Hafnium oxide-based ferroelectric film capacitor and manufacturing method thereof

Abstract

The invention provides a hafnium oxide-based ferroelectric film capacitor and a manufacturing method thereof, as shown in figure 1, the hafnium oxide-based ferroelectric film capacitor comprises a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer and a top electrode which are arranged from bottom to top; and the ferroelectric layer is made of a hafnium oxide-based ferroelectric material. Thus, through introduction of the inert electrode layer, leakage current caused by tunneling current is improved, leakage current enhanced due to generation of oxygen vacancies is reduced, a leakage current channel caused by the oxygen vacancies is inhibited, and the fatigue performance of the hafnium oxide-based ferroelectric film is improved. The hafnium oxide-based ferroelectric film can realize nano-scale film deposition, is beneficial to being applied to high-integration microelectronic devices, is compatible with a CMOS (complementary metal oxide semiconductor) process, greatly reduces the production cost, and is expected to meet the development requirements of advanced devices.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor memory and integrated circuits, and in particular to a hafnium oxide-based ferroelectric film capacitor and a manufacturing method thereof. Background Art

[0002] With the rapid development of emerging technologies such as artificial intelligence, big data, and the Internet of Things, higher performance requirements are being placed on non-volatile memory. Existing Flash memory has a huge gap in read and write speed compared to DRAM, which limits the operating speed of computers. HfO2-based ferroelectric memory, as a new type of memory with great potential, has attracted widespread attention in recent years. It has many significant advantages, but also faces some challenges that need to be addressed. The fatigue performance of hafnium oxide-based ferroelectric films has always been a major problem affecting their commercial application. As the number of electric field cycles increases, oxygen vacancies are generated at the interface between the ferroelectric layer and the electrode. Oxygen vacancies are also generated in the grains within the ferroelectric layer under the action of the electric field. These oxygen vacancies form leakage current channels within the film, resulting in increased film leakage current and ultimately breakdown. Summary of the Invention (1) Purpose of the invention

[0003] In light of this, the main purpose of the present invention is to improve the leakage current caused by tunneling current and reduce the leakage current enhanced by the generation of oxygen vacancies in hafnium oxide-based ferroelectric films by introducing an inert electrode layer. This suppresses the leakage current channel caused by oxygen vacancies and further improves the fatigue performance of the hafnium oxide-based ferroelectric film. The present invention has a simple process and is compatible with CMOS technology, which is expected to meet the needs of advanced device development. (2) Technical solution

[0004] In one aspect of the present invention, a method for improving the fatigue performance of HZO ferroelectric thin films comprises: arranging from bottom to top: a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode; the material of the ferroelectric layer is a hafnium oxide-based ferroelectric material.

[0005] Preferably, the hafnium oxide-based ferroelectric material is hafnium dioxide or doped hafnium dioxide; wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen.

[0006] Preferably, the top and bottom electrodes are any one of silicide metal electrodes, nitride metal electrodes, and tungsten.

[0007] Preferably, the inert electrode layer is made of a metal or compound material with low reactivity and good electrical conductivity, such as platinum, gold, silver, etc.

[0008] Preferably, the thickness of the ferroelectric layer is 1-5 nm, and the thickness of the inert electrode layer is 0.5-1 nm.

[0009] Preferably, the thickness of the top and bottom electrodes is 40-100 nm.

[0010] A second aspect of the present invention provides a method for preparing a hafnium oxide-based ferroelectric thin film.

[0011] The method comprises: growing a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode on a substrate from bottom to top, and finally performing heat treatment to obtain a hafnium oxide-based ferroelectric thin film, wherein the top and bottom electrodes and the inert electrode layer are prepared by magnetron sputtering, and the ferroelectric layer is prepared by atomic layer deposition. Preferably, the method specifically includes:

[0012] Step 1: Place the substrate material into the magnetron sputtering chamber, wherein the substrate is n-type heavily doped silicon; evacuate to a vacuum degree of 10-10-10-6 Torr, and then deposit the bottom electrode; after completion, inflate to atmospheric pressure, open the chamber, and take out the first sample;

[0013] Step 2: Close the chamber and evacuate it to a vacuum level between 0.01-0.5 Torr, waiting for all temperature parameters to reach preset values; set the atomic layer deposition recipe and grow the ferroelectric layer; after completion, inflate to atmospheric pressure, open the chamber, and remove the second sample;

