Method for improving durability of hafnium-based ferroelectric device and hafnium-based ferroelectric device
By preparing and controlling hafnium-based antiferroelectric films and applying electric field cycles, the problem of insufficient durability of hafnium-based ferroelectric devices is solved, and durability is achieved higher than 1012 cycles, meeting the needs of high-durability memory devices in the future.
Patent Information
- Application Number
- CN202211021475.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-24
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2042-08-24
AI Technical Summary
The existing hafnium-based ferroelectric memory devices are insufficient to meet the high durability requirements of general-purpose storage or computing devices that exceed SRAM and DRAM in the future.
By preparing a hafnium-based film on the substrate and forming a metal electrode thereon, thermal annealing makes its crystallization have antiferroelectric properties, and then applying an electric field cycle to the hafnium-based antiferroelectric film to improve its durability.
While obtaining the residual polarization strength, the hafnium-based antiferroelectric film has achieved durability of more than 1012 cycles, which significantly improves the durability of hafnium-based ferroelectric devices.
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Figure CN115332443B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of integrated circuit devices, and in particular, to a method for improving the durability of hafnium-based ferroelectric devices and hafnium-based ferroelectric devices. Background Art
[0002] In the big data era driven by artificial intelligence and Internet of Things technologies, the explosive growth of data volume poses higher requirements for the computing and storage capabilities of integrated circuits. The traditional storage technology consists of a three-level structure of static random access memory (SRAM), dynamic random access memory (DRAM), and flash memory (FLASH) to complement and balance various performances. This storage architecture has gradually become difficult to meet the storage of massive data in the big data era and the execution of high-speed and high-bandwidth memory access tasks such as deep learning. Therefore, there is an urgent need for new non-volatile storage devices with new materials, new principles, and new architectures to achieve higher speed, lower power consumption, higher density, and new functions such as in-memory computing.
[0003] Currently, several new storage technology routes have been proposed in the academic and industrial fields, including resistive random access memory (RRAM), phase change random access memory (PCRAM), spin-transfer torque magnetic random access memory (STT-MRAM), and various ferroelectric storage devices. Ferroelectric storage devices, including ferroelectric transistors (FeFETs), ferroelectric random access memories (FeRAMs), and ferroelectric tunnel junctions (FTJs), have multiple advantages such as large storage density, fast read / write speed, and low storage energy consumption. The early development of such devices was mainly based on perovskite structures such as ferroelectric materials like PZT and BTO. However, traditional perovskite ferroelectric materials have problems such as incompatibility with CMOS processes, poor scaling performance, and environmental pollution, and pose challenges in the production of processes below 130 nm. In 2011, NamLab in Germany discovered the ferroelectric properties of the high-k material hafnium oxide (HfO2) that has been maturely applied in CMOS technology. Different from traditional PZT and BTO ferroelectric materials, hafnium-based ferroelectric thin films are not only compatible with CMOS processes but also exhibit ferroelectric properties at the nanoscale (<30 nm) and have excellent scaling characteristics. Therefore, this new material can almost perfectly solve all the bottleneck problems of traditional perovskite ferroelectric materials and is expected to lead the development of new ferroelectric storage devices. Semiconductor industry observers point out that the development trend of a new generation of ferroelectric storage devices is emerging, which will change the next-generation storage pattern.
[0004] However, for the application requirements of future general-purpose storage (such as embedded storage) or in-memory computing devices that exceed SRAM and DRAM with a durability > 10 16 there are still obvious gaps in the performance of power consumption and durability. Summary of the Invention
[0005] Aiming at the problem of poor durability of existing hafnium-based ferroelectric memories and ferroelectric transistors, the purpose of the present invention is to provide a method for improving the durability of hafnium-based ferroelectric devices and hafnium-based ferroelectric devices.
[0006] According to one aspect of the present invention, a method for improving the durability of hafnium-based ferroelectric devices is provided, and the method includes:
[0007] Preparing a hafnium-based thin film on a substrate;
[0008] Forming a metal electrode on the hafnium-based thin film to form a hafnium-based device;
[0009] Performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectric characteristics, obtaining a hafnium-based antiferroelectric thin film, and forming a hafnium-based ferroelectric device;
[0010] Applying an electric field cycle to the hafnium-based antiferroelectric thin film to make the hafnium-based antiferroelectric thin film improve its durability while obtaining a remanent polarization intensity.
[0011] Further, in the step of preparing the hafnium-based thin film on the substrate, among them: the preparation method of the hafnium-based thin film includes any one of atomic layer deposition, magnetron sputtering, and laser pulse deposition.
