Method for regulating and controlling ferroelectricity of hafnium oxide-based material

Abstract

The invention discloses a method for regulating and controlling the ferroelectricity of a hafnium oxide-based material, which comprises the following steps of: injecting plasma into a region with the ferroelectricity to be regulated and controlled on a hafnium oxide-based material layer, and carrying out annealing treatment to obtain the hafnium oxide-based material layer after the ferroelectricity is regulated and controlled. Plasma is injected into the hafnium oxide-based material layer, the plasma reduces the oxygen vacancy concentration after occupying the oxygen vacancy of the hafnium oxide-based material, and in the annealing process, the plasma is compounded with the oxygen vacancy, so that the ferroelectricity of the hafnium oxide-based material is reduced or eliminated. According to the method, the ferroelectricity of the material can be precisely and selectively defined, so that the hafnium oxide-based material can be used as an ideal gate oxide material. Therefore, the method provided by the invention can effectively reduce or eliminate ferroelectricity of the hafnium oxide-based material.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductors and integrated circuits, and particularly relates to a method for regulating the ferroelectricity of hafnium oxide-based materials by plasma implantation. Background Art

[0002] Hafnium oxide (HfO2)-based ferroelectric memories have attracted much attention due to their many excellent properties, including low operating voltage, good CMOS compatibility, and excellent scalability. Therefore, hafnium oxide-based ferroelectric materials can be used for ferroelectric memories in next-generation DRAMs or FeFETs for storage and in-memory computing applications. Hafnium oxide-based ferroelectric materials mainly form ferroelectricity after rapid annealing after being prepared by deposition techniques such as atomic deposition or physical vapor deposition. They can be used as the gate oxide material of FeFETs or as the dielectric material of FeCAP ferroelectric capacitors in FeRAMs. However, designing the process flow of ferroelectric devices is challenging. In the prior art, using deposition techniques usually results in the hafnium oxide-based material layer covering the entire wafer surface, leading to unnecessary ferroelectricity at the gate. However, when depositing hafnium oxide-based ferroelectric materials and other materials on the same plane, conflicts will occur in the manufacturing process, such as the gate oxide required for the gate oxide of FeFETs and the normal select-gate FET, or the gate oxide layer of FETs and the ferroelectric layer of ferroelectric capacitors. Currently, it is usually to deposit hafnium oxide-based materials first and then anneal to form ferroelectricity, and then remove all unnecessary parts, and then regrow a new high-K gate oxide material as the gate oxide of the normal select-gate FET, and then remove the high-K gate oxide material deposited on the hafnium oxide-based ferroelectric material. This process is not only cumbersome, but also requires strict control of the etching method, and the etching (removal) of the material itself will also make the channel interface worse, further affecting the performance of ferroelectric devices. Therefore, there is an urgent need for an effective method to regulate the ferroelectricity of hafnium oxide-based materials to simplify the manufacturing method of ferroelectric devices and save energy and materials. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art to some extent. For this purpose, the present invention provides a method for regulating the ferroelectricity of hafnium oxide-based materials. The method of the present invention can effectively reduce or remove the ferroelectricity of hafnium oxide-based materials, better optimize the requirements for different properties such as dielectricity and ferroelectricity in the same plane, reduce the manufacturing steps of ferroelectric devices, and play a role in saving energy and materials.

[0004] Therefore, in the first aspect of the present invention, the present invention proposes a method for regulating the ferroelectricity of hafnium oxide-based materials, including:

[0005] Injecting plasma into the region to be regulated of the ferroelectricity on the hafnium oxide-based material layer, and after annealing treatment, obtaining a hafnium oxide-based material layer with regulated ferroelectricity.

[0006] The method of the present invention can selectively inject plasma into the hafnium oxide-based material layer. The plasma reduces the oxygen vacancy concentration by occupying the oxygen vacancies in the hafnium oxide-based material. During the annealing process, the plasma recombines with the oxygen vacancies, thereby reducing or eliminating the ferroelectricity of the hafnium oxide-based material. Moreover, the lower the oxygen vacancy concentration, the weaker the ferroelectricity. By this method, the ferroelectricity of the material can be precisely and selectively defined, enabling the hafnium oxide-based material to be used as an ideal gate oxide material. Thus, the method of the present invention can effectively reduce or eliminate the ferroelectricity of the hafnium oxide-based material.

