Method for maintaining high humidity environment performance of hafnium-zirconium oxide thin film ferroelectric capacitor

Abstract

The application discloses a high-humidity environment performance maintaining method for hafnium-zirconium oxide thin film ferroelectric capacitor, which comprises annealing treatment after a wet process and a moisture-resistant structure of the device. In the wet process, the hafnium-zirconium oxide thin film is easy to react with water vapor to generate zirconium hydroxide. The reaction can be reversed by selecting a proper annealing temperature, so that the stability of the thin film composition is ensured. Meanwhile, the hafnium-zirconium oxide thin film device is easy to absorb moisture in the environment, thereby affecting the performance. Therefore, an oxide thin film with positive Gibbs free energy in the reaction with water vapor is selected as a protective layer to inhibit the reaction of the thin film with water vapor. The application can effectively maintain the performance of the hafnium-zirconium oxide thin film ferroelectric device, and is relatively simple in process implementation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of semiconductor and integrated circuit, and particularly relates to a high-humidity environment performance maintaining method for hafnium-zirconium oxide thin film ferroelectric capacitor. BACKGROUND

[0002] Hafnium-zirconium oxide (HZO) thin films have been widely used in ferroelectric memory applications, including ferroelectric random access memory (FeRAM), ferroelectric transistors, and ferroelectric tunnel junctions, due to their excellent compatibility with standard CMOS processes and superior scaling characteristics. As semiconductor technology continues to advance, there is an increasing demand for high-performance memory devices. Hafnium-zirconium oxide thin films have become a focus of research due to their superior electrical properties and stability.

[0003] Currently, research on hafnium-zirconium oxide thin films has mainly focused on their failure mechanisms and durability characteristics. Previous studies have shown that hafnium-zirconium oxide thin films can achieve a durability of up to 10 14 Despite significant progress in the study of hafnium-zirconium oxide thin film durability, there are still some issues that need to be addressed, particularly the impact of wet processes on the reliability of hafnium-zirconium oxide thin films and specific solutions to performance changes caused by moisture absorption after device fabrication.

[0004] In wet processes, hafnium-zirconium oxide thin films are prone to react with water, forming zirconium hydroxide. This process can lead to changes in the chemical composition and structural degradation of the thin film, affecting its electrical properties and long-term stability. Although some theoretical analyses have explored the impact of wet processes on thin films, there is still a lack of specific solutions to this problem, particularly in terms of effectively preventing the negative impact of moisture on thin films during actual manufacturing processes.

[0005] In addition, after device fabrication is complete, long-term exposure to humid environments can cause moisture absorption, further leading to performance degradation. This phenomenon can cause serious problems in many application scenarios, especially in high-temperature and high-humidity working environments. To maintain the performance of hafnium-zirconium oxide thin film devices, researchers need to develop effective protection measures, such as selecting appropriate protective layer materials to prevent moisture intrusion or optimizing process parameters to reduce the moisture absorption of thin films.

[0006] In summary, although hafnium-zirconium oxide thin films have made important progress in terms of performance and durability, the impact of wet processes and environmental humidity on their performance remains a key issue that needs to be addressed. Future research should focus on exploring more effective process improvements and protection measures to ensure the performance of hafnium-zirconium oxide thin films in practical applications. SUMMARY

[0007] The application aims at the influence of humidity on the thin film of the existing hafnium-zirconium oxide thin film device in the process preparation and actual use, and provides a high-humidity environment performance maintaining method for the hafnium-zirconium oxide thin film ferroelectric capacitor.

[0008] The application is realized by the following technical scheme: the hafnium-zirconium oxide thin film ferroelectric capacitor device after the high-humidity environment treatment is subjected to rapid thermal annealing treatment. The annealing temperature is obtained by HSC simulation calculation, the temperature is based on the Gibbs free energy change of zirconium oxide and water vapor at different temperatures, and is set to be lower than the crystallization temperature of the hafnium-zirconium oxide thin film. This method can make the zirconium hydroxide generated in the wet process decompose into zirconium oxide again, and the reaction formula is as follows:

[0009]

[0010] For the prepared ferroelectric capacitor device, a layer of oxide film which does not react with water vapor is covered as a protective layer to effectively isolate the hafnium-zirconium oxide thin film from water vapor. This measure can prevent moisture from entering and reduce the chemical reaction and performance degradation caused by moisture absorption, so as to ensure the stability of the composition and structure of the thin film.

