Thin film deposition method with multi-angle gas inlet in ald cavity, al2o3 thin film and application

Abstract

The application provides a thin film deposition method with multi-angle gas inlet for an ALD cavity, an Al2O3 thin film and application, and relates to the technical field of atomic layer deposition (ALD). The thin film deposition method comprises the following steps: in a deposition process, a forward-in and backward-out gas supply mode and an upward-in and downward-out gas supply mode are alternately circulated to supply gas to the ALD cavity to perform thin film deposition, so that a deposition thin film is obtained. The application solves the technical problem of poor thickness uniformity of a thin film caused by the gas inlet mode of an ALD device in the prior art, and achieves the technical effects of improving the thickness uniformity of Al2O3 thin film deposition on a battery piece, making the Al2O3 thin film more dense, enhancing the passivation effect, and improving the battery conversion efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of atomic layer deposition (ALD), in particular to a thin film deposition method with multi-angle gas inlet for an ALD cavity, an Al2O3 thin film and application. BACKGROUND

[0002] Atomic layer deposition (ALD) is a technology that forms a deposition film by alternately introducing gas-phase precursors into a reactor and causing chemical reactions.

[0003] The Al2O3 thin film synthesized by the device for solar cell manufacturing has passivation properties, has two properties of field passivation and chemical passivation, can reduce the interface recombination rate, improve the minority carrier lifetime, and improve the conversion efficiency of the solar cell. Therefore, the uniformity of the Al2O3 thin film plays a key role in the conversion efficiency of the solar cell.

[0004] The existing ALD device gas inlet mode is to introduce gas into the cavity from the front end of the cavity for reaction, and the one-way gas transmission structure is to extract the reacted gas and impurities from the tail end of the cavity. Figure 1 That is, the front-end gas inlet and rear-end gas outlet (front-in rear-out) gas inlet mode, which will cause the Al2O3 thin film deposited on the upper and lower ends of the cell sheet to be thinner than the thickness on the left and right ends, resulting in poor thickness uniformity of the Al2O3 thin film, and further affecting the passivation effect of the Al2O3 on the cell sheet and reducing the conversion efficiency of the cell sheet.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] One of the purposes of the present application is to provide a thin film deposition method with multi-angle gas inlet for an ALD cavity, which can improve the thickness uniformity during thin film deposition, especially can effectively improve the thickness uniformity of Al2O3 thin film deposition, and can make the Al2O3 thin film more dense.

[0007] In order to achieve the above purpose of the present application, the following technical scheme is adopted:

[0008] A thin film deposition method with multi-angle gas inlet for an ALD cavity, comprising the following steps:

[0009] During the deposition process, the front-in rear-out and up-in down-out gas inlet modes are alternately circulated to supply gas to the ALD cavity for thin film deposition, thereby obtaining a deposited thin film.

[0010] Further, the thin film comprises an Al2O3 thin film.

[0011] Further, the gas supplied includes TMA and H2O.

[0012] Further, the temperature for the thin film deposition is 250-280 DEG C.

[0013] Further, the thin film deposition method includes the following steps:

[0014] First, the battery piece is sent into the ALD cavity, then the ALD cavity is supplied with gas by using the forward and backward gas supply mode to perform the first thin film deposition, then the ALD cavity is supplied with gas by using the upward and downward gas supply mode to perform the second thin film deposition, then the first thin film deposition and the second thin film deposition are cycled, thereby depositing the thin film on the battery piece.

[0015] Further, the time length of the first thin film deposition is 3-10s.

[0016] Further, the time length of the second thin film deposition is 3-10s.

[0017] Further, the total number of cycles is 20-35.

[0018] The thin film deposition method with multi-angle gas supply for the ALD cavity provided by the application increases the upward gas supply and downward gas extraction mode on the basis of the forward gas supply and backward gas extraction mode, and uses the two gas supply modes of forward and backward gas supply and upward and downward gas supply to alternately cycle for the gas supply in the ALD cavity during the whole deposition process, so that the gas can be supplied from different angles, the gas convection caused gas flow disorder in the cavity can be prevented, the thickness uniformity during the thin film deposition can be improved, especially the thickness uniformity of the Al2O3 thin film deposition can be effectively improved, the Al2O3 thin film is more uniform and dense, the passivation effect is enhanced, and the yield abnormality (dark piece, film explosion, etc.) caused by the non-uniform Al2O3 film can be improved.

