A multi-layer doped Al 1-x Sc x Ferroelectric thin film memory and preparation method thereof

Abstract

The invention discloses a method based on multi-layer doped Al 1‑x Sc x N ferroelectric thin film memory and its preparation method, comprising a silicon substrate layer, a TiN lower electrode layer, an Al2O3 layer with a Sc doping concentration of 12.5% ​​and a 0.875 Sc 0.125 N lower buffer layer, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer, Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 N upper buffer layer, TiN upper electrode layer; the thickness of the TiN lower electrode layer and the TiN upper electrode layer are both 30 nanometers, Al 0.875 Sc 0.125 The thickness of N buffer layer is 10 nm, and Al 0.75 Sc 0.25 The thickness of the N ferroelectric material layer is 80 nanometers. The present invention is not only conducive to the high-quality growth of the material, but also improves the pressure resistance of the device, and its stability and reliability during operation are guaranteed. The existing ferroelectric memory manufacturing process can be further simplified, the operation is safe and simple, and the production cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor storage technology, and in particular to a method for storing semiconductor memory based on multi-layer doped Al 1-x Sc x N ferroelectric thin film memory and its preparation method. Background Art

[0002] Traditional perovskite ferroelectrics are currently used in ferroelectric devices due to their mature ferroelectric properties and cycle stability, but their integration is limited, and they are not environmentally friendly. They are unstable during operation and are prone to severe ferroelectric degradation. Perovskite-based ferroelectric memories also have other typical disadvantages such as low transition temperature, limited reliability and stability, nonlinear displacement or compatibility issues with complementary metal oxide semiconductor technology (CMOS). Therefore, new ferroelectric materials with improved performance can bring substantial technological innovation. Although the dielectric constant of HfO2 (hafnium oxide)-based materials is much lower than that of traditional perovskite materials, their performance still cannot fully meet the needs of integrated circuit development, as shown by the remanent polarization strength of HfO2-based materials being about 10-40μC / cm 2 . Summary of the invention

[0003] In order to overcome the above technical problems, the present invention aims to provide a multi-layer doped Al 1-x Sc x N ferroelectric thin film memory and its preparation method, using Al with excellent ferroelectric properties 1-x Sc x N thin film is used as the ferroelectric layer in the ferroelectric memory. TiN is used as the upper and lower electrodes in the structure, which can achieve compatibility with the existing CMOS process while ensuring good storage performance of the device. 0.875 Sc 0.125 N layer and Al 0.75 Sc 0.25 The stacking of N layers is not only conducive to the high-quality growth of materials, but also improves the voltage resistance of the device, ensuring its stability and reliability during operation. It can further simplify the existing ferroelectric memory manufacturing process, making the operation safe and simple, and reducing production costs.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A multi-layer doped Al 1-x Sc x The ferroelectric thin film memory of N comprises a silicon substrate layer 1, a TiN lower electrode layer 2, an Al 0.875 Sc 0.125N lower buffer layer 3, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer 4, Al doped with Sc at a concentration of 12.5% 0.875 Sc 0.125 N upper buffer layer 5, TiN upper electrode layer 6.

[0006] The thickness of the TiN lower electrode layer 2 and the TiN upper electrode layer 6 are both 30 nanometers. 0.875 Sc 0.125 The thickness of N buffer layer is 10 nm, and Al 0.75 Sc 0.25 The thickness of the 4 layers of N ferroelectric material is 80 nanometers.

[0007] The layers are vertically distributed, where the surface areas of the silicon substrate layer 1 and the TiN lower electrode layer 2 are equal, denoted as S1; the Al 0.875 Sc 0.125 N lower buffer layer 3, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer 4, Al doped with Sc at a concentration of 12.5% 0.875 Sc 0.125 The surface areas of the N upper buffer layer 5 and the TiN upper electrode layer 6 are equal, denoted as S2, and the area ratio is S1:S2=5:4.