[0011] The selected oxide film has good chemical inertness and can block the influence of moisture in various environmental conditions. By introducing this protective layer, it is ensured that the hafnium-zirconium oxide thin film is not disturbed by external water vapor during use, and the electrical properties and long-term reliability are maintained.

[0012] Further, vacuum rapid thermal annealing is adopted, and the vacuum environment can effectively protect the metal part of the thin film and the device.

[0013] Further, the oxide protective layer is silicon oxide.

[0014] Further, the hafnium-zirconium oxide thin film ferroelectric capacitor adopts a metal-insulator-metal sandwich type capacitor structure stacked by a silicon substrate, a bottom electrode, an oxide layer and a top electrode; the silicon substrate adopts heavily doped P-type silicon; the bottom electrode adopts TiN deposited by ALD; the oxide layer adopts a hafnium-zirconium oxide thin film layer with a thickness of 10 nm deposited by ALD, and the element ratio of hafnium to zirconium is 1:1; a layer of tungsten is sputtered and deposited on the hafnium-zirconium oxide thin film layer as the top electrode.

[0015] Further, in the preparation process of the hafnium-zirconium oxide thin film ferroelectric capacitor, after the deposition of the bottom electrode, the deposition of the hafnium-zirconium oxide thin film and the deposition of the top electrode, the following is performed:

[0016] Annealing process: put the TiN / HZO / W sample into a rapid thermal annealing cavity, and vacuumize the cavity to a pressure less than 5x10 -2After Pa, nitrogen gas is introduced into the cavity at a rate of 1 L / min for 1 min, the nitrogen flow is kept unchanged, and the temperature is rapidly increased to 500℃, and after 1 min of stabilization, nitrogen gas is introduced at a rate of 30 L / min to rapidly cool the sample to 100℃, and then the sample is taken out;

[0017] Top electrode removal: The sample is soaked in hydrogen peroxide for 3-5 min to remove the top metal tungsten in the annealed crystalline Si / TiN / HZO / W structure, and expose the HZO film;

[0018] Different humidity environment treatment of HZO film: randomly select one piece of Si / TiN / HZO structure with the same batch of top electrode removal and place it in a constant temperature and humidity chamber with a temperature of 80℃ and a relative humidity of 90%; select another piece and place it in a constant temperature and humidity chamber with a temperature of 80℃ and a relative humidity of 30%; respectively, the samples are subjected to 24h, 36h, 48h of moisture absorption treatment;

[0019] Rapid thermal annealing after sample moisture absorption treatment: the sample after moisture absorption treatment is placed in a rapid thermal annealing cavity, and the cavity pressure is less than 3x10 -2 After Pa, nitrogen gas is introduced into the cavity at a rate of 1 L / min for 2 min, the nitrogen flow is kept unchanged, and rapid thermal annealing is carried out at 100 / 200 / 300 / 400℃ respectively for 1 min, and then nitrogen gas is introduced at a rate of 30 L / min to rapidly cool the sample to 80℃, and then the sample is taken out;

[0020] Redeposition of top electrode and patterning.

[0021] Further, the bottom electrode deposition is specifically:

[0022] Before the bottom electrode deposition, the silicon substrate is cleaned to improve the quality of subsequent film deposition;

[0023] After cleaning, the substrate is blown dry with a nitrogen gun, and then TiN is prepared for deposition; 10nm thick TiN is deposited by ALD, titanium tetrachloride and ammonia are used as Ti and N precursor sources respectively, and nitrogen is used as carrier gas and purge gas; the deposition temperature is 400℃, the base pressure of the TiN ALD deposition cavity is 100Pa, and the deposition rate of TiN is 0.02nm / cycle.