[0012] Further, in the step of preparing the hafnium-based thin film on the substrate, among them: the thickness of the hafnium-based thin film is 0.1 - 100 nm.
[0013] Further, in the step of preparing the hafnium-based thin film on the substrate, among them: the basic material of the hafnium-based thin film is hafnium oxide, and the doping element is any one of Zr, Si, Ge, Al, Y, La, and N. According to the atomic weight ratio of the doping element to the hafnium element, the doping concentration range is 0 - 100%.
[0014] Further, in the step of forming a metal electrode on the hafnium-based thin film to form a hafnium-based device, among them: the hafnium-based device is any one of a capacitor, a transistor, and a tunnel junction.
[0015] Further, in the step of performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectricity and obtain a hafnium-based antiferroelectric thin film to form a hafnium-based antiferroelectric device, among them: the temperature of the thermal annealing is 300 - 1300 degrees.
[0016] Further, in the step of preparing the hafnium-based thin film on the substrate, among them: the substrate is formed of a metal material or a semiconductor material.
[0017] Further, the semiconductor material is any one of Si, Ge, SiC, and thin film semiconductors, and the metal material is any one of TiN, TaN, and W.
[0018] Further, applying an electric field cycle to the hafnium-based antiferroelectric thin film includes: applying a direct current (DC) electric field or an alternating current (AC) electric field cycle. The voltage amplitude of the DC electric field is 0.5 V - 20 V, and the time is 1 ps - 100 h. The voltage amplitude of the AC electric field is 0.5 V - 20 V, the cycle frequency is 1 Hz - 100 MHz, the waveform includes any one of a triangular wave, a sine wave, and a square wave, and the time is 1 ps - 100 h.
[0019] According to a second aspect of the present invention, there is provided a hafnium-based ferroelectric device, which is prepared by using the method for improving the durability of a hafnium-based ferroelectric device as described above.
[0020] Compared with the prior art, the present invention has at least one of the following beneficial effects:
[0021] By preparing a hafnium-based antiferroelectric thin film and applying an electric field cycle to the hafnium-based antiferroelectric thin film, the hafnium-based antiferroelectric thin film can obtain a remanent polarization intensity, and the hafnium-based antiferroelectric thin film can obtain a durability of more than 10 12 cycles under the condition of having a remanent polarization intensity. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] By reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent:
[0023] Figure 1 is a schematic flow chart of a method for improving the durability of a hafnium-based ferroelectric device according to an embodiment of the present invention;
[0024] Figure 2 is a schematic principle diagram of a method for improving the durability of a hafnium-based ferroelectric device according to an embodiment of the present invention;
[0025] Figure 3 is a schematic effect diagram of a method for improving the durability of a hafnium-based ferroelectric device according to an embodiment of the present invention.
[0026] In the figure: 1 is a substrate, 2 is a first TiN metal thin film, 3 is a hafnium-based thin film, 4 is a photoresist, and 5 is a second TiN metal thin film. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention. In the description of the embodiments of the present invention, it should be noted that the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here.
[0028] An embodiment of the present invention provides a method for improving the durability of a hafnium-based ferroelectric device. Referring to Figure 1 , the method includes:
[0029] Step 1, preparing a hafnium-based thin film on a substrate;
[0030] Step 2, forming a metal electrode on the hafnium-based thin film to form a hafnium-based device;
[0031] Step 3, performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectric properties, obtaining a hafnium-based antiferroelectric thin film, and forming a hafnium-based ferroelectric device;
[0032] Step 4, applying an electric field cycle to the hafnium-based antiferroelectric thin film to make the hafnium-based antiferroelectric thin film improve its durability while obtaining a remanent polarization intensity.
[0033] The principle of improving the durability of the hafnium-based ferroelectric device is as Figure 2 shown. The hafnium-based antiferroelectric material (i.e., the hafnium-based antiferroelectric thin film) formed by performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectric properties has good durability, but has no remanent polarization intensity. The ferroelectric material has good remanent polarization intensity but insufficient durability. By applying an electric field cycle to the hafnium-based antiferroelectric thin film, it can be transformed into ferroelectric properties, obtain a remanent polarization intensity, and maintain high durability at the same time.
[0034] In some specific embodiments, a hafnium-based thin film is prepared on a substrate, where: the substrate is formed of a metal material or a semiconductor material. Preferably, the semiconductor material is any one of Si, Ge, SiC, and thin film semiconductors. The metal material is any one of TiN, TaN, and W.
