Method for improving quality of gate oxide layer

Abstract

The invention provides a method for improving the quality of a gate oxide layer, and the method comprises the steps: providing a substrate, and forming a gate oxide layer on the substrate; performing ion implantation on the surface of the gate oxide layer, wherein the implanted ions are consistent with semiconductor elements contained in the material of the gate oxide layer; and carrying out rapid heat treatment on the gate oxide layer in an inert gas and oxygen atmosphere, so that ions injected into the gate oxide layer react with oxygen to improve the surface quality of the gate oxide layer. According to the method, ion implantation is carried out on the surface of the gate oxide layer, and rapid heat treatment is carried out in the inert gas and oxygen atmosphere, so that ions implanted on the surface of the gate oxide layer react with oxygen to form a more compact surface, and the surface quality of the gate oxide layer is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for improving the quality of gate oxide layers. Background Technology

[0002] Currently, most gate oxide growth methods in medium-voltage (MV) and high-voltage (HV) devices employ thermal oxidation. While this method shortens the gate oxide growth time, it also introduces quality issues, leading to higher losses in subsequent processes. For example, poor surface quality and a loose surface due to rapid growth result in wasted photoresist (PR) layer during removal, further deteriorating the already low-quality gate oxide. Furthermore, the poor quality gate oxide can cause photoresist migration or peeling defects. Even repeated washing with pure water fails to achieve adequate separation between the photoresist and the gate oxide surface, highlighting the urgent need for improvement in this area. Summary of the Invention

[0003] The purpose of this invention is to provide a method for improving the quality of the gate oxide layer, which can improve the surface quality of the gate oxide layer, solve the problem of photoresist layer migration or peeling caused by gate oxide layer quality issues, and reduce the loss of the gate oxide layer in subsequent processes.

[0004] To address the aforementioned technical problems, this invention provides a method for improving the quality of a gate oxide layer, comprising the following steps:

[0005] A substrate is provided, on which a gate oxide layer is formed;

[0006] Ion implantation is performed on the surface of the gate oxide layer, and the implanted ions are consistent with the semiconductor elements contained in the gate oxide layer material; and

[0007] The gate oxide layer is subjected to rapid thermal treatment in an inert gas and oxygen atmosphere, so that the ions injected into the surface of the gate oxide layer react with oxygen to improve the surface quality of the gate oxide layer.

[0008] Optionally, the gate oxide layer is made of silicon oxide, and the ions implanted on the surface of the gate oxide layer include silicon ions, which react with oxygen to form silicon oxide.

[0009] Optionally, the depth of ion implantation is one-quarter to one-third of the thickness of the gate oxide layer.

[0010] Optionally, the ion implantation energy is greater than or equal to 2 keV and less than or equal to 5 keV, and the ion implantation dose is greater than or equal to 5E15 cm⁻¹.-2 Less than or equal to 1E16 cm -2 .

[0011] Optionally, nitrogen gas is also introduced during the rapid thermal treatment of the gate oxide layer.

[0012] Optionally, the volume ratio of the inert gas, the nitrogen, and the oxygen is 9:X:1-X, wherein X is greater than or equal to 0.4 and less than or equal to 0.7.

[0013] Optionally, the temperature of the rapid heat treatment is greater than or equal to 500°C and less than or equal to 800°C, and the time of the rapid heat treatment is greater than or equal to 30s and less than or equal to 90s.

[0014] Optionally, after the gate oxide layer is formed but before ion implantation is performed on the surface of the gate oxide layer, the method further includes: performing SPM cleaning on the surface of the gate oxide layer.

[0015] Optionally, after SPM cleaning of the gate oxide layer surface and before ion implantation of the gate oxide layer surface, the method further includes cleaning the gate oxide layer surface with pure water.

[0016] Optionally, the gate oxide layer may be formed using a high-temperature oxidation process.

[0017] In summary, the method for improving the quality of the gate oxide layer provided by this invention first involves providing a substrate on which a gate oxide layer is formed; then, ion implantation is performed on the surface of the gate oxide layer, wherein the implanted ions are identical to the semiconductor elements contained in the material of the gate oxide layer; subsequently, the gate oxide layer is subjected to rapid thermal treatment in an inert gas and oxygen atmosphere, causing the implanted ions in the gate oxide layer to react with oxygen to improve the surface quality of the gate oxide layer. This invention improves the surface quality of the gate oxide layer by performing ion implantation on the surface of the gate oxide layer and then rapid thermal treatment in an inert gas and oxygen atmosphere, causing the implanted ions on the surface of the gate oxide layer to react with oxygen to form a denser surface.