[0024] Further, the hafnium zirconium oxide film deposition is specifically:

[0025] The hafnium and zirconium oxide film is deposited by using tetrakis(ethylmethylamino) hafnium and tetrakis(ethylmethylamino) zirconium as the precursor materials of HfO2 and ZrO2 respectively, using plasma oxygen as the reaction gas, the overall deposition process is plasma enhanced atomic layer deposition, the growth temperature is 270℃, the base pressure of the ALD deposition cavity of the HZO film is 30Pa, and the deposition rate of HfO2 and ZrO2 is 0.1nm / cycle; by adjusting the cycle order and cycle number of the HZO film deposition, one layer of HfO2 and one layer of ZrO2 are alternately deposited, and the total deposition number is 100 cycles.

[0026] Further, the top electrode deposition is specifically:

[0027] The top electrode tungsten is deposited by using the sputtering method, the hafnium zirconium oxide film deposited sample is put into the physical vapor deposition cavity, after the cavity pressure is less than 5*10 -4 Pa, argon gas is introduced to adjust the cavity pressure to about 0.5Pa, the sputtering power is adjusted, and the tungsten is deposited on the sample at a rate of 2nm / min; the thickness of the tungsten electrode is 100nm, which ensures that the HZO film provides sufficient stress during the annealing crystallization process.

[0028] Further, the top electrode patterning is specifically:

[0029] Top electrode photolithography: spin coating photoresist at a rate of 4000rpm / s, heating at a temperature of 105℃ for 1min after spin coating to evaporate the solvent in the photoresist; using a contact exposure photolithography machine, the sample is tightly attached to the mask plate with a circular array arrangement of device patterns, using near ultraviolet light to expose the unshielded area, using developing solution to dissolve the exposed part, after deionized water rinsing, using nitrogen gun to dry;

[0030] Etching: using a reaction ion etching process with good collimation, using a mixture of SF6 and O2 as the reaction gas, the radio frequency power for etching is set to 100W, the inductively coupled plasma power is 400W, and the etching time is set to 25s to ensure that the tungsten electrode is completely etched clean;

[0031] Photoresist removal and back electrode deposition: after etching, the sample is immersed in acetone and ultrasonically treated until the photoresist is completely dissolved, deionized water is used for rinsing, and nitrogen gun is used for drying; a layer of aluminum back electrode is deposited on the back of the silicon substrate by using the thermal evaporation method to form a good ohmic contact.

[0032] Further, after the ferroelectric capacitor is prepared, 300nm of silicon oxide is grown by plasma enhanced chemical vapor deposition to completely cover the device area; the sample surface after deposition of silicon oxide is polished by a chemical mechanical polishing surface planarization process to polish the silicon oxide layer to expose the top electrode of the ferroelectric capacitor; at this time, the device is protected by silicon oxide and the top tungsten electrode, which can effectively isolate the influence of water vapor.

[0033] The present application has the following advantages: first, the present application can effectively maintain the performance of hafnium-zirconium oxide thin film after wet process; second, the process steps and device structure adopted by the present application are simple and do not increase additional cost; third, the present application has good compatibility with standard CMOS process. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0035] Figure 1 Structure diagram of hafnium-zirconium oxide thin film ferroelectric capacitor device in the present application;

[0036] Figure 2 Process preparation flow chart of hafnium-zirconium oxide thin film ferroelectric capacitor device in the present application;

[0037] Figure 3 Process simulation flow of hafnium-zirconium oxide thin film high humidity environment treatment in the present application;

[0038] Figure 4 Gibbs free energy of zirconium oxide and water vapor at different temperatures in the present application;

[0039] Figure 5 Polarization strength of samples after high humidity environment treatment after annealing at different temperatures;

[0040] Figure 6 Gibbs free energy of different oxide thin films reacting with water vapor at normal temperature and pressure in the present application;

[0041] Figure 7 Structure diagram of additional oxide protective thin film in the present application and process flow. DETAILED DESCRIPTION