[0035] In some specific embodiments, a hafnium-based thin film is prepared on a substrate, where: the preparation method of the hafnium-based thin film includes any one of atomic layer deposition, magnetron sputtering, and laser pulse deposition. The thickness of the hafnium-based thin film is related to the film deposition rate and can be given according to actual needs. Preferably, the thickness of the hafnium-based thin film is 0.1 - 100 nm, and a 0.1 - 100 nm thin film can promote the formation of the hafnium-based antiferroelectric characteristics.
[0036] In some specific embodiments, a hafnium-based thin film is prepared on a substrate, where: the basic material of the hafnium-based thin film is hafnium oxide that can exhibit polarization properties and is compatible with the CMOS process, and the doping element is any one of Zr, Si, Ge, Al, Y, La, and N. Doping these elements can promote the formation of antiferroelectric characteristics in the hafnium-based thin film; according to the atomic weight ratio of the doping element to the hafnium element, the doping concentration range of the doping element is 0% to 100%, which can be given according to actual needs.
[0037] In some specific embodiments, a metal electrode is formed on the hafnium-based thin film to form a hafnium-based device, where: the hafnium-based device is any one of a capacitor, a transistor, and a tunnel junction; the material of the electrode on the top of the hafnium-based thin film includes any one of TiN, Au, Ag, Al, TaN, and RuO 2 etc. Any of these electrode materials is beneficial to the formation of the antiferroelectric characteristics of the hafnium-based thin film.
[0038] In some specific embodiments, the hafnium-based thin film is thermally annealed to make it crystallize with antiferroelectric characteristics, and various parameters are adjusted to form a hafnium-based antiferroelectric crystal structure mainly composed of a tetragonal phase, obtaining a hafnium-based antiferroelectric thin film and forming a hafnium-based antiferroelectric device, where: the annealing temperature is given according to parameters such as the type of doping element, doping concentration, upper and lower electrodes, and film thickness. Preferably, the temperature of the thermal annealing is 300 - 1300 degrees.
[0039] In some specific embodiments, an electric field cycle is applied to the hafnium-based antiferroelectric thin film, where: the electric field amplitude, mode, application time, frequency, and waveform are given according to actual needs. Preferably, applying an electric field cycle to the hafnium-based thin film includes: applying a direct current (DC) electric field or an alternating current (AC) electric field cycle. Among them, the voltage amplitude of the DC electric field is 0.5 V - 20 V, and the time is 1 ps - 100 h; the voltage amplitude of the AC electric field is 0.5 V - 20 V, the cycle frequency is 1 Hz - 100 MHz, the waveform includes any one of a triangular wave, a sine wave, and a square wave, and the time is 1 ps - 100 h. The electric field cycle can enable the hafnium-based antiferroelectric thin film to obtain a remanent polarization intensity.
[0040] In the embodiments of the present invention, by preparing and regulating the properties of hafnium-based antiferroelectric devices, the antiferroelectric thin film material can obtain a remanent polarization while maintaining high polarization reversal cycle durability. The regulation of the hafnium-based antiferroelectric material is achieved by regulating the initial properties and the number of cycles of the antiferroelectric characteristics. The frequency, amplitude, and period of the applied electric field cycle are given according to requirements. As Figure 3 shown, for a 6-nm Hf 0.2 Zr 0.8 O 2 antiferroelectric thin film, after 10 8 cycles of electric cycling, a remanent polarization intensity Pr of nearly 20 μC / cm 2 is obtained, and the durability can exceed 10 12 cycles, which is two orders of magnitude higher than that of the traditional hafnium-based ferroelectric thin film without antiferroelectric characteristics, such as Hf 0.5 Zr 0.5 O 2
[0041] In a specific embodiment, the method for improving the durability of hafnium-based ferroelectric devices includes: preparing a layer of hafnium-based antiferroelectric thin film on a semiconductor or metal substrate; spin-coating a photoresist on the hafnium-based antiferroelectric thin film and performing exposure for patterning; then depositing a metal thin film and performing photoresist stripping to form a metal electrode; subsequently, annealing the hafnium-based antiferroelectric thin film using a rapid annealing furnace to make it crystallize; and finally, applying a certain number of alternating electric field cycles to the hafnium-based antiferroelectric thin film using a ferroelectric analyzer. Specifically, referring to Figure 1 , the method includes:
[0042] S1, preparing a 30-nm first TiN metal thin film 2 on a semiconductor silicon substrate 1 using a magnetron sputtering process;
[0043] S2, preparing a 6-nm Hf 0.2 Zr 0.8 O 2 Zr-doped hafnium-based thin film 3 on the first TiN metal thin film 2 using an atomic layer deposition process;
[0044] S3, spin-coating a photoresist 4 on the hafnium-based thin film 3;
[0045] S4, patterning the photoresist 4 using a UV exposure technique;
[0046] S5, depositing a 30-nm second TiN metal thin film 5 on the hafnium-based thin film 3 using a magnetron sputtering process;
[0047] S6, forming a 40-μm x 40-μm metal electrode after stripping the photoresist 4 using a lift off process;
[0048] S7, performing 550°C N using a rapid annealing furnace 2 Atmospheric thermal annealing makes the hafnium-based thin film 3 form antiferroelectricity;
[0049] S8, using a ferroelectric parameter analyzer to perform 10 cycles of triangular-wave AC electric field with a frequency of 1 Hz and an amplitude of 3 V, so that the hafnium-based antiferroelectric thin film obtains a remanent polarization intensity. 10 cycles, so that the hafnium-based antiferroelectric thin film obtains a remanent polarization intensity.