[0019] The second object of the application is to provide an Al2O3 thin film deposited by using the thin film deposition method described in any one of the above, the Al2O3 thin film has good thickness uniformity, the thin film is dense, and the passivation effect on the battery piece is excellent, which is beneficial to improve the conversion efficiency of the battery piece.

[0020] The third object of the application is to provide the application of the Al2O3 thin film described above in the solar cell, which is beneficial to improve the conversion efficiency of the battery and has outstanding application effect. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0022] Figure 1 The gas inlet mode of the ALD cavity in the prior art;

[0023] Figure 2 The multi-angle gas inlet mode of the ALD cavity provided by an embodiment of the present application. EMBODIMENT

[0024] The technical solutions of the present application will be described below in connection with the embodiments, obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0025] According to a first aspect of the present application, a multi-angle gas inlet thin film deposition method for an ALD cavity is provided, comprising the following steps:

[0026] During the deposition process, the ALD cavity is supplied with gas by alternating circulation of the front-in back-out and the top-in bottom-out gas inlet modes to perform thin film deposition, thereby obtaining a deposited thin film.

[0027] The multi-angle gas inlet thin film deposition method for the ALD cavity provided by the present application, on the basis of the front-in back-out gas inlet mode, increases the top-in bottom-out gas inlet mode. During the entire deposition process, the ALD cavity is supplied with gas by alternating circulation of the front-in back-out and the top-in bottom-out gas inlet modes. In this way, the gas can be provided from different angles, the gas convection caused by the gas flow disorder in the cavity can be prevented, the thickness uniformity during the thin film deposition can be improved, especially the thickness uniformity of the Al2O3 thin film deposition can be effectively improved, the Al2O3 thin film thickness is more uniform and dense, the passivation effect is enhanced, and the yield abnormality (dark film, film explosion, etc.) caused by the non-uniform Al2O3 film deposition can be improved.

[0028] In a preferred embodiment, in the process of Al2O3 thin film deposition, the gas supplied into the ALD cavity includes but is not limited to TMA and H2O, which is more conducive to further improving the thickness uniformity of the Al2O3 thin film deposition, and making the Al2O3 thin film thickness more uniform and dense.

[0029] In a preferred embodiment, the process temperature during deposition of the Al2O3 film can be 250-280°C, and a typical but non-limiting process temperature can be, for example, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, which is more conducive to further improving the effect of deposition of the Al2O3 film.

[0030] In a preferred embodiment, the film deposition method of the present application comprises the following steps:

[0031] First, the battery piece is sent into the ALD cavity, and then the ALD cavity is supplied with gas (TMA and H2O) in a forward-backward air supply mode (front-end gas inlet and rear-end gas outlet) to perform first film deposition, and then the ALD cavity is supplied with gas (TMA and H2O) in an upward-downward air supply mode (upper-end gas inlet and lower-end gas outlet) to perform second film deposition, as shown in Figure 2 Then, the above-mentioned first film deposition and second film deposition processes are cycled to deposit and form an Al2O3 film on the battery piece.

[0032] In the present application, the first film deposition is performed in the forward-backward air supply mode for 3-10s, for example, 3s, 4s, 5s, 6s, 7s, 8s, 9s, or 10s, but not limited thereto, and the second film deposition is performed in the upward-downward air supply mode for 3-10s, for example, 3s, 4s, 5s, 6s, 7s, 8s, 9s, or 10s, but not limited thereto.

[0033] In a preferred embodiment, the total deposition time of the first film deposition and the second film deposition can be regarded as one cycle, and a total of 20-35 cycles can be run to complete the deposition of the Al2O3 film, which is more conducive to further forming an Al2O3 film with uniform thickness and density on the battery piece.

[0034] In summary, the present application uses the forward-backward and upward-downward multi-angle air supply modes, and the two air supply modes are alternately cycled, which can deposit an Al2O3 film with uniform thickness on the battery piece, and completely solves the technical problem of poor film deposition thickness uniformity caused by the ALD equipment air supply mode (one-way gas transmission) in the prior art. Under the synergistic cooperation of various process parameters, the Al2O3 film is deposited more densely, thereby improving the passivation effect on the battery piece and improving the conversion efficiency of the battery piece.

[0035] According to a second aspect of the present application, there is provided an Al2O3 film deposited by the thin film deposition method of any one of the above, which has good thickness uniformity, good film density, and excellent passivation effect on the battery piece, and is more conducive to improving the conversion efficiency of the battery piece than the Al2O3 film deposited by the prior art.