[0008] A multi-layer doped Al 1-x Sc x A method for preparing a ferroelectric thin film memory of N, comprising the following steps;

[0009] Step 1, magnetron sputtering a TiN bottom electrode layer 2 on a silicon substrate layer 1;

[0010] Step 2: Magnetron sputtering to grow Al on the TiN lower electrode layer 2 0.875 Sc 0.125 N lower buffer layer 3;

[0011] Step 3, in Al 0.875 Sc 0.125 Magnetron sputtering growth of Al on N lower buffer layer 3 0.75 Sc 0.25 N ferroelectric material layer 4;

[0012] Step 4: 0.75 Sc 0.25 Magnetron sputtering growth of Al on N ferroelectric material layer 4 0.875 Sc 0.125 N upper buffer layer 5;

[0013] Step 5, in Al 0.875 Sc0.125 A TiN upper electrode layer 6 is formed on the N upper buffer layer 5 .

[0014] The step (1) uses a diamond pen to cut a 4-inch 110 silicon wafer into 1*1 cm 2 The squares of different sizes are used as the substrate layer and placed in a cleaning rack. They are first cleaned with deionized water for 10-15 minutes in an ultrasonic cleaning machine to remove surface dust. Then, they are ultrasonically cleaned with acetone, ethanol, and deionized water for 10-15 minutes in sequence to remove organic impurities on the substrate surface. The cleaned silicon wafer substrate is blown dry with a nitrogen gun and fixed in a special tray for magnetron sputtering. The tray is placed in a magnetron sputtering chamber for standby use to obtain a silicon substrate layer 1.

[0015] In step (2), a pure titanium metal target material with a purity of 99.999% is used as the sputtering target material of the lower electrode layer 2 by using a reactive sputtering method. The magnetron sputtering instrument is started, and after the molecular pump speed reaches 600 Hz, the vacuum is evacuated to 8*10 -4 Pa, high-purity argon gas is introduced, and the argon gas flow rate is set to 20 sccm. After the argon gas flow rate is stable, the chamber pressure is set to 1.5 Pa. After the chamber pressure is stable, the pressure is reduced to 0.2 Pa and wait for it to stabilize. The sputtering power is set to 160 W, and it is observed that the titanium target produces a light blue glow. At this time, high-purity nitrogen gas is introduced and the nitrogen flow rate is set to 1.5 sccm. At this time, it can be observed that the titanium target produces a cherry red glow in the nitrogen atmosphere, which proves that TiN is generated by reactive sputtering. After 10 minutes of pre-sputtering, the TiN lower electrode layer 2 begins to be sputtered and grown;

[0016] After magnetron sputtering to grow the TiN lower electrode layer 2 for 5-10 minutes, the sample with the grown lower electrode layer 2 is placed in a quartz boat, and the quartz boat is placed in a horizontal tube high-temperature furnace for high-temperature post-annealing treatment. Annealing is performed in a nitrogen atmosphere at 600°C for 50-70 minutes to obtain a TiN lower electrode layer 2 with a reorganized lattice after annealing.

[0017] The step (3) adopts a dual-target sputtering method, using a pure aluminum metal target material and a pure scandium metal target material with a purity of 99.999% as the doped Al 1-x Sc x The sputtering target of the N-layer thin film is prepared by surface treatment of the sample on which the TiN lower electrode layer 2 is grown in step (1) to remove impurities. The basic operation in the magnetron process is similar to that described in step (2). The doped Al is regulated by controlling the sputtering power of the pure Sc target. 1-x Sc x The content of Sc in N, thus obtaining multilayer doped Al 1-x Sc x N layers 3-5.

[0018] The step (4) grows Al-doped 1-x Scx The sample with N layer is grown with the process described in step (2) as the TiN top electrode layer 6. After sputtering for 5-10 minutes, the TiN / Al 1-x Sc x The N / TiN structured samples were annealed in a nitrogen atmosphere in a horizontal tube high temperature furnace at 600°C for 50-70 minutes.

[0019] The step (5) obtains a silicon substrate layer 1, a TiN lower electrode layer 2, and an Al2O3 layer with a Sc doping concentration of 12.5%. 0.875 Sc 0.125 N lower buffer layer 3, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer 4, Al doped with Sc at a concentration of 12.5% 0.875 Sc 0.125 The structure of the vertical distribution of the N upper buffer layer 5 and the TiN upper electrode layer 6 is a ferroelectric thin film memory structure, in which the multi-layer doped Al 1-x Sc x The N layers 3, 4, and 5 serve as active ferroelectric thin film layers.