[0050] The method for improving the durability of hafnium-based ferroelectric devices in the above embodiments of the present invention forms ferroelectric capacitors, transistors, tunnel junctions and other structures by preparing hafnium-based antiferroelectric thin films on semiconductor or metal substrates, and applying an AC electric field cycle to make the hafnium-based antiferroelectric thin film obtain a remanent polarization intensity, so that it satisfies the remanent polarization intensity while obtaining better durability.
[0051] The embodiment of the present invention also provides a hafnium-based ferroelectric device, which is prepared by using the above method for improving the durability of hafnium-based ferroelectric devices; since the hafnium-based antiferroelectric thin film obtains better durability while satisfying the remanent polarization intensity, the durability of the hafnium-based ferroelectric device can be effectively improved.
[0052] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be combined arbitrarily without conflict.
Claims
1. A method for improving the durability of hafnium-based ferroelectric devices, characterized in that, it includes: preparing a hafnium-based thin film on a substrate; forming a TiN electrode on the hafnium-based thin film to form a hafnium-based device; performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectric characteristics, obtaining a hafnium-based antiferroelectric thin film, and forming a hafnium-based ferroelectric device; applying an electric field cycle to the hafnium-based antiferroelectric thin film to improve the durability of the hafnium-based antiferroelectric thin film while obtaining a remanent polarization intensity; Among them, the material of the hafnium-based thin film is Hf 0.2 Zr 0.8 O 2 , an electrode at the bottom of the hafnium-based thin film is prepared on the substrate, the material of the bottom electrode is TiN, and the hafnium-based antiferroelectric thin film obtains a durability of more than 10 12 cycles under the condition of having a remanent polarization intensity.
2. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for preparing the hafnium-based thin film on the substrate, wherein: the preparation method of the hafnium-based thin film includes any one of atomic layer deposition, magnetron sputtering, and laser pulse deposition.
3. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for preparing the hafnium-based thin film on the substrate, wherein: the thickness of the hafnium-based thin film is 0.1 - 100 nm.
4. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for forming a TiN electrode on the hafnium-based thin film to form a hafnium-based device, wherein: the hafnium-based device is any one of a capacitor, a transistor, and a tunnel junction.
5. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for performing thermal annealing on the hafnium-based thin film to make it crystallize with antiferroelectric characteristics, obtaining a hafnium-based antiferroelectric thin film, and forming a hafnium-based antiferroelectric device, wherein: the temperature of the thermal annealing is 300 - 1300 degrees.
6. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for preparing the hafnium-based thin film on the substrate, wherein: the substrate is formed of a metal material or a semiconductor material.
7. The method for improving the durability of hafnium-based ferroelectric devices according to claim 6, characterized in that, the semiconductor material is any one of Si, Ge, SiC, and thin film semiconductors; the metal material is any one of TiN, TaN, and W.
8. The method for improving the durability of hafnium-based ferroelectric devices according to claim 1, characterized in that, for applying an electric field cycle to the hafnium-based antiferroelectric thin film, it includes: applying an electric field as a direct current electric field or an alternating current electric field cycle; wherein, the voltage amplitude of the direct current electric field is 0.5 - 20 V, and the time is 1 ps - 100 h; the voltage amplitude of the alternating current electric field is 0.5 V - 20 V, the cycle frequency is 1 Hz - 100 MHz, and the waveform includes any one of a triangular wave, a sine wave, and a square wave.
9. A hafnium-based ferroelectric device, characterized in that, it is prepared by using the method for improving the durability of hafnium-based ferroelectric devices according to any one of claims 1 - 8.