[0042] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0043] It should be apparent that the described embodiments are merely a few of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0044] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0045] Figure 1 A schematic diagram of a hafnium-zirconium oxide thin film ferroelectric capacitor structure of the present application. A sandwich type capacitor structure of metal-insulator-metal (MIM) is adopted, which is stacked by a silicon substrate, a bottom electrode, an oxide layer, and a top electrode. In the capacitor structure, heavily doped P-type silicon with (100) crystal orientation is selected as the substrate material, mainly considering the low resistivity (<0.001 Ω·cm) of the heavily doped P-type silicon and the ease of forming ohmic contact with metals such as aluminum, which facilitates subsequent wiring test. The bottom electrode adopts titanium nitride (TiN) deposited by atomic layer deposition (ALD), which not only provides stress for the HZO thin film during annealing, but also acts as a barrier layer to prevent impurities from diffusing into the HZO thin film. The oxide layer adopts a hafnium-zirconium oxide thin film layer with a thickness of 10 nm deposited by ALD, and the element ratio of hafnium to zirconium is 1:1; on the HZO thin film, a tungsten electrode is sputtered and deposited as the top electrode of the device, which provides stress during the subsequent annealing and crystallization process and improves the ferroelectricity of the HZO thin film.

[0046] Figure 2 A preparation process of a hafnium-zirconium oxide thin film ferroelectric capacitor, which mainly includes four parts:

[0047] (1) Bottom electrode deposition

[0048] Before the deposition of the bottom electrode, the silicon substrate is cleaned to remove residual organic matter, metal ions, etc. on the surface, thereby improving the quality of subsequent thin film deposition. The cleaning steps are as follows:

[0049] a) Acetone solution cleaning: immerse the substrate in acetone solution at room temperature, ultrasonic for 5 min, and then rinse with deionized water. Acetone can effectively remove organic matter on the surface of the substrate.

[0050] b) Diluted hydrofluoric acid (HF) solution cleaning: immerse the substrate in a 2% volume fraction of HF solution for 1 min, and then rinse with deionized water. This step is to remove the natural oxide layer on the surface of the silicon substrate.

[0051] c) SC-1 solution cleaning: The substrate after the above cleaning process is immersed in SC-1 solution (NH4OH:H2O2:H2O = 1:1:5) at 80°C for 5 min, and then rinsed with deionized water. The SC-1 solution can effectively remove solid particles and organic matter on the surface of the substrate.

[0052] d) SC-2 solution cleaning: The substrate after the above cleaning process is immersed in SC-2 solution (HCl:H2O2:H2O = 1:1:6) at 80°C for 10 min, and then rinsed with deionized water. This step is to remove ions and heavy metal particles on the surface of the silicon substrate.

[0053] After cleaning, the substrate is blown dry with a nitrogen gun, and then TiN is prepared for deposition. A 10 nm thick TiN is deposited by ALD, titanium tetrachloride (TiCl4) and ammonia gas are used as the precursor sources of Ti and N respectively, and nitrogen gas is used as the carrier gas and purge gas. The deposition temperature is about 400°C, the base pressure of the ALD deposition chamber of TiN is 100 Pa, and the deposition rate of TiN is about 0.02 nm / cycle.

[0054] (2) Hafnium zirconium oxide film deposition

[0055] After the deposition of the bottom electrode TiN, the deposition of the HZO film is carried out, and tetrakis(ethylmethylamino)hafnium and tetrakis(ethylmethylamino)zirconium are used as the precursor materials of hafnium oxide (HfO2) and zirconium oxide (ZrO2) respectively, and plasma oxygen is used as the reaction gas. The overall deposition process is plasma enhanced atomic layer deposition, the growth temperature is 270°C, the base pressure of the ALD deposition chamber of HZO film is 30 Pa, and the deposition rate of HfO2 and ZrO2 is about 0.1 nm / cycle. By adjusting the cycle order and cycle number during the deposition of the HZO film, a layer of HfO2 and a layer of ZrO2 are alternately deposited, and the total deposition number is 100 cycles.

[0056] (3) Top electrode deposition

[0057] The top electrode tungsten (W) is deposited by sputtering. After the sample deposited in step (2) is placed in a physical vapor deposition chamber, the chamber pressure is less than 5x10 -4 Pa, argon gas is introduced to adjust the chamber pressure to about 0.5 Pa, and the sputtering power is adjusted so that tungsten is deposited on the sample at a rate of 2 nm / min. The thickness of the tungsten electrode is about 100 nm, which ensures that the HZO film provides sufficient stress during the annealing crystallization process.