[0014] Step 3: Place the second sample in a magnetron sputtering chamber, evacuate to a vacuum degree of 10-10-10-6 Torr, and then deposit an inert electrode layer; after completion, inflate to atmospheric pressure, open the chamber, and take out the third sample;

[0015] Step 4: placing the third sample into an atomic layer deposition chamber, evacuating the chamber to a vacuum level between 0.01 and 0.5 Torr, and waiting for various temperature parameters to reach preset values; setting an atomic layer deposition recipe and growing a ferroelectric layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and removing the fourth sample;

[0016] Step 5: placing the fourth sample in a magnetron sputtering chamber, evacuating the chamber to a vacuum degree of 10-10-10-6 Torr, and then depositing an inert electrode layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and taking out the fourth sample;

[0017] Step 6: placing the fifth sample into an atomic layer deposition chamber, evacuating the chamber to a vacuum level between 0.01 and 0.5 Torr, and waiting for various temperature parameters to reach preset values; setting an atomic layer deposition recipe and growing a ferroelectric layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and removing the sixth sample;

[0018] Step 7: placing the sixth sample in a magnetron sputtering chamber, evacuating the chamber to a vacuum degree of 10-10-10-6 Torr, and then depositing an inert electrode layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and taking out the seventh sample;

[0019] Step 8: Placing the seventh sample in a rapid annealing furnace for rapid thermal annealing, wherein the annealing temperature is between 450-750°C, the annealing time is between 30-60 seconds, and the vacuum degree is between 0.01-0.2 hPa, so as to rapidly crystallize the thin film and obtain a hafnium oxide-based ferroelectric thin film. (3) Beneficial effects

[0020] The above technical solution of the present invention has the following beneficial technical effects: The present invention provides a method for preparing a hafnium oxide-based ferroelectric thin film, comprising: arranging from bottom to top: a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode; the material of the ferroelectric layer is a hafnium oxide-based ferroelectric material. Thus, if Figure 2 As shown, by introducing the inert electrode layer, the leakage current caused by tunneling current is increased, and the leakage current enhanced by the generation of oxygen vacancies is reduced, thereby suppressing the leakage current channel caused by oxygen vacancies and improving the fatigue performance of the hafnium oxide-based ferroelectric film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a hafnium oxide-based ferroelectric thin film provided in one embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a tunneling current caused by an inert electrode provided in one embodiment of the present invention; DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0024] See also Figure 1 The present invention provides a hafnium oxide-based ferroelectric thin film, comprising, arranged from bottom to top, a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode; the ferroelectric layer is made of a hafnium oxide-based ferroelectric material. Thus, by introducing the inert electrode layer, the leakage current caused by tunneling current is reduced. Figure 2, reducing the leakage current enhanced by the generation of oxygen vacancies, thereby suppressing the leakage current channel caused by oxygen vacancies, and further improving the fatigue performance of hafnium oxide-based ferroelectric films. The present invention has a simple process and is compatible with existing CMOS processes, which is conducive to commercial application.

[0025] In one embodiment, the hafnium oxide-based ferroelectric material is hafnium dioxide or doped hafnium dioxide; wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen.

[0026] In one embodiment, the top and bottom electrodes are any one of silicide metal electrodes, nitride metal electrodes, and tungsten.

[0027] In one embodiment, the inert electrode layer is made of a metal or compound material such as platinum, gold, or silver that has low reactivity and good electrical conductivity.

[0028] In one embodiment, the ferroelectric layer has a thickness of 1 to 5 nm, and the inert electrode layer has a thickness of 0.5 to 1 nm.

[0029] In one embodiment, the thickness of the top and bottom electrodes is 40-100 nm.

[0030] A second aspect of the present invention provides a method for preparing a hafnium oxide-based ferroelectric thin film, the method comprising: growing a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode on a substrate from bottom to top, and finally performing heat treatment to obtain a hafnium oxide-based ferroelectric thin film, wherein the top and bottom electrodes and the inert electrode layer are prepared by magnetron sputtering, and the ferroelectric layer is prepared by atomic layer deposition.