[0007] In some embodiments, the chemical general formula of the hafnium oxide-based material is Hf 1-x M x O2, where M represents a doping element, and M is selected from at least one of Zr, Al, La, Si, Sr, Mg, Y, Gd, and 0.01 ≤ x ≤ 0.99.

[0008] In some embodiments, the plasma includes oxygen plasma.

[0009] In some embodiments, in the step of injecting plasma into the region on the hafnium oxide-based material layer whose ferroelectricity is to be regulated, the method of generating the plasma includes using at least one of inductively coupled plasma etching technology, electron cyclotron resonance technology, and capacitively coupled plasma technology.

[0010] In some embodiments, in the inductively coupled plasma etching technology, the control parameters are: the time is 10 - 40 s, and the power is 400 - 600 W.

[0011] In some embodiments, the step of injecting plasma into the region on the hafnium oxide-based material layer whose ferroelectricity is to be regulated includes:

[0012] Cover the hafnium oxide-based material layer with a patterned mask, and inject plasma into the exposed area of the mask.

[0013] In some embodiments, it includes:

[0014] Form a coating of photoresist on the hafnium oxide-based material layer to cover the expected ferroelectric region;

[0015] Remove the coating in the exposed area of the mask and inject plasma;

[0016] Remove the coating in the expected ferroelectric region.

[0017] In some embodiments, the photoresist includes positive photoresist.

[0018] In the second aspect of the present invention, the present invention proposes a method for preparing a ferroelectric device, including the method of the first aspect, as well as thin film deposition, photolithography, etching, and photoresist removal.

[0019] Thus, the method for preparing the ferroelectric device of the present invention has the advantages of simplicity, high efficiency, energy conservation, and material reduction.

[0020] In the third aspect of the present invention, a ferroelectric device is proposed, which includes the ferroelectric device obtained by the preparation method of the second aspect, or includes the ferroelectric device processed by the method of the first aspect.

[0021] Thus, the ferroelectric capacitor region of the ferroelectric device of the present invention has excellent ferroelectric properties, and excellent dielectric properties in the gate oxide region and other regions.

[0022] Compared with the prior art, the beneficial technical effects achieved by the present invention are as follows:

[0023] Based on the characteristic that the ferroelectricity of hafnium oxide-based materials is strongly correlated with the oxygen vacancy concentration in the material, the present invention increases the concentration of oxygen elements in the material by means of plasma implantation, and makes oxygen atoms recombine with oxygen vacancies during the rapid annealing process to reduce ferroelectricity or even almost eliminate ferroelectricity. By this method, the ferroelectricity of hafnium oxide-based materials can be precisely and selectively defined, so that hafnium oxide-based materials can be used as ideal gate oxide materials. It can better optimize the requirements for different properties such as dielectricity and ferroelectricity in the same plane, reduce the preparation steps of ferroelectric devices, and play a role in energy conservation and material reduction.

[0024] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0026] Figure 1 is a schematic structural diagram of a ferroelectric device in the prior art;

[0027] Figure 2 is a schematic diagram of oxygen vacancy and plasma treatment of the present invention, wherein (a) is a schematic diagram of exposure to plasma, and (b) is a schematic diagram of selectively reducing or eliminating the ferroelectricity of hafnium oxide-based materials;

[0028] Figure 3 is the electrical and physical property tests of Examples 1 to 3 and Comparative Example 1 of the present invention, wherein (a) is the PUND polarization test, (b) is the current density test, and (c) is the relative dielectric constant test;

[0029] Figure 4 is the current leakage test of Examples 1 to 4 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Embodiments of the present invention will be described in detail below. The embodiments described below are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0031] It should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Further, in the description of the present invention, unless otherwise stated, the meaning of "plurality" is two or more.

[0032] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0033] In this article, the term "comprising" or "including" is an open expression, that is, it includes the content specified by the present invention, but does not exclude other aspects of the content.