[0058] (4) Annealing crystallization and top electrode patterning

[0059] a) Annealing process

[0060] The TiN / HZO / W sample was placed in a rapid thermal annealing chamber, vacuumed to a chamber pressure of less than 5x10 -2 After the pressure was stabilized at 1x10 Pa, nitrogen (N2) was introduced into the chamber at a rate of 1 L / min for 1 min, the N2 flow was kept constant, the temperature was rapidly increased to 500°C, and after 1 min of stabilization, N2 was introduced at a rate of 30 L / min to rapidly cool the sample to 100°C, and then the sample was removed.

[0061] b) Top electrode photolithography

[0062] The photoresist AR-P 5350 was spin-coated at a rate of 4000 rpm / s, and after spin-coating, the sample was heated at a temperature of 105°C for 1 min to evaporate the solvent in the photoresist and improve the adhesion of the photoresist on the tungsten top electrode. Then, the sample was placed in close contact with a mask plate with a circular array pattern using a contact exposure photolithography machine, and the areas not covered by the mask plate were exposed to near-ultraviolet light. The exposed parts were dissolved using a prepared developer (AR 300-26:H2O = 1:7), and after rinsing with deionized water, the sample was blown dry with a nitrogen gun.

[0063] c) Etching

[0064] To ensure the accuracy of the device pattern, a reaction ion etching process with good collimation was used, and a mixture of SF6 and O2 was used as the reaction gas. The radio frequency power for etching was set to 100 W, the inductively coupled plasma power was 400 W, and the etching time was set to 25 s to ensure that the tungsten electrode was completely etched clean.

[0065] d) Back electrode deposition after photoresist removal

[0066] After etching, the sample was immersed in acetone and ultrasonically treated until the photoresist was completely dissolved, then rinsed with deionized water and blown dry with a nitrogen gun. A layer of aluminum back electrode was deposited on the back of the silicon substrate using thermal evaporation to form a good ohmic contact.

[0067] Figure 3 The process flow for the high humidity environment treatment of the HZO film in the present application and the subsequent rapid thermal annealing recovery process flow are as follows:

[0068] (1) Top electrode removal

[0069] The sample was soaked in hydrogen peroxide for 3-5 min to remove the top tungsten metal in the Si / TiN / HZO / W structure that had been annealed and crystallized, exposing the HZO film for subsequent high humidity environment treatment.

[0070] (2) Different humidity environment treatment of HZO film

[0071] A piece of the same batch of Si / TiN / HZO structure with the top electrode removed was randomly selected and placed in a constant temperature and humidity chamber with a temperature of 80°C and a relative humidity RH of 90%; another piece was placed in a constant temperature and dryness chamber with a temperature of 80°C and a relative humidity RH of 30%. The samples were subjected to 24h, 36h, 48h of moisture absorption treatment, respectively.

[0072] (3) Rapid thermal annealing of the samples after moisture absorption treatment

[0073] The samples after moisture absorption treatment were placed in a rapid thermal annealing cavity, and the cavity was vacuumed to a pressure less than 3x10 -2 Pa, nitrogen (N2) was introduced into the cavity at a rate of 1L / min for 2min, the N2 flow rate was kept unchanged, and the samples were rapidly thermal annealed at temperatures of 100 / 200 / 300 / 400°C for 1min, respectively, then nitrogen was introduced at a rate of 30L / min to rapidly cool the samples to 80°C, and then the samples were taken out.

[0074] (4) Resedimentation of the top electrode and patterning

[0075] The specific process flow is the same as the preparation process of the conventional ferroelectric capacitor described above.

[0076] Figure 4 The Gibbs free energy of the reaction of zirconium oxide with water vapor at different temperatures is calculated by the formula:

[0077] ΔG = ΔH - TΔS

[0078] where ΔH is the reaction enthalpy, ΔS is the reaction entropy, and T is the reaction temperature. When ΔG < 0, the energy of the system decreases after the reaction, indicating that the reaction can proceed spontaneously, and the greater the absolute value of ΔG, the faster the reaction rate. Conversely, when ΔG > 0, the reaction is non-spontaneous and tends to proceed in the reverse direction. The Gibbs free energy of the reaction of zirconium oxide with water vapor at different temperatures was calculated using HSC software. The Gibbs free energy of the reaction of zirconium oxide with water vapor is greater than zero when the temperature exceeds 260°C, at which time the reaction tends to proceed in the reverse direction, and zirconium hydroxide is more likely to decompose into zirconium oxide and water. In actual annealing treatment, temperatures exceeding 260°C are more beneficial to the recovery of device performance.