[0031] Step 1: Place the substrate material in a magnetron sputtering chamber, evacuate to a vacuum degree of 10-10-10-6 Torr, and then deposit the bottom electrode; after completion, inflate to atmospheric pressure, open the chamber, and take out the first sample;

[0032] Specifically, the sample is placed in a magnetron sputtering chamber, evacuated to a vacuum of 10-10-10-6 Torr, and then the top electrode is deposited (the top electrode is any one of a silicide metal electrode, a nitride metal electrode, or tungsten (W)). The corresponding target material is selected according to the material of the bottom electrode, and the deposition time is adjusted according to the thickness of the bottom electrode. After the magnetron sputtering deposition is completed, the air is inflated to atmospheric pressure, the chamber is opened, and the sample is taken out.

[0033] Step 2: Set the temperature parameters for ALD deposition (tray temperature: 220-280°C; chamber top heating plate temperature: 120-180; chamber temperature: 120-180°C; purge temperature 100-150°C; source bottle heating temperature: 100-150°C; hot trap temperature: 350-500°C; pipeline temperature: 100-150°C). Open the chamber, place the first sample and wait for deposition. Close the chamber, evacuate to a vacuum degree between 0.01-0.5 Torr, and wait for the temperature parameters to reach the preset values; set the atomic layer deposition recipe and grow the ferroelectric layer; after completion, inflate to atmospheric pressure, open the chamber, and take out the second sample;

[0034] Specifically, close the chamber, evacuate to a vacuum degree between 0.01-0.5 Torr, and wait for various temperature parameters to reach the preset values. Set the ALD deposition recipe and grow the ferroelectric layer. The ferroelectric layer is hafnium dioxide (HfO2) or doped hafnium dioxide (wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen). For hafnium, the pulse time is 0.01-0.5s and the purge time is 10-40s; the pulse time of oxygen is 0.01-0.3s and the purge time is 10-40s; the pulse time and purge time of the doping element depend on the different doping elements; the cycle period depends on the thickness of the ferroelectric layer to be grown. After the ALD deposition is completed, inflate to atmospheric pressure, open the chamber, and take out the sample.

[0035] Step 3: Place the second sample in a magnetron sputtering chamber, evacuate to a vacuum degree of 10-10-10-6 Torr, and then deposit an inert electrode layer; after completion, inflate to atmospheric pressure, open the chamber, and take out the third sample;

[0036] Specifically, the sample is placed in a magnetron sputtering chamber, evacuated to a vacuum degree of 10-10-10-6 Torr, and then the inert electrode layer is deposited. The material of the inert electrode layer is platinum (Pt), gold (Au), silver (Ag), or other metal or compound materials with low reactivity and good conductivity. The corresponding target material is selected according to the material of the inert electrode layer, and the deposition time is adjusted according to the thickness of the inert electrode layer. After the magnetron sputtering deposition is completed, it is inflated to atmospheric pressure, the chamber is opened, and the sample is taken out.

[0037] Step 4: Set the various temperature parameters for ALD deposition (tray temperature: 220-280°C; chamber top heating plate temperature: 120-180; chamber temperature: 120-180°C; purge temperature: 100-150°C; source bottle heating temperature: 100-150°C; hot trap temperature: 350-500°C; pipeline temperature: 100-150°C). Open the chamber, place the third sample into the ALD chamber, evacuate to a vacuum of between 0.01-0.5 Torr, and wait for the various temperature parameters to reach the preset values; set the ALD recipe and grow the ferroelectric layer; upon completion, inflate to atmospheric pressure, open the chamber, and remove the fourth sample.

[0038] Specifically, the fourth sample is placed in the ALD chamber, evacuated to a vacuum degree between 0.01-0.5Torr, and the temperature parameters are waited for to reach the preset value. The ALD deposition formula is set to grow the ferroelectric layer. The ferroelectric layer is hafnium dioxide (HfO2) or doped hafnium dioxide (wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen). For hafnium, the pulse time is 0.01-0.5s, and the purge time is 10-40s; the pulse time of oxygen is 0.01-0.3s, and the purge time is 10-40s; the pulse time and purge time of the doping element are determined according to the different doping elements; the cycle period depends on the thickness of the ferroelectric layer to be grown. After the ALD deposition is completed, the air is inflated to atmospheric pressure, the chamber is opened, and the sample is taken out.

