A method for preparing an AlScN thin film by atomic layer deposition

Abstract

The application provides a method for preparing an AlScN film by atomic layer deposition, which comprises the following steps: placing a substrate into a deposition chamber; after the deposition chamber is pumped to a preset pressure, heating the deposition chamber and constantly feeding a carrier gas into the deposition chamber; performing an AlN deposition cycle on the surface of the substrate a times; performing a ScN deposition cycle b times; repeating the steps of the AlN deposition cycle a times and the ScN deposition cycle b times until the film reaches a target thickness, and obtaining an Al 1‑x Sc x N film after cooling. The application fully utilizes the growth principle of surface self-limitation of the atomic layer deposition process, realizes the atomic scale accurate regulation of the film thickness, realizes the accurate regulation of the component ratio by utilizing the periodic ratio regulation of the AlN and the ScN, and realizes the integration capability of the three-dimensional structure by utilizing the uniformity of the ALD process film.

Description

Technical Field

[0001] This invention relates to the field of ferroelectric thin film technology, and more specifically, to a method for preparing AlScN thin films by atomic layer deposition. Background Technology

[0002] Ferroelectric memories (FeRAMs) are characterized by high speed, low power consumption, high data reliability, and high durability. Ferroelectric thin film materials are an important component of ferroelectric memories. Among them, 1T1C type ferroelectric RAMs (FeRAMs) based on traditional ferroelectric materials such as lead zirconate titanate (PZT) have achieved commercial production, with main applications including dashcams, IC cards, and instruments. However, ferroelectric ceramic materials such as PZT are difficult to integrate with semiconductor materials to realize ferroelectric transistor memories. Ferroelectric hafnium-based oxides based on atomic layer deposition processes, such as hafnium zirconium oxide and hafnium silicon oxide, can maintain ferroelectricity, high speed, high data retention, and high durability even at a thickness of a few nanometers, thus enabling their application in small-size ferroelectric transistor memories and attracting widespread attention from academia and industry in recent years. However, ferroelectric hafnium-based oxide devices still face challenges in terms of data retention, durability, and driving voltage.

[0003] Al x Sc1-xN is a novel ferroelectric thin film material whose polarization charge density and coercive electric field can be tunably controlled over a wide range by adjusting the ratio of Al to Sc. It represents a potential alternative to ferroelectric ceramic materials and ferroelectric hafnium-based oxides. Existing Al... x Sc 1- x Nitrogen thin films are commonly prepared using sputtering deposition. However, sputtering deposition has problems such as surface roughness, poor uniformity, and difficulty in precise control of composition due to high-energy particle bombardment and changes in target surface properties over time.

[0004] The search revealed:

[0005] Chinese invention patent application publication number CN113684536A discloses a physical vapor transport method for preparing Al. 1- x Sc x The method of using N crystals aims to achieve high concentrations of Sc doping, providing AlScN materials suitable for applications based on bulk acoustic waves and surface acoustic waves. However, it still cannot solve the problems mentioned above, such as surface roughness and difficulty in precise control of composition. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing AlScN thin films by atomic layer deposition.

[0007] According to one aspect of the present invention, an atomic layer deposition method for preparing Al is provided. 1-x Sc xA method for producing N-film (AlScN film), the method comprising:

[0008] Place the substrate into the deposition chamber;

[0009] After evacuating the deposition chamber to a preset pressure, the deposition chamber is heated, and carrier gas is constantly introduced into the deposition chamber.

[0010] A AlN deposition cycle is performed on the surface of the substrate;

[0011] Perform b cycles of ScN deposition;

[0012] Repeat the AlN deposition cycle a times and the ScN deposition cycle b times until the film reaches the target thickness. After cooling, Al is obtained. 1-x Sc x N thin film.

[0013] Furthermore, the preset pressure is less than 10 Pa.

[0014] Furthermore, the deposition chamber is heated and a carrier gas is constantly introduced into the deposition chamber, wherein the temperature of the deposition chamber is 200-500℃, the carrier gas is N2 or Ar, and the flow rate of the carrier gas is 10-100 sccm.

[0015] Furthermore, the AlN deposition cycle is performed a times, where a is an integer from 0 to 3.

[0016] Further, the process involves performing *a* AlN deposition cycles, wherein a single AlN deposition cycle comprises:

[0017] Al precursor is introduced into the deposition chamber, and after a set time is waited, excess precursor and byproducts are removed.

[0018] Nitrogen precursor is introduced into the deposition chamber, and after a set time is waited, excess precursor and byproducts are removed.

[0019] Furthermore, b ScN deposition cycles are performed, where b is an integer from 0 to 3.