[0036] According to a third aspect of the present application, there is provided an application of the Al2O3 film of the above in a solar cell, which is conducive to improving the conversion efficiency of the battery and has outstanding application effect.

[0037] The present application will be further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to the existing method or directly purchased from the market.

[0038] Example 1

[0039] A thin film deposition method of ALD cavity multi-angle gas inlet, comprising the following steps:

[0040] Step 1: The process starts running, and the aluminum boat loaded with battery pieces enters the ALD cavity;

[0041] Step 2: The cavity starts to warm up to a process temperature of 250℃;

[0042] Step 3: The reaction required gases TMA and H2O are introduced into the ALD cavity to start the reaction and deposition of Al2O3 film on the battery piece;

[0043] The deposition mode is as follows: first, the front-in and rear-out (i.e. front-end gas inlet and rear-end gas outlet) gas inlet mode is used for deposition for 5s, and then the upper-in and lower-out (i.e. upper-end gas inlet and lower-end gas outlet) gas inlet mode is used for deposition for 5s, and the above two depositions are a cycle, and a total of 28 cycles are run;

[0044] Step 4: The Al2O3 film deposition is completed, the nitrogen gas is used to purge the cavity to restore the normal pressure, and the boat is discharged to end the process.

[0045] Comparative Example 1

[0046] This comparative example provides a thin film deposition method, compared with Example 1, in Step 3, only the front-in and rear-out gas inlet mode is used to deposit Al2O3 film on the battery piece, and 10s of deposition is a cycle, and a total of 28 cycles are run;

[0047] The rest is the same as Example 1, and the Al2O3 film is obtained.

[0048] Compared with Example 1, the present comparative example uses cavity front end ventilation into the cavity for reaction, and the one-way gas transmission of the reaction gas and impurities extracted from the tail end of the cavity, which results in the thickness of the Al2O3 film deposited on the upper and lower ends of the battery sheet being thinner, and the thickness of the Al2O3 film on the left and right ends being different, which causes the thickness uniformity of the Al2O3 film to be poor, and affects the passivation effect of Al2O3 on the battery sheet.

[0049] Comparative Example 2

[0050] The present comparative example provides a thin film deposition method. Compared with Example 1, the present comparative example only uses the upper-in and lower-out ventilation method in step 3 to deposit Al2O3 film on the battery sheet, and the deposition of 10s is one cycle, and a total of 28 cycles are run.

[0051] The rest is the same as Example 1, and Al2O3 film is obtained.

[0052] Compared with Example 1, the defect of the present comparative example is that the inter-sheet uniformity and intra-sheet uniformity of the Al2O3 film sheet are poor.

[0053] Test Example

[0054] The Al2O3 films obtained in the test examples and comparative examples are tested, and the results are shown in Table 1.

[0055] Test method: The thickness of the Al2O3 film is tested using a spectroscopic ellipsometer.

[0056] Table 1

[0057]

[0058] As can be seen, in the ALD technology, the present application uses the two ventilation methods of forward and backward and upper-in and lower-out to alternately circulate the gas supply in the ALD cavity, which can provide gas from different angles, prevent the problem of gas convection causing turbulence of the gas flow in the cavity, and more effectively improve the thickness uniformity of the Al2O3 film deposition, form an Al2O3 film with uniform thickness and density, strengthen the passivation effect, and help to improve the conversion efficiency of the battery sheet. At the same time, it can also effectively improve the yield abnormality (dark sheet, film explosion, etc.) problem caused by the non-uniformity of Al2O3 plating film.

[0059] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thin film deposition method with multi-angle air intake in an ALD cavity, characterized in that, The method comprises the following steps: The battery piece is first sent into an ALD cavity, then the ALD cavity is supplied with air in a forward-backward air supply mode to perform first film deposition, then the ALD cavity is supplied with air in an upward-downward air supply mode to perform second film deposition, then the first film deposition and the second film deposition are cycled to deposit and form a film on the battery piece; The first film deposition lasts for 3-10 seconds; the second film deposition lasts for 3-10 seconds; and the total number of cycles is 20-35. The film comprises an Al2O3 film. In the first film deposition, the supplied air comprises TMA and H2O. In the second film deposition, the supplied air comprises TMA and H2O.

2. The thin film deposition method of claim 1, wherein, The film deposition temperature is 250-280°C.

3. An Al2O3 film deposited by the film deposition method of claim 1 or 2.

4. Application of the Al2O3 film of claim 3 to a solar cell.

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