[0079] Figure 5 The polarization strength of the sample after 48h of high-humidity environment treatment at a temperature of 80°C and a relative humidity of 90% after annealing at different temperatures, where 2P r is the polarization strength of the sample. Refer to Figure 4The calculation results show that when the annealing temperature is lower than 260℃, the recovery amount of the polarization intensity is small, and there is a large gap with the sample without moisture absorption treatment. With the annealing temperature rising to 300℃, the polarization intensity is recovered to the same level as the performance of the HZO thin film without moisture absorption treatment. At 400℃, due to the annealing recovery effect, the polarization intensity is partially improved compared with the performance of the HZO thin film without moisture absorption treatment.

[0080] Figure 6 The Gibbs free energy of the reaction of the oxide thin film with water vapor at normal temperature and pressure in the application is shown in the data in the figure. The Gibbs free energy of the reaction of most high-k oxide thin films with water vapor is less than zero, and the corresponding hydroxide is easily generated by reacting with water vapor in a high-humidity environment, thereby adversely affecting the performance of the HZO thin film. Based on the calculation data, cerium oxide, silicon oxide, scandium sesquioxide and hafnium oxide are not easy to react with water vapor, and can maintain good characteristics in a high-humidity environment. Considering the compatibility of the deposition process and the device, as well as the cost and time of thin film deposition, silicon oxide is selected as the thin film isolation layer to protect the device.

[0081] Figure 7 The structure diagram and process flow of the additional oxide protective thin film in the application are shown in the figure. After the preparation of the ferroelectric capacitor device is completed, 300nm of silicon oxide is grown by plasma enhanced chemical vapor deposition to completely cover the device area. Through the surface planarization process of chemical mechanical polishing (CMP), the surface silicon oxide layer of the sample after deposition of silicon oxide is polished to expose the top electrode of the ferroelectric capacitor. At this time, the device is protected by silicon oxide and the top tungsten electrode, which can effectively isolate the influence of water vapor.

[0082] The above only describes the preferred embodiments of one or more embodiments of the present application, and does not limit one or more embodiments of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of one or more embodiments of the present application.

Claims

1. A method for maintaining high humidity environment performance of a hafnium zirconium oxide thin film ferroelectric capacitor, characterized by, The method comprises: The hafnium-zirconium oxide thin film ferroelectric capacitor device treated in a high humidity environment is subjected to rapid thermal annealing treatment; the rapid thermal annealing treatment temperature is determined according to the Gibbs free energy change of the reaction of zirconium oxide with water vapor at different temperatures; the rapid thermal annealing treatment temperature is lower than the crystallization temperature of the hafnium-zirconium oxide thin film, and is higher than the temperature at which the Gibbs free energy of the reaction of zirconium oxide with water vapor is zero, so as to realize the decomposition of zirconium hydroxide; According to the Gibbs free energy of the reaction of different oxide materials with water vapor at normal temperature and pressure, an oxide protective layer is selected; the oxide protective layer reacts with water vapor at normal temperature and pressure with a Gibbs free energy greater than zero, and cannot generate the corresponding hydroxide, thereby effectively isolating the hafnium-zirconium oxide thin film from water vapor and protecting the internal components of the hafnium-zirconium oxide thin film from the influence of external humidity.

2. The method of claim 1, wherein the method is performed in a high humidity environment. Vacuum rapid thermal annealing is adopted, and the vacuum environment can effectively protect the metal parts of the thin film and the device.

3. The method of claim 1, wherein the method is performed in a high humidity environment. The oxide protective layer is silicon oxide.