[0020] Beneficial effects of the present invention:

[0021] The present invention uses multi-layer doped Al 1-x Sc x N material is used as the ferroelectric layer in ferroelectric memory. Compared with the traditional perovskite-based ferroelectric capacitor memory, it has better environmental friendliness and overcomes the disadvantages of its production process that is harmful to the human body. 1-x Sc x N has better coercive electric field, residual polarization intensity and other properties, which means that under the same conditions, the memory window, switching ratio and other indicators of the present invention are better in ferroelectric storage, and the stability and reliability of the data writing and reading process during operation are guaranteed.

[0022] The multilayer doped Al 1-x Sc x The N film consists of three parts: Al 0.875 Sc 0.125 N lower buffer layer, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer and Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 N upper buffer layer. The advantages of the upper and lower buffer layers are: avoiding the 0.75 Sc 0.25The lattice distortion caused by the direct contact between the N ferroelectric layer and the TiN electrode layer has an impact on the Al 0.75 Sc 0.25 The influence of the ferroelectric properties of the N layer, in which the lower buffer layer induces the Al 0.75 Sc 0.25 The role of N in growth cannot be ignored.

[0023] In the present invention, due to Al 1-x Sc x The bandgap width of N material decreases with the increase of Sc content, so Al 0.875 Sc 0.125 The bandgap width of the N buffer layer is smaller than that of the Al 0.75 Sc 0.25 N is larger. Under the same conditions, the structure with the addition of a low-concentration Sc-doped buffer layer has a higher breakdown voltage. Compared with the existing perovskite-based or hafnium oxide-based ferroelectric capacitor memory, the present invention can show good stability and reliability under high voltage conditions.

[0024] The present invention has a simple manufacturing process, mainly uses a magnetron sputtering method to prepare the relevant structure, has strong operability, and is more environmentally friendly than perovskite-based ferroelectric memory. TiN is used as the upper and lower electrodes to induce Al 1-x Sc x The ferroelectric properties of N can not only meet the excitation of high residual polarization intensity of ferroelectric capacitor memory, but also be better compatible with existing CMOS technology and have low production cost.

[0025] The ferroelectric material Al used in the present invention 1-x Sc x N remnant polarization intensity can reach 80-110μC / cm 2 , so it has huge application potential in storage.

[0026] The present invention uses multiple layers of Al doped with different concentrations. 1-x Sc x N ferroelectric film is used to replace perovskite or HfO2 materials in traditional ferroelectric memory, which can not only improve the storage performance of ferroelectric memory, but also is environmentally friendly. It can improve the storage performance of the device while being compatible with traditional CMOS process and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is based on multi-layer doped Al 1-x Sc x Schematic diagram of the structure of N's ferroelectric thin film memory.

[0028] Figure 2 Magnetron sputtering growth of multilayer doped Al 1-x Scx N-layer process flow.

[0029] Markings in the figure: 1 is the silicon substrate layer, 2 is the TiN lower electrode layer, and 3 is the Al with a Sc doping concentration of 12.5%. 0.875 Sc 0.125 N lower buffer layer, 4 is Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer, 5 is Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 The N upper buffer layers 5 and 6 are TiN upper electrode layers. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with embodiments.

[0031] like Figure 1 , Figure 2 As shown:

[0032] Example 1

[0033] Multilayer doped Al 1-x Sc x N ferroelectric thin film memory, the thickness of the TiN lower electrode layer and the TiN lower electrode layer are both 30 nanometers, and the thickness of the doped AlScN ferroelectric layer is 100 nanometers.

[0034] Using multiple layers of Al doped with different concentrations 1-x Sc x N thin film to replace the perovskite or HfO2 material in the traditional ferroelectric memory, in which Al is doped 1-x Sc x The thickness of the N ferroelectric layer consists of three parts: Al 0.875 Sc 0.125 N lower buffer layer, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer, Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 The N upper buffer layer has thicknesses of 10 nm, 80 nm, and 10 nm, respectively.

[0035] A multi-layer doped Al 1-x Sc x A method for preparing a ferroelectric thin film memory of N, the preparation method comprising:

[0036] Step 1: Prepare the TiN lower electrode layer at room temperature by magnetron sputtering, using a pure titanium metal target with a purity of 99.999%, pre-sputtering time of 10-15 minutes, pressure setting of 0.2Pa, power of 160W, argon and nitrogen flow rates of 20sccm and 1.5sccm respectively, and sputtering time of 5 minutes.