[0034] As Figure 1 shown, in the prior art, when both the ferroelectric capacitor region and the gate oxide region of a ferroelectric device are prepared using hafnium oxide-based materials through deposition techniques such as atomic deposition or physical vapor deposition, ferroelectricity is generated after annealing. Taking Hf 0.5 Zr 0.5 O2 (HZO) as an example, only one deposition of HZO is required, which has the advantage of simple process steps. However, after annealing HZO, ferroelectricity will also exist in the gate oxide region of the ferroelectric device, affecting the performance of the ferroelectric device. Currently, it is usually to deposit HZO first and then anneal to form ferroelectricity, and then remove all unnecessary parts, and then regrow a new high-K gate oxide material (such as HfO2) as the gate oxide of the normal select tube FET, and then remove the HfO2 deposited on the HZO. However, this process is not only cumbersome and wasteful of materials, but also may affect the performance of the ferroelectric device. Therefore, it is necessary to improve the technical defects in the preparation of ferroelectric devices in the prior art.

[0035] In the first aspect of the embodiments of the present invention, the present invention proposes a method for regulating the ferroelectricity of hafnium oxide-based materials, including:

[0036] Injecting plasma into the region to be regulated for ferroelectricity on the hafnium oxide-based material layer, and after annealing treatment, obtaining a hafnium oxide-based material layer with regulated ferroelectricity.

[0037] During the preparation of ferroelectric devices, when depositing a hafnium oxide-based material layer, the hafnium oxide-based material will cover the entire surface of the substrate, resulting in unnecessary ferroelectricity at the gate, and there will be a problem of current leakage from the gate to the substrate. Therefore, it is necessary to reduce or eliminate the unnecessary ferroelectricity. Injecting plasma into the area of the hafnium oxide-based material layer where the ferroelectricity needs to be regulated can make the hafnium oxide-based material layer exhibit selectively designed ferroelectricity. The hafnium oxide-based material has an oxygen vacancy concentration. Injecting plasma into the area where ferroelectricity needs to be eliminated in the material, after the plasma occupies the oxygen vacancies, the oxygen vacancy concentration will be reduced, thereby reducing or eliminating the ferroelectricity of the hafnium oxide-based material. Moreover, the lower the oxygen vacancy concentration, the weaker the ferroelectricity. Subsequently, during the annealing process, in the area where plasma has been injected, the plasma recombines with the oxygen vacancies, and the ferroelectricity is thus reduced or eliminated, maintaining the dielectric property, enabling the hafnium oxide-based material to be used as an ideal gate oxide material. The schematic diagram of oxygen vacancies and plasma treatment is as shown in Figure 2 shown. Thus, the method of the present invention can effectively reduce or eliminate the ferroelectricity of the hafnium oxide-based material and simplify the preparation process of ferroelectric capacitors.

[0038] In some embodiments of the present invention, the chemical general formula of the hafnium oxide-based material is Hf 1-x M x O2, where M represents a doping element, and M is selected from at least one of Zr, Al, La, Si, Sr, Mg, Y, Gd, and 0.01 ≤ x ≤ 0.99.

[0039] By doping other chemical elements in the hafnium oxide-based material, the ferroelectric properties, dielectric properties, mechanical properties, etc. of the hafnium oxide-based material can be significantly improved.

[0040] In some embodiments of the present invention, the plasma includes oxygen plasma.

[0041] In the present invention, the oxygen plasma can occupy the oxygen vacancies of the hafnium oxide-based material, reducing the oxygen vacancy concentration, thereby reducing the ferroelectric phase. Thus, the method of the present invention can effectively reduce or eliminate the ferroelectricity of the hafnium oxide-based material.

[0042] In some embodiments of the present invention, in the step of injecting plasma into the area of the hafnium oxide-based material layer where the ferroelectricity needs to be regulated, the method of generating the plasma includes at least one of inductively coupled plasma etching technology, electron cyclotron resonance technology, and capacitively coupled plasma technology.

[0043] According to the embodiments of the present invention, the oxygen inductively coupled plasma etching technology can precisely control the injection of oxygen, thereby reducing the oxygen vacancy concentration of the hafnium oxide-based material. Thus, through this method, the ferroelectricity of the material can be precisely and selectively defined.

[0044] In some embodiments of the present invention, in the oxygen inductively coupled plasma etching technology, the control parameters are as follows: the time is 10 to 40 s, and the power is 400 to 600 W.

[0045] By controlling the time and power injected into the plasma equipment, the ferroelectricity of the hafnium oxide-based material in a specific region can be effectively adjusted, the ferroelectricity of the hafnium oxide-based material can be selectively reduced or eliminated, and even a gate dielectric with extremely low leakage can be fabricated. Thus, the method of the present invention can effectively reduce or eliminate the ferroelectricity of the hafnium oxide-based material.