4. The method of claim 1, wherein the method is performed in a high humidity environment. The hafnium-zirconium oxide thin film ferroelectric capacitor adopts a metal-insulator-metal sandwich type capacitor structure, which is stacked by a silicon substrate, a bottom electrode, an oxide layer and a top electrode; the silicon substrate adopts heavily doped P-type silicon; the bottom electrode adopts ALD-deposited TiN; the oxide layer adopts an ALD-deposited hafnium-zirconium oxide thin film layer with a thickness of 10 nm, and the element ratio of hafnium to zirconium is 1:1; a layer of tungsten is sputtered and deposited on the hafnium-zirconium oxide thin film layer as the top electrode.

5. The method of claim 4, wherein the method is performed in a high humidity environment. The bottom electrode deposition specifically comprises: Before the bottom electrode deposition, the silicon substrate is cleaned to improve the quality of subsequent thin film deposition; After cleaning, the substrate is blown dry with a nitrogen gun, and then TiN is prepared for deposition; 10 nm thick TiN is deposited by ALD, titanium tetrachloride and ammonia gas are used as the precursor sources of Ti and N respectively, and nitrogen gas is used as the carrier gas and purging gas; the deposition temperature is 400 DEG C, the base pressure of the ALD deposition cavity of TiN is 100 Pa, and the deposition rate of TiN is 0.02 nm / cycle.

6. The method of claim 4, wherein the method is performed in a high humidity environment. The hafnium-zirconium oxide thin film deposition specifically comprises: Four (ethylmethylamino) hafnium and four (ethylmethylamino) zirconium are used as the precursor materials of HfO2 and ZrO2 respectively, and plasma oxygen is used as the reaction gas, the overall deposition process is plasma-enhanced atomic layer deposition, the growth temperature is 270 DEG C, the base pressure of the ALD deposition cavity of HZO thin film is 30 Pa, and the deposition rate of HfO2 and ZrO2 is 0.1 nm / cycle; by adjusting the cycle order and cycle number of HZO thin film deposition, one layer of HfO2 and one layer of ZrO2 are deposited alternately, and the total deposition times is 100 cycles.

7. The method of claim 4, wherein the method is performed in a high humidity environment. The top electrode deposition specifically comprises: The top electrode tungsten is deposited by sputtering. The sample on which hafnium-zirconium oxide film is deposited is put into a physical vapor deposition cavity. When the cavity pressure is less than 5*10 -4 After 30 min, argon is introduced to adjust the cavity pressure to about 0.5 Pa, and the sputtering power is adjusted so that tungsten is deposited on the sample at a rate of 2 nm / min. The thickness of the tungsten electrode is 100 nm, which ensures that sufficient stress is provided to the HZO film during the annealing and crystallization process.

8. The method of claim 4, wherein the method is performed in a high humidity environment. The top electrode patterning specifically comprises: Top electrode photolithography: spin-coat photoresist at a rate of 4000 rpm / s, heat at a temperature of 105 DEG C for 1 min after spin-coating is completed to evaporate the solvent in the photoresist; use a contact exposure photolithography machine to tightly attach the sample to a mask plate with a circular array arrangement of device patterns, use near ultraviolet light to expose the unshielded area, use developing solution to dissolve the exposed part, and then use deionized water to rinse and blow dry with a nitrogen gun. Etching: A reactive ion etching process with good collimation is used, and SF6 and O2 are used as the reaction gas. The radio frequency power for etching is set to 100 W, the inductively coupled plasma power is 400 W, and the etching time is set to 25 s to ensure that the tungsten electrode is completely etched clean; Back electrode deposition: After etching, the sample is immersed in acetone and ultrasonically treated until the photoresist is completely dissolved. Deionized water is used for rinsing, and a nitrogen gun is used for drying. A layer of aluminum back electrode is deposited on the back of the silicon substrate by thermal evaporation to form a good ohmic contact.

9. The method of claim 1, wherein the method is performed in a high humidity environment. After the ferroelectric capacitor is prepared, a 300 nm thick silicon oxide is grown by plasma-enhanced chemical vapor deposition to completely cover the device area. Through a surface planarization process of chemical mechanical polishing, the surface silicon oxide layer of the sample after deposition of silicon oxide is polished to expose the top electrode of the ferroelectric capacitor. At this time, the device is protected by silicon oxide and the top tungsten electrode, which can effectively isolate the influence of water vapor.

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