[0020] Further, the process involves b ScN deposition cycles, wherein a single ScN deposition cycle comprises:

[0021] Sc precursor is introduced into the sedimentation chamber. After the introduction is completed, a set time is waited to remove excess precursor and byproducts.

[0022] Nitrogen precursor is introduced into the deposition chamber, and after a set time is waited, excess precursor and byproducts are removed.

[0023] Furthermore, the Al precursor is trimethylaluminum or aluminum chloride.

[0024] Furthermore, the Sc precursor is Sc( i PrAMD)3 or Sc(MeCp)3.

[0025] Furthermore, the N precursor is any one of ammonia, ammonia plasma, and nitrogen plasma.

[0026] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0027] The atomic layer deposition preparation of Al in this invention x Sc 1-x The method for N thin films fully utilizes the self-limiting growth principle of atomic layer deposition (ALD) to achieve precise atomic-scale control of film thickness. It also utilizes the periodic ratio control of AlN and ScN to achieve precise control of component ratio. Furthermore, it leverages the uniformity of ALD thin films to achieve the integration capability of three-dimensional structures. Attached Figure Description

[0028] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 Atomic layer deposition preparation of Al according to an embodiment of the present invention 1-x Sc x A flowchart illustrating the method for producing N thin films. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0031] This invention provides an atomic layer deposition method for preparing Al 1-x Sc x A method for producing N-film (AlScN film), the method comprising:

[0032] S1, Place the substrate into the deposition chamber;

[0033] S2, after evacuating the deposition chamber to the preset pressure, heat the deposition chamber and constantly introduce carrier gas into the deposition chamber;

[0034] S3, perform a AlN deposition cycles on the surface of the substrate;

[0035] S4, perform b cycles of ScN deposition;

[0036] S5, repeat the steps of AlN deposition cycle a and ScN deposition cycle x times until the film reaches the target thickness, then cool down to obtain Al 1-x Sc x N thin film; specifically, after film growth is complete, the film is cooled and the Al-coated film is removed. 1-x Sc x The substrate of the N thin film, that is, the Al grown on the substrate. 1-x Sc x N thin film. Due to repeating AlN deposition cycles a and ScN deposition cycles b, the resulting Al... 1-x Sc x In the N thin film, x = b / (a+b), the ratio of Al to Sc can be controlled based on the values ​​of a and b.

[0037] This invention utilizes atomic layer deposition (ALD) technology to prepare Al 1-x Sc x N-film atomic layer deposition (ALD) technology, due to its self-limiting growth method, can achieve precise control of composition and thickness, and in particular, it can achieve the integration of three-dimensional structures, making it more advantageous in three-dimensional memory.

[0038] In order to facilitate the flow of precursors and carrier gas, in some embodiments, the preset pressure is less than 10 Pa.

[0039] The deposition temperature is the process temperature window for self-limiting chemical reactions on the atomic layer deposition surface. The carrier gas flow rate controls the contact time and concentration between the precursor and the substrate. In some embodiments, the deposition chamber is heated and a carrier gas is constantly introduced into the deposition chamber, wherein: the temperature of the deposition chamber is 200-500°C, preferably 300°C; the carrier gas is N2 or Ar, and the flow rate of the carrier gas is 10-100 sccm, preferably 40 sccm.

[0040] In some embodiments, *a* AlN deposition cycles are performed, wherein: preferably, *a* is an integer from 0 to 3. In other embodiments, *a* may also be other values. A single AlN deposition cycle includes:

[0041] S31, introduce Al precursor into the deposition chamber, wait for a set time after introduction, and remove excess precursor and by-products.

[0042] S32, introduce N precursor into the deposition chamber, wait for a set time after introduction, and remove excess precursor and byproducts.

[0043] In some implementations, b ScN deposition cycles are performed, where b is an integer from 0 to 3; in other implementations, b can be other values. The ratio of Al to Sc is adjusted by controlling the values ​​of a and b.

[0044] A single ScN deposition includes:

[0045] S41, introduce Sc precursor into the sedimentation chamber, wait for a set time after introduction, and remove excess precursor and by-products.

[0046] S42, introduce N precursor into the deposition chamber, wait for a set time after introduction, and remove excess precursor and byproducts.

[0047] It should be noted that during the above deposition process, the waiting time after introducing the precursor is related to the cavity size, the pumping speed of the vacuum pump, and other conditions. The waiting time is similar for different precursors. Preferably, the waiting time after introducing the precursor is 10 seconds.

