loss spectroscopy (EELS) analysis for zirconium and aluminum, it can be seen that diffusion within the film is more pronounced in the comparative example. In the aluminum-doped zirconium oxide film (Al-doped ZrO) according to the inventive example, a clear boundary between the films is observed compared to the comparative example, and in particular, a difference in diffusivity is clearly observed in the zirconium / aluminum single electron energy loss spectroscopy (EELS) analysis (the diffusion of zirconium into the empty spaces within the aluminum oxide film is prominent). In the example of the invention, it can be confirmed that in the aluminum-doped zirconium oxide film (Al-doped ZrO), aluminum is normally adsorbed and deposited as a doping layer after zirconium is adsorbed.
[0056] Experimental Example 2
[0057] Figure 11 is a graph showing the leakage current (vertical axis) and oxide thickness (horizontal axis) of a device implemented by the substrate processing method according to the second experimental example of the present invention.
[0058] E OT Equivalent Oxide Thickness is an important concept in semiconductor devices and is an indicator representing the thickness of the oxide. OT refers not to the actual oxide thickness, but to the "equivalent thickness" that enables the insulator to possess insulating properties similar to actual silicon oxide (SiO2). Since high-dielectric materials (e.g., HfO₂, ZrO₂, etc.) have a higher dielectric constant than SiO₂, they can be used at thinner thicknesses to obtain the same electrical characteristics. E OT is T ox(Actual oxide thickness) and the dielectric constant of silicon oxide (ε ox The product of ) is the permittivity (ε) of the high-dielectric thin film high-k It corresponds to the value divided by ).
[0059] In the second experimental example, experimental example 1 (#1) corresponds to the case where, in the structure shown in FIG. 1, the first high dielectric constant thin film (12a) and the second high dielectric constant thin film (12b) are each zirconium oxide films with a thickness of 30 Å, and the thickness of the aluminum oxide film (14) interposed between the pair of high dielectric constant thin films (12) is 3 Å.
[0060] In the second experimental example, experimental example 2 (#2) corresponds to the case where, in the structure shown in FIG. 3, the first high dielectric constant film (12a) and the second high dielectric constant film (12b) are each zirconium oxide films with a thickness of 29 Å, the aluminum oxide film (14) interposed between the pair of high dielectric constant films (12) has a thickness of 3 Å, and the first diffusion barrier film (18a) formed between the first high dielectric constant film (12a) and the aluminum oxide film (14) and the second diffusion barrier film (18b) formed between the second high dielectric constant film (12b) and the aluminum oxide film (14) are each aluminum-saturated doped zirconium oxide films (Al-doped ZrO) with a thickness of 1 Å.
[0061] In the second experimental example, experimental example 3 (#3) corresponds to the case in which, in the structure shown in FIG. 4, the first high dielectric constant film (12a) is a zirconium oxide film with a thickness of 27 Å, the second high dielectric constant film (12b) is a zirconium oxide film with a thickness of 30 Å, the aluminum oxide film (14) interposed between the pair of high dielectric constant films (12) has a thickness of 3 Å, and the first diffusion barrier film (18a) formed between the first high dielectric constant film (12a) and the aluminum oxide film (14) is an aluminum-saturated doped zirconium oxide film (Al-doped ZrO) with a thickness of 2 Å.
[0062] In the second experimental example, experimental example 4 (#4) corresponds to the case where, in the structure shown in FIG. 3, the first high dielectric constant film (12a) and the second high dielectric constant film (12b) are each zirconium oxide films with a thickness of 28 Å, the aluminum oxide film (14) interposed between the pair of high dielectric constant films (12) has a thickness of 3 Å, and the first diffusion barrier film (18a) formed between the first high dielectric constant film (12a) and the aluminum oxide film (14) and the second diffusion barrier film (18b) formed between the second high dielectric constant film (12b) and the aluminum oxide film (14) are each aluminum-saturated doped zirconium oxide films (Al-doped ZrO) with a thickness of 2 Å.