[0018] Furthermore, in this invention, the gate oxide layer is made of silicon oxide, and the ions implanted on the surface of the gate oxide layer include silicon ions. The silicon ions react with oxygen to form an oxide layer, thereby improving the surface quality of the gate oxide layer. Simultaneously, the gate oxide layer is subjected to rapid heat treatment in an inert gas and oxygen atmosphere, which breaks down the Si-OH and Si-H bonds within the gate oxide layer, forming a Si-O bond network. The large-angle Si-O-Si bonds transform into a more stable small-angle or network structure, while the cross-linking structure is improved, thus enhancing the quality of the gate oxide layer.

[0019] Furthermore, nitrogen gas was introduced into the atmosphere where the gate oxide layer underwent rapid thermal treatment, which increased the electrochemical thickness of the gate oxide layer without changing the physical thickness. In addition, the volume ratio of the inert gas, the nitrogen gas, and the oxygen gas was 9:X:1-X, meaning a small amount of oxygen was introduced, and both the pressure and gas flow remained low, thus slowly forming a high-quality gate oxide layer while reducing the oxidation of the substrate beneath the gate oxide layer by oxygen.

[0020] Furthermore, after forming the gate oxide layer, before ion implantation, the surface of the gate oxide layer is subjected to SPM cleaning. SPM cleaning removes chloride ions, which act as a catalyst during the surface oxidation process of the gate oxide layer. This prevents chloride ions from reacting with the photoresist during subsequent rapid thermal processing, thus avoiding photoresist residue buildup or migration, improving the quality of the gate oxide layer, and reducing subsequent gate oxide layer loss. Simultaneously, it avoids the superposition of silicon oxide reactions at the residual sites of the precursor during re-oxidation, preventing surface inhomogeneity caused by the reaction, and improving the uniformity of surface oxidation.

[0021] In addition, the gate oxide layer on the surface is modified by rapid thermal treatment in this invention, so that the subsequent photoresist layer can be safely formed on the gate oxide layer. The surface of the gate oxide layer is more dense, which can prevent excessive consumption of the gate oxide layer surface when the photoresist layer is patterned in the future.

[0022] This invention employs a high-temperature oxidation process to rapidly form a gate oxide layer, while also providing a high-quality gate oxide layer surface, balancing speed and quality. It also allows for better patterning of the photoresist layer, and after the photoresist layer is removed, the surface of the photoresist layer is relatively dense and will not be roughened, thus ensuring the quality of the gate oxide layer. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for improving the quality of a gate oxide layer according to an embodiment of the present invention.

[0024] Figures 2 to 4 This is a schematic diagram of the steps in a method for improving the quality of a gate oxide layer according to an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10-Substrate; 11-Active region; 12-Shallow trench isolation structure; 20-Gate oxide layer; 21-Gate oxide layer implanted with silicon ions. Detailed Implementation

[0027] Methods for forming the gate oxide layer include, but are not limited to, wet oxidation, dry oxidation, and in-situ steam generation (ISSG). Wet oxidation involves introducing water vapor as an oxidant into a reaction chamber at high temperature to react with the surface of the semiconductor substrate 100 and form the gate oxide layer; wet oxidation has a relatively fast growth rate. Dry oxidation involves introducing dry, pure oxygen into a reaction chamber at high temperature to react with the surface of the semiconductor substrate 100 and form the gate oxide layer; dry oxidation can form oxide films with high uniformity and density. ISSG involves introducing hydrogen and oxygen into a reaction chamber at high temperature in a certain proportion. The hydrogen and oxygen react chemically at high temperature to generate a large number of gaseous active free radicals, the main component of which is oxygen atom free radicals. Due to the strong oxidizing effect of oxygen atom free radicals, they react with silicon on the surface of the semiconductor substrate to form the gate oxide layer. The gate oxide layer 110 obtained using the ISSG process has fewer bulk defects and a relatively low interface state density.

[0028] To achieve a relatively high growth rate, a wet oxidation method is used to form the gate oxide layer. However, due to the rapid growth rate, the surface of the gate oxide layer becomes relatively loose. When forming a photoresist layer on the gate oxide layer and patterning it, this loose surface leads to wasted photoresist. Furthermore, during photoresist removal, the loose surface results in the removal of even more surface gate oxide layer. Additionally, a poor-quality gate oxide layer can cause photoresist layer migration or peeling.

[0029] To address the aforementioned problems, the present invention provides a method for improving the quality of a gate oxide layer, comprising: providing a substrate and forming a gate oxide layer on the substrate; performing ion implantation on the surface of the gate oxide layer, wherein the implanted ions are consistent with the semiconductor elements contained in the gate oxide layer material; and performing rapid thermal treatment on the gate oxide layer in an inert gas and oxygen atmosphere, such that the implanted ions in the surface of the gate oxide layer react with oxygen to improve the surface quality of the gate oxide layer.