[0039] Step 5: placing the fourth sample in a magnetron sputtering chamber, evacuating the chamber to a vacuum degree of 10-10-10-6 Torr, and then depositing an inert electrode layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and taking out the fifth sample;

[0040] Specifically, the sample is placed in a magnetron sputtering chamber, evacuated to a vacuum degree of 10-10-10-6 Torr, and then the inert electrode layer is deposited. The material of the inert electrode layer is platinum (Pt), gold (Au), silver (Ag), or other metal or compound materials with low reactivity and good conductivity. The corresponding target material is selected according to the material of the inert electrode layer, and the deposition time is adjusted according to the thickness of the inert electrode layer. After the magnetron sputtering deposition is completed, it is inflated to atmospheric pressure, the chamber is opened, and the sample is taken out.

[0041] Step 6: Set the various temperature parameters for ALD deposition (tray temperature: 220-280°C; chamber top heating plate temperature: 120-180; chamber temperature: 120-180°C; purge temperature: 100-150°C; source bottle heating temperature: 100-150°C; hot trap temperature: 350-500°C; pipeline temperature: 100-150°C). Open the chamber, place the fifth sample into the atomic layer deposition chamber, evacuate to a vacuum level between 0.01-0.5 Torr, and wait for the various temperature parameters to reach the preset values; set the atomic layer deposition recipe and grow the ferroelectric layer; upon completion, inflate to atmospheric pressure, open the chamber, and remove the sixth sample.

[0042] Specifically, the fifth sample is placed in an ALD chamber, evacuated to a vacuum degree between 0.01-0.5 Torr, and the temperature parameters are waited for to reach the preset values. The ALD deposition recipe is set to grow a ferroelectric layer. The ferroelectric layer is hafnium dioxide (HfO2) or doped hafnium dioxide (wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen). For hafnium, the pulse time is 0.01-0.5s and the purge time is 10-40s; the pulse time of oxygen is 0.01-0.3s and the purge time is 10-40s; the pulse time and purge time of the doping element are determined according to the different doping elements; the cycle period depends on the thickness of the ferroelectric layer to be grown.

[0043] Step 7: Place the sixth sample in a magnetron sputtering chamber, evacuate to a vacuum degree of 10-10-10-6 Torr, and then deposit the top electrode; after completion, inflate to atmospheric pressure, open the chamber, and take out the seventh sample;

[0044] Specifically, the sample is placed in a magnetron sputtering chamber and evacuated to a vacuum of 10-10-10-6 Torr. The top electrode is then deposited (the top electrode can be any of a silicide metal electrode, a nitride metal electrode, or tungsten (W)). The corresponding target material is selected based on the top electrode material, and the deposition time is adjusted based on the thickness of the top electrode. After the magnetron sputtering deposition is completed, the chamber is inflated to atmospheric pressure, the chamber is opened, and the sample is removed.

[0045] Step eight: placing the seventh sample in a rapid annealing furnace for rapid thermal annealing, wherein the annealing temperature is between 450-750° C., the annealing time is between 30-60 s, and the vacuum degree is between 0.01-0.2 hPa, so that the film is rapidly crystallized to obtain a hafnium oxide-based ferroelectric thin film.

[0046] Specifically, the annealing atmosphere is selected according to different films, and can be nitrogen or oxygen.

[0047] The present invention provides a method for preparing a hafnium oxide-based ferroelectric thin film, such as Figure 1 As shown, it includes the following components arranged from bottom to top: bottom electrode, ferroelectric layer, inert electrode layer, ferroelectric layer, inert electrode layer, ferroelectric layer, top electrode; the material of the ferroelectric layer is hafnium oxide-based ferroelectric material. Figure 2 As shown, by introducing the inert electrode layer, the leakage current caused by the tunneling current is increased, and the leakage current enhanced by the generation of oxygen vacancies is reduced, thereby suppressing the leakage current channel caused by oxygen vacancies, and further improving the fatigue performance of the hafnium oxide-based ferroelectric film. It should be understood that the above-mentioned specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the scope of protection of the present invention. In addition, the claims attached to the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims, or the equivalent forms of such scope and boundaries.