[0037] Step 2: Anneal the sample with the TiN bottom electrode grown in a nitrogen atmosphere at 600° C. for 60 min.

[0038] Step 3: Dual-target sputtering to grow multiple layers of Al doped with different concentrations 1-x Sc x For the N ferroelectric thin film layer, pure aluminum metal target and pure scandium metal target with a purity of 99.999% were used. The sputtering pressure was set to 0.6Pa, the flow ratio of argon to nitrogen was 1:1.6, the pre-sputtering time of aluminum and scandium targets was 10min, and the sputtering power of Al target was maintained at 120W during the sputtering process, and the sputtering power of Al target was maintained at 120W. 0.875 Sc 0.125 The sputtering time of N upper and lower buffer layers is 1 min, and the sputtering power of Sc target is 60 W; Al 0.75 Sc 0.25 The sputtering time of the N ferroelectric thin film layer is 15 minutes, and the sputtering power of the Sc target is 90W.

[0039] Step 4: Prepare the TiN top electrode layer using the method described in step 1. 1-x Sc x The N / TiN structured sample was annealed under the same conditions as described in step 2.

[0040] Example 2

[0041] Multilayer doped Al 1-x Sc x N ferroelectric thin film memory, the thickness of the TiN lower electrode layer and the TiN lower electrode layer are both 50 nanometers, and the thickness of the doped AlScN ferroelectric layer is 140 nanometers. The doping concentration of Al is 12.5%. 0.875 Sc 0.125 N lower buffer layer, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer, Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 The N upper buffer layer has thicknesses of 20 nanometers, 100 nanometers, and 20 nanometers, respectively.

[0042] A multi-layer doped Al 1-x Sc x A method for preparing a ferroelectric thin film memory of N, the preparation method comprising:

[0043] Step 1: Same as in Example 1, the sputtering time is 10 min.

[0044] Step 2: The sample with the TiN bottom electrode was annealed in a nitrogen atmosphere at 600° C. for 70 min.

[0045] Step 3: Dual-target sputtering to grow multiple layers of Al doped with different concentrations 1-x Sc x For the N ferroelectric thin film layer, pure aluminum metal target and pure scandium metal target with a purity of 99.999% were used. The sputtering pressure was set to 0.6Pa, the flow ratio of argon to nitrogen was 1:1.6, the pre-sputtering time of aluminum and scandium targets was 10min, and the sputtering power of Al target was maintained at 120W during the sputtering process, and the sputtering power of Al target was maintained at 120W. 0.875 Sc 0.125 The sputtering time of N upper and lower buffer layers is 3 min, and the sputtering power of Sc target is 60 W; Al 0.75 Sc 0.25 The sputtering time of the N ferroelectric thin film layer is 20 minutes, and the sputtering power of the Sc target is 90W.

[0046] Step 4: Prepare the TiN top electrode layer using the method described in step 1. 1-x Sc x The N / TiN structured sample was annealed under the same conditions as described in step 2.

[0047] Example 3

[0048] Multilayer doped Al 1-x Sc x N ferroelectric thin film memory, the thickness of the TiN lower electrode layer and the TiN lower electrode layer are both 40 nanometers, and the thickness of the doped AlScN ferroelectric layer is 120 nanometers. The doping concentration of Al is 12.5%. 0.875 Sc 0.125 N lower buffer layer, Al doped with Sc concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer, Al doped with Sc concentration of 12.5% 0.875 Sc 0.125 The N upper buffer layer has thicknesses of 15 nanometers, 90 nanometers, and 15 nanometers.

[0049] A multi-layer doped Al 1-x Sc x A method for preparing a ferroelectric thin film memory of N, the preparation method comprising:

[0050] Step 1: The same as in Example 1, except that the sputtering time is 8 minutes.

[0051] Step 2: The sample with the TiN bottom electrode was annealed in a nitrogen atmosphere at 600° C. for 70 min.