[0046] As an example, the time is 10 s, 12 s, 14 s, 16 s, 18 s, 20 s, 22 s, 24 s, 26 s, 28 s, 30 s, 32 s, 34 s, 36 s, 38 s, 40 s, etc.

[0047] As an example, the power is 400 W, 450 W, 500 W, 550 W, 600 W, etc.

[0048] In some embodiments of the present invention, the step of injecting plasma into the region to be regulated in ferroelectricity on the hafnium oxide-based material layer includes:

[0049] Cover the hafnium oxide-based material layer with a patterned mask, and inject plasma into the region exposed by the mask.

[0050] In some embodiments of the present invention, it includes:

[0051] Form a coating of photoresist on the hafnium oxide-based material layer to cover the expected ferroelectric region;

[0052] Remove the coating in the region exposed by the mask, and inject plasma;

[0053] Remove the coating in the expected ferroelectric region.

[0054] According to the embodiments of the present invention, since the growth of the hafnium oxide-based material layer on the substrate is global, the hafnium oxide-based material will grow on the entire substrate. Therefore, after growth, a patterned mask needs to be used to mask the hafnium oxide-based material layer for graphic definition. First, spin-coat the photoresist on the surface of the hafnium oxide-based material layer, then put the mask plate into the lithography machine for exposure to cover the expected ferroelectric region. Expose the region exposed by the exposure mask, change the properties of the photoresist here, and then put it into the developer for development to expose it. Then, remove the photoresist in the exposed region and inject plasma. Finally, remove all the photoresist on the surface of the hafnium oxide-based material layer, so that the ferroelectricity of the material can be accurately and selectively defined. In addition, compared with the traditional method of adjusting the ferroelectricity of materials on the same plane through photolithography, etching, thin film deposition, etc., the method of the present invention has the advantages of simplicity, high efficiency, energy saving and material reduction.

[0055] In some embodiments of the present invention, the photoresist includes a positive photoresist.

[0056] In some embodiments of the present invention, the temperature of the annealing treatment is ≥ 350 °C.

[0057] In the second aspect of the embodiments of the present invention, a method for preparing a ferroelectric device is proposed, which includes the method of the first aspect, as well as thin film deposition, photolithography, etching, and photoresist removal.

[0058] Thus, the method for preparing the ferroelectric device of the present invention has the advantages of simplicity, high efficiency, energy conservation, and material reduction.

[0059] In the third aspect of the embodiments of the present invention, a ferroelectric device is proposed, which includes the ferroelectric device obtained by the preparation method of the second aspect, or includes the ferroelectric device processed by the method of the first aspect.

[0060] Thus, the ferroelectric capacitance region of the ferroelectric device of the present invention has excellent ferroelectric properties, and excellent dielectric properties in the gate oxide region and other regions.

[0061] The solutions of the present invention will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0062] Example 1:

[0063] (1) Deposit about 30 nm thick tungsten metal on the surface of the silicon oxide substrate using the sputtering method, and then perform photolithography, etching, and photoresist removal;

[0064] (2) Grow a 10 nm thick Hf 0.5 Zr 0.5 O2 layer (HZO) using atomic layer deposition as the ferroelectric layer in the ferroelectric capacitance region;

[0065] (3) Spin-coat the photoresist on the HZO layer, then place the mask plate in the lithography machine for exposure, and then put it into the developer to remove the exposed part of the photoresist, inject plasma, control the operating parameters of the plasma injection device to be a power of 400 W and a duration of 15 s, then remove all the photoresist on the surface of the HZO layer, and finally perform annealing at 550 °C to form a gate oxide layer in the gate oxide region of the select tube;

[0066] (4) Grow a 10 nm thick indium gallium zinc oxide IGZO layer using atomic layer deposition, and then perform photolithography, etching, and photoresist removal to form the channel region of the select tube;

[0067] (5) Deposit a 30-nm-thick tungsten metal using electron beam evaporation, followed by photolithography, etching, and resist stripping to form the source and drain regions of the select tube and the top electrode of the ferroelectric capacitor, obtaining the FeRAM ferroelectric device.

[0068] Example 2:

[0069] The difference between Example 2 and Example 1: The operating power of Example 2 is 300 W, and the duration is 2 s.