[0048] In some embodiments, the Al precursor is trimethylaluminum (TMA) or aluminum chloride. The Sc precursor is Sc( i PrAMD)3 or Sc(MeCp)3. The N precursor is any one of ammonia, ammonia plasma, and nitrogen plasma.

[0049] Atomic layer deposition preparation of Al in the above embodiments 1-x Sc x The method for N thin films fully utilizes the self-limiting growth principle of atomic layer deposition (ALD) to achieve precise atomic-scale control of film thickness. It also utilizes the periodic ratio control of AlN and ScN to achieve precise control of component ratios and leverages the uniformity of the film in the ALD process to achieve the integration capability of three-dimensional structures.

[0050] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0051] Reference Figure 1 The atomic layer deposition method for preparing Al provided in this embodiment 1-x Sc x The method for N thin films specifically includes the following steps:

[0052] 1) Place the substrate into the deposition chamber;

[0053] 2) Evacuate the sedimentation chamber to <10Pa, heat the sedimentation chamber to 300℃, and introduce a constant carrier gas into the sedimentation chamber. The carrier gas is N2 or Ar, and the flow rate is 40sccm.

[0054] 3) Perform a AlN deposition cycles, where a typically has a value of 0-3;

[0055] A single AlN deposition includes steps 3.1) to 3.2).

[0056] 3.1) Introduce Al precursor into the deposition chamber. The Al precursor is preferably trimethylaluminum or aluminum chloride. After introducing the precursor, wait for a set time to remove excess precursor and byproducts.

[0057] 3.2) Introduce N precursor into the deposition chamber and wait for a set time. During the waiting period, remove excess precursor and byproducts by introducing carrier gas and vacuuming.

[0058] 4) Perform b ScN deposition cycles, where b typically has a value of 0-3;

[0059] A single ScN deposition includes steps 4.1) to 4.2).

[0060] 4.1) Introduce Sc precursor into the sedimentation chamber. Sc precursor is preferably Sc( i PrAMD)3 and Sc(MeCp)3 are introduced and then wait for a set time. During the waiting process, excess precursors and byproducts are removed by introducing carrier gas and vacuuming.

[0061] 4.2) Introduce N precursor into the deposition chamber. The N precursor is preferably ammonia, ammonia plasma, or nitrogen plasma. After introducing the precursor, wait for a set time. During the waiting period, remove excess precursor and byproducts by introducing carrier gas and vacuuming.

[0062] 5) Repeat steps 3) and 4) multiple times, adjusting the ratio of Al and Sc by controlling the values ​​of a and b, and obtain Al after cooling. 1-x Sc x N thin film.

[0063] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention. The above preferred features can be used in any combination without conflict.

Claims

1. An atomic layer deposition method for preparing Al 1-x Sc x The method for N-thickness film is characterized by, include: Place the substrate into the deposition chamber; After evacuating the deposition chamber to a preset pressure, the deposition chamber is heated, and carrier gas is constantly introduced into the deposition chamber. A series of AlN deposition cycles are performed on the surface of the substrate, wherein a single AlN deposition cycle includes: Al precursor is introduced into the deposition chamber, and after a set time is waited, excess precursor and byproducts are removed. Introduce N precursor into the sedimentation chamber, wait for a set time after introduction, and remove excess precursor and byproducts. Perform b ScN deposition cycles, wherein a single ScN deposition cycle includes: Sc precursor is introduced into the sedimentation chamber. After the introduction is completed, a set time is waited to remove excess precursor and byproducts. Introduce N precursor into the sedimentation chamber, wait for a set time after introduction, and remove excess precursor and byproducts. Repeat the AlN deposition cycle a times and the ScN deposition cycle b times until the film reaches the target thickness. After cooling, Al is obtained. 1-x Sc x N thin film, x=b / (a+b).

2. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The preset pressure is less than 10 Pa.

3. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The deposition chamber is heated, and a carrier gas is constantly introduced into the deposition chamber, wherein the temperature of the deposition chamber is 200-500 ℃, the carrier gas is N2 or Ar, and the flow rate of the carrier gas is 10-100 sccm.

4. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The process involves performing *a* AlN deposition cycles, where *a* is an integer from 0 to 3.

5. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The process involves b ScN deposition cycles, where b is an integer from 0 to 3.

6. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The Al precursor is trimethylaluminum or aluminum chloride.

7. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The Sc precursor is Sc( i PrAMD)3 or Sc(MeCp)3.

8. The preparation of Al by atomic layer deposition according to claim 1 1-x Sc x The method for N-thickness film is characterized by, The N precursor is any one of ammonia, ammonia plasma, and nitrogen plasma.

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