[0052] Step 3: Dual-target sputtering to grow multiple layers of Al doped with different concentrations 1-x Sc x For the N ferroelectric thin film layer, pure aluminum metal target and pure scandium metal target with a purity of 99.999% were used. The sputtering pressure was set to 0.6Pa, the flow ratio of argon to nitrogen was 1:1.6, the pre-sputtering time of aluminum and scandium targets was 10min, and the sputtering power of Al target was maintained at 120W during the sputtering process, and the sputtering power of Al target was maintained at 120W. 0.875 Sc 0.125 The sputtering time of N upper and lower buffer layers is 2 min, and the sputtering power of Sc target is 60 W; Al 0.75 Sc 0.25 The sputtering time of the N ferroelectric thin film layer is 18 minutes, and the sputtering power of the Sc target is 90W.

[0053] Step 4: Prepare the TiN top electrode layer using the method described in step 1. 1-x Sc x The N / TiN structured sample was annealed under the same conditions as described in step 2.

[0054] (1) Alternative solution for magnetron sputtering TiN lower electrode layer in the second part of the preparation method: adopt direct sputtering method, no longer introduce nitrogen, use titanium nitride ceramic target with purity of 99.99% as the sputtering target of lower electrode layer 2, start the magnetron sputtering instrument, and evacuate to 8*10 -4 Pa. Introduce high-purity argon gas, set the argon flow rate to 20 sccm, the sputtering pressure to 0.6 Pa, and after it stabilizes, set the sputtering power to 160 W and the sputtering time to 8 min;

[0055] (2) The second part of the preparation method is to grow doped Al by magnetron sputtering 1-x Sc x Alternative 1 for N layer: Using 99.99% AlSc (aluminum scandium) ceramic target and nitrogen reactive sputtering to grow Al 1-x Sc x N layer, no more Al is grown at this time 0.875 Sc 0.125 N upper and lower buffer layers, only Al is grown 1-x Sc x N ferroelectric thin film layer, wherein the Sc doping concentration is related to the parameters of the AlSc ceramic target;

[0056] (3) The second part of the preparation method is the magnetron sputtering growth of doped Al 1-x Sc x Alternative 2 for N layer: Direct sputtering growth of Al using 99.99% AlScN (aluminum scandium nitride) ceramic target 1-x Sc xN layer, no more Al is grown at this time 0.875 Sc 0.125 N upper and lower buffer layers, only Al is grown 1-x Sc x N ferroelectric thin film layer, wherein the Sc doping concentration is related to the parameters of the AlScN ceramic target.

Claims

1. A method based on multi-layer doped Al 1-x Sc x N ferroelectric thin film memory, characterized in that, The present invention comprises a silicon substrate layer (1), a TiN lower electrode layer (2), an Al2O3 layer with a Sc doping concentration of 12.5%, and a Si substrate layer (1). 0.875 Sc 0.125 N lower buffer layer (3), Al doped with Sc at a concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer (4), Al 0.875 Sc 0.125 N upper buffer layer (5), TiN upper electrode layer (6).

2. A method based on multi-layer doped Al according to claim 1. 1-x Sc x N ferroelectric thin film memory, characterized in that, The thickness of the TiN lower electrode layer (2) and the TiN upper electrode layer (6) are both 30 nanometers. 0.875 Sc 0.125 The thickness of N buffer layer is 10 nm, and Al 0.75 Sc 0.25 The thickness of the N ferroelectric material layer (4) is 80 nanometers.

3. A method based on multi-layer doped Al according to claim 1. 1-x Sc x N ferroelectric thin film memory, characterized in that, The layers are vertically distributed, where the surface areas of the silicon substrate layer (1) and the TiN lower electrode layer (2) are equal, denoted as S1; the Al 0.875 Sc 0.125 N lower buffer layer (3), Al doped with Sc at a concentration of 25% 0.75 Sc 0.25 N ferroelectric material layer (4), Al 0.875 Sc 0.125 The surface areas of the N upper buffer layer (5) and the TiN upper electrode layer (6) are equal, denoted as S2, and the area ratio is S1:S2=5:

4.