[0070] Example 3:

[0071] The difference between Example 3 and Example 1: The operating power of Example 3 is 400 W, and the duration is 2 s.

[0072] Example 4:

[0073] The difference between Example 4 and Example 1: The operating power of Example 4 is 400 W, and the duration is 45 s.

[0074] Example 5:

[0075] The difference between Example 5 and Example 1: The operating power of Example 5 is 600 W, and the duration is 10 s.

[0076] Example 6:

[0077] The difference between Example 6 and Example 1: The operating power of Example 6 is 400 W, and the duration is 40 s.

[0078] Comparative Example 1:

[0079] The difference between Comparative Example 1 and Example 1: Comparative Example 1 does not have step (3), i.e., no oxygen plasma implantation for the HZO layer.

[0080] Performance Test

[0081] 1. Test Content

[0082] Perform electrical and physical property tests on the ferroelectric devices of Examples 1 to 6 and Comparative Example 1, detect the PUND polarization, current density, and relative dielectric constant, and then conduct a current leakage test.

[0083] 2. Test Results

[0084] The ferroelectricity of the samples in all examples decreased to varying degrees or was even almost eliminated. Among them, Figure 3It can be seen that the oxygen plasma implantation time in Example 1 is longer than that in Examples 2 and 3, and the power in Example 3 is higher than that in Example 2. Therefore, the oxygen vacancy concentration in Example 1 is the lowest, followed by Example 3, and finally Example 2. In Comparative Example 1, since no oxygen plasma was implanted, its oxygen vacancy concentration is the highest, indicating that the lower the oxygen vacancy concentration of the hafnium oxide-based material, the weaker its ferroelectricity.

[0085] It is Figure 4 known that for samples with different oxygen plasma treatment doses, the current leakage situation is also different. Among them, the oxygen vacancy concentration in Example 1 is the lowest, and the ferroelectricity in its gate oxide region is almost eliminated. Therefore, the current leakage in Example 1 is reduced by more than 10 times, and it has excellent dielectric properties.

[0086] Thus, it shows that the method of the present invention can effectively reduce or even eliminate the ferroelectricity of the hafnium oxide-based material, making it an ideal gate oxide material and having excellent dielectric properties.

[0087] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0088] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for regulating the ferroelectricity of hafnium oxide-based materials, characterized in that, Comprising: Injecting plasma into the region of the hafnium oxide-based material layer where ferroelectricity is to be regulated, and performing annealing treatment to obtain a hafnium oxide-based material layer with regulated ferroelectricity.

2. The method according to claim 1, characterized in that, The chemical general formula of the hafnium-based material is Hf 1-x M x O2, where M represents a doping element, and M is selected from at least one of Zr, Al, La, Si, Sr, Mg, Y, and Gd, and 0.01 ≤ x ≤ 0.

99.

3. The method according to claim 1, wherein The plasma includes oxygen plasma.

4. The method according to claim 1, wherein In the step of injecting plasma into the region of the hafnium oxide-based material layer where ferroelectricity is to be regulated, the method for generating plasma includes using at least one of inductively coupled plasma etching technology, electron cyclotron resonance technology, and capacitively coupled plasma technology.

5. The method according to claim 4, characterized in that, In the inductively coupled plasma etching technology, the control parameters are: time is 10 - 40 s, and power is 400 - 600 W.

6. The method according to any one of claims 1 to 4, characterized in that, The step of injecting plasma into the region of the hafnium oxide-based material layer where ferroelectricity is to be regulated includes: Covering the hafnium oxide-based material layer with a patterned mask, and injecting plasma into the exposed area of the mask.

7. The method according to claim 6, wherein Comprising: Forming a coating of photoresist on the hafnium oxide-based material layer to cover the expected ferroelectric region; Removing the coating in the exposed area of the mask, and injecting plasma; Removing the coating in the expected ferroelectric region.

8. The method according to claim 7, characterized in that, The photoresist includes positive photoresist.

9. A method for preparing a ferroelectric device, characterized in that, Comprising the method according to any one of claims 1 to 8, as well as thin film deposition, photolithography, etching, and photoresist removal.

10. A ferroelectric device, characterized in that, Comprising a ferroelectric device obtained by the preparation method according to claim 9, or a ferroelectric device processed by the method according to any one of claims 1 to 8.

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