Claims

1. The present invention provides a method for improving fatigue performance of HZO ferroelectric thin films, comprising: Arranged from bottom to top: bottom electrode, ferroelectric layer, inert electrode layer, ferroelectric layer, inert electrode layer, ferroelectric layer, top electrode; The material of the ferroelectric layer is hafnium oxide-based ferroelectric material.

2. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The hafnium oxide-based ferroelectric material is hafnium dioxide or doped hafnium dioxide; wherein the doping element is a combination of one or more of silicon, aluminum, zirconium, lanthanum, cerium, yttrium, strontium, lutetium, gadolinium, scandium, neodymium, germanium, and nitrogen.

3. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The top electrode is any one of a silicide metal electrode, a nitride metal electrode, and an oxide electrode.

4. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The inert electrode layer is made of metal or compound materials such as platinum, gold, silver, etc., which have low reactivity and good electrical conductivity.

5. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The thickness of the ferroelectric layer is 1-5 nm, and the thickness of the inert electrode layer is 0.5-1 nm.

6. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The thickness of the top electrode is 40-100 nm.

7. The hafnium oxide-based ferroelectric thin film capacitor according to claim 1, wherein: The first barrier layer and the second barrier layer are made of the same material, have the same thickness and the same doping ratio.

8. A method for manufacturing a hafnium oxide-based ferroelectric thin film capacitor, characterized in that: The method comprises: growing a bottom electrode, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, an inert electrode layer, a ferroelectric layer, and a top electrode on a substrate from bottom to top, and finally performing heat treatment to obtain a hafnium oxide-based ferroelectric thin film, wherein the top and bottom electrodes and the inert electrode layer are prepared by magnetron sputtering, and the ferroelectric layer is prepared by atomic layer deposition.

9. The method for manufacturing a hafnium oxide-based ferroelectric thin film capacitor according to claim 8, wherein: The method specifically includes: Step 1: Place the substrate material into the magnetron sputtering chamber, wherein the substrate is n-type heavily doped silicon; evacuate to a vacuum degree of 10 -10 -10 -6 Torr, and then deposit the bottom electrode; after completion, fill the chamber to atmospheric pressure, open the chamber, and take out the first sample; Step 2: Close the chamber and evacuate it to a vacuum level between 0.01-0.5 Torr, waiting for all temperature parameters to reach preset values; set the atomic layer deposition recipe and grow the ferroelectric layer; after completion, inflate to atmospheric pressure, open the chamber, and remove the second sample; Step 3: Place the second sample in the magnetron sputtering chamber and evacuate to a vacuum degree of 10 -10 -10 -6 Torr, and then the inert electrode layer is deposited; after completion, the pressure is filled to atmospheric pressure, the chamber is opened, and the third sample is taken out; Step 4: placing the third sample into an atomic layer deposition chamber, evacuating the chamber to a vacuum level between 0.01 and 0.5 Torr, and waiting for various temperature parameters to reach preset values; setting an atomic layer deposition recipe and growing a ferroelectric layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and removing the fourth sample; Step 5: Place the fourth sample in the magnetron sputtering chamber and evacuate to a vacuum degree of 10 -10 -10 -6 Torr, and then the inert electrode layer is deposited; after completion, the pressure is filled to atmospheric pressure, the chamber is opened, and the fourth sample is taken out; Step 6: placing the fifth sample into an atomic layer deposition chamber, evacuating the chamber to a vacuum level between 0.01 and 0.5 Torr, and waiting for various temperature parameters to reach preset values; setting an atomic layer deposition recipe and growing a ferroelectric layer; after completion, inflating the chamber to atmospheric pressure, opening the chamber, and removing the sixth sample; Step 7: Place the sixth sample in the magnetron sputtering chamber and evacuate to a vacuum degree of 10 -10 -10 -6 Torr, and then the inert electrode layer is deposited; after completion, the pressure is filled to atmospheric pressure, the chamber is opened, and the seventh sample is taken out; Step eight: placing the seventh sample in a rapid annealing furnace for rapid thermal annealing, wherein the annealing temperature is between 450-750° C., the annealing time is between 30-60 s, and the vacuum degree is between 0.01-0.2 hPa, so that the film is rapidly crystallized to obtain a hafnium oxide-based ferroelectric thin film.

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