4. A method based on multi-layer doped Al according to any one of claims 1 to 3 1-x Sc x A method for preparing a ferroelectric thin film memory of N, characterized in that: The steps include: Step 1, magnetron sputtering a TiN lower electrode layer (2) on a silicon substrate layer (1); Step 2: Magnetron sputtering to grow Al on the TiN lower electrode layer (2) 0.875 Sc 0.125 N lower buffer layer (3); Step 3, in Al 0.875 Sc 0.125 Magnetron sputtering growth of Al on the N lower buffer layer (3) 0.75 Sc 0.25 N ferroelectric material layer (4); Step 4, in Al 0.75 Sc 0.25 Magnetron sputtering growth of Al on the N ferroelectric material layer (4) 0.875 Sc 0.125 N upper buffer layer (5); Step 5, in Al 0.875 Sc 0.125 A TiN upper electrode layer (6) is prepared on the N upper buffer layer (5).

5. A method based on multi-layer doped Al according to claim 4. 1-x Sc x A method for preparing a ferroelectric thin film memory of N, characterized in that: Step 1: Use a diamond pen to cut a 4-inch 110 silicon wafer into 1*1cm 2 The silicon wafer substrate is made of square blocks of different sizes and is used as a substrate layer. The square blocks are placed in a cleaning rack and first cleaned with deionized water for 10-15 minutes in an ultrasonic cleaning machine to remove surface dust. The square blocks are then ultrasonically cleaned with acetone, ethanol, and deionized water for 10-15 minutes in sequence to remove organic impurities on the substrate surface. The cleaned silicon wafer substrate is blown dry with a nitrogen gun and fixed in a special tray for magnetron sputtering. The tray is placed in a magnetron sputtering chamber for standby use to obtain a silicon substrate layer (1).

6. A method based on multi-layer doped Al according to claim 5. 1-x Sc x A method for preparing a ferroelectric thin film memory of N, characterized in that: In step 1, a pure titanium metal target material with a purity of 99.999% is used as a sputtering target material for the lower electrode layer (2) by using a reactive sputtering method. The magnetron sputtering instrument is started, and after the molecular pump speed reaches 600 Hz, the vacuum is evacuated to 8*10 -4 Pa, high-purity argon gas is introduced, and the argon gas flow rate is set to 20 sccm. After the argon gas flow rate is stable, the chamber pressure is set to 1.5 Pa. After the chamber pressure is stable, the pressure is reduced to 0.2 Pa and waited for it to stabilize. The sputtering power is set to 160 W, and it is observed that the titanium target produces a light blue glow. At this time, high-purity nitrogen gas is introduced and the nitrogen gas flow rate is set to 1.5 sccm. At this time, it can be observed that the titanium target produces a cherry red glow in the nitrogen atmosphere, which proves that TiN is generated by reactive sputtering. After 10 minutes of pre-sputtering, the TiN lower electrode layer (2) begins to be sputtered and grown; After the TiN lower electrode layer (2) is grown by magnetron sputtering for 5-10 minutes, the sample on which the lower electrode layer (2) is grown is placed in a quartz boat, and the quartz boat is placed in a horizontal tube high-temperature furnace for high-temperature post-annealing treatment. The annealing is performed in a nitrogen atmosphere at 600° C. for 50-70 minutes, thereby obtaining a TiN lower electrode layer (2) with a reorganized lattice after annealing.

7. A method based on multi-layer doped Al according to claim 6. 1-x Sc x A method for preparing a ferroelectric thin film memory of N, characterized in that: Step 2-4 adopts a dual-target sputtering method, using pure aluminum metal target and pure scandium metal target with a purity of 99.999% as the doped Al 1-x Sc x The sputtering target of the N layer thin film is prepared by surface treatment of the sample on which the TiN lower electrode layer (2) is grown in step 1 to remove impurities. The basic operation in the magnetron process is similar to that described in step 1. The doped Al is regulated by controlling the sputtering power of the pure Sc target. 1-x Sc x The content of Sc in N, thus obtaining multilayer doped Al 1-x Sc x N layers.

8. A method based on multi-layer doped Al according to claim 7. 1-x Sc x A method for preparing a ferroelectric thin film memory of N, characterized in that: The step 5 grows the doped Al 1-x Sc x The sample with N layer is grown with the process described in step 1 as the TiN top electrode layer (6). After sputtering for 5-10 minutes, the TiN / Al 1-x Sc x The N / TiN structured samples were annealed in a nitrogen atmosphere in a horizontal tube high temperature furnace at 600°C for 50-70 minutes.

Images