[0063] When comparing Experimental Example 1 (#1) and Experimental Example 2 (#2), the leakage current characteristics are slightly improved, and E OT It can be confirmed that the characteristics are slightly degraded. It is determined that a thickness of 1 Å of the aluminum-saturated doped zirconium oxide film (Al-doped ZrO) as a diffusion barrier (18) is insufficient, and the interface between the second high dielectric constant film (12b) and the aluminum oxide film (14) inhibits the template effect of the second high dielectric constant film (12b), E OT It is determined that the characteristics have deteriorated.
[0064] When comparing Experimental Example 1 (#1) and Experimental Example 4 (#4), the leakage current characteristics are significantly improved, and E OT It can be confirmed that the characteristics are significantly degraded. Although the thickness of the aluminum-saturated doped zirconium oxide film (Al-doped ZrO) as a diffusion barrier (18) is very effective, due to the crystallization deterioration of the second high dielectric constant thin film (12b), E OT It is determined that the characteristics have deteriorated.
[0065] When comparing Experimental Example 1 (#1) and Experimental Example 3 (#3), the leakage current characteristics are significantly improved, and E OTIt can be confirmed that the characteristics are slightly improved. The thickness of 2 Å of the aluminum-saturated doped zirconium oxide film (Al-doped ZrO) as the diffusion barrier (18) is very effective, and does not hinder the crystallization of the second high dielectric constant film (12b), and also prevents the diffusion of the first high dielectric constant film (12a), E OT The characteristics are also slightly improved.
[0066] When comparing Experimental Example 3 (#3) and Experimental Example 4 (#4), since the second diffusion barrier (18b) is introduced during the process of forming the second high dielectric constant thin film (12b) on the aluminum oxide film (14), the influence of the aluminum-saturated doped zirconium oxide film (Al-doped ZrO) is not significant, and the degree of crystallization inhibition increases, E OT The characteristics deteriorate.
[0067] The present invention has been described with reference to an embodiment illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.
Claims
1. A step of forming a pair of high dielectric constant thin films on a substrate, with an aluminum oxide film interposed between them; and A step comprising: forming an aluminum-doped diffusion barrier between the aluminum oxide film and the high dielectric constant film to prevent aluminum from diffusing from the aluminum oxide film to the high dielectric constant film; Substrate processing method.
2. In Paragraph 1, The above pair of high dielectric constant thin films is characterized as being a pair of zirconium oxide films or a pair of hafnium oxide films. Substrate processing method.
3. In Paragraph 2, The above aluminum-doped diffusion barrier is characterized in that it is an aluminum-doped zirconium oxide film or an aluminum-doped hafnium oxide film. Substrate processing method.
4. In Paragraph 3, The above aluminum-doped zirconium oxide film is characterized by being formed by performing a unit cycle at least once, comprising: a step of adsorbing a zirconium-containing precursor; a first purging step; a step of adsorbing an aluminum-containing precursor; a second purging step; and a step of supplying a reaction gas containing oxygen. Substrate processing method.
5. In Paragraph 3, The above aluminum-doped hafnium oxide film is characterized by being formed by performing a unit cycle at least once, comprising: a step of adsorbing a precursor containing hafnium; a first purging step; a step of adsorbing a precursor containing aluminum; a second purging step; and a step of supplying a reaction gas containing oxygen. Substrate processing method.
6. In Paragraph 1, The above pair of high dielectric constant thin films consists of a first high dielectric constant thin film under the aluminum oxide film and a second high dielectric constant thin film on the aluminum oxide film, and The above aluminum-doped diffusion barrier is characterized by being formed between the first high dielectric constant thin film and the aluminum oxide film. Substrate processing method.
7. In Paragraph 1, The above pair of high dielectric constant thin films consists of a first high dielectric constant thin film under the aluminum oxide film and a second high dielectric constant thin film on the aluminum oxide film, and The aluminum-doped diffusion barrier is characterized by being formed between the first high dielectric constant thin film and the aluminum oxide film and between the second high dielectric constant thin film and the aluminum oxide film, respectively. Substrate processing method.
8. In Paragraph 1, The step of forming a pair of high dielectric constant thin films interposed between the aluminum oxide film and the step of forming the aluminum-doped diffusion barrier film are characterized by being performed in-situ. Substrate processing method.