[0030] This invention improves the surface quality of the gate oxide layer by performing ion implantation on the surface of the gate oxide layer and rapid heat treatment in an inert gas and oxygen atmosphere, so that the implanted ions react with oxygen to form a denser surface.

[0031] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0032] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to mean “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to mean “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to mean “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.

[0033] Figure 1 This is a flowchart of a method for improving the quality of a gate oxide layer according to an embodiment of the present invention. Figure 1 As shown, the method for improving the quality of the gate oxide layer provided in this embodiment of the invention includes the following steps:

[0034] S1: Provide a substrate on which a gate oxide layer is formed;

[0035] S2: Ion implantation is performed on the surface of the gate oxide layer, wherein the implanted ions are consistent with the semiconductor elements contained in the material of the gate oxide layer; and

[0036] S3: The gate oxide layer is subjected to rapid heat treatment in an inert gas and oxygen atmosphere, so that the ions injected into the surface of the gate oxide layer react with oxygen to improve the surface quality of the gate oxide layer.

[0037] Figures 2 to 4 This is a schematic diagram of the steps in a method for improving the quality of a gate oxide layer according to an embodiment of the present invention. Next, we will combine... Figure 1 and Figures 2 to 4 The method for improving the quality of the gate oxide layer provided in the embodiments of the present invention will be described in detail.

[0038] In step S1, please refer to Figure 1 As shown, a substrate 10 is provided, on which a gate oxide layer 20 is formed.

[0039] In this embodiment, the substrate 10 can be made of silicon, germanium, germanium-silicon, silicon carbide, gallium arsenide, or indium gallium arsenide, or it can be silicon-on-insulator or germanium-on-insulator; or it can be other materials, such as gallium arsenide or other III-V compounds. In this embodiment, the substrate 10 is preferably made of silicon.

[0040] In one embodiment of the present invention, a plurality of shallow trench isolation structures 12 are formed in the substrate 10, and the shallow trench isolation structures 12 divide the substrate 10 into a plurality of active regions 11.

[0041] A gate oxide layer 20 is formed on the substrate 10, covering the substrate 10. In one embodiment of the present invention, the gate oxide layer 20 is formed using a high-temperature oxidation (HTO) process. The gate oxide layer 20 can be a single-layer structure or a double-layer structure. If it is a double-layer structure, the thickness can be different, which can be determined according to the specific requirements of the device. For example, for an MV device, two gate oxide layers 20 are formed on the substrate 10, and the thickness of the first gate oxide layer 20 is... The thickness of the second gate oxide layer 20 is In this embodiment, a chlorine-containing element is used as a catalyst in the process of forming the gate oxide layer 20.

[0042] The gate oxide layer 20 is formed by oxidizing the substrate 10 with oxygen, and the semiconductor elements contained in the material of the gate oxide layer 20 are the same as those contained in the substrate 10. In one embodiment of the present invention, the material of the substrate 10 is silicon, then the semiconductor element contained in the material of the gate oxide layer 20 is silicon, and the material of the gate oxide layer 20 is silicon oxide.

[0043] In step S2, please refer to Figure 3 As shown, ion implantation is performed on the surface of the gate oxide layer 20, and the implanted ions are consistent with the semiconductor elements contained in the material of the gate oxide layer 20.

[0044] In one embodiment of the present invention, before ion implantation, the method further includes: performing SPM cleaning on the surface of the gate oxide layer 20 to remove particles and residual chlorine-containing organic matter from the surface of the gate oxide layer 20.

[0045] The gate oxide layer 20 is formed by reacting the precursors H4Si2Cl2 and O2 at high temperature in a furnace tube, resulting in the reaction H4Si2Cl2 + O2 = SiO2 + HCl. After the reaction, the inventors speculate that H and Cl ions may remain on the surface of the gate oxide layer. These chloride ions may react with solvents or additives in the photoresist, potentially interfering with the structure of the optical polymers in the photoresist, thus exacerbating the incomplete separation of the photoresist and the gate oxide layer. If H4Si2Cl2 (organic matter) remains, pure water is ineffective at removing this substance.

[0046] The surface of the gate oxide layer 20 can be cleaned using SPM (a mixture of sulfuric acid and hydrogen peroxide) to thoroughly remove residual H4Si2Cl2 (organic matter). In this embodiment, SPM cleaning removes chloride-containing organic matter, which serves as a precursor in the oxidation process of the gate oxide layer 20, thus preventing chloride ions from reacting with the photoresist during subsequent rapid thermal processing, which could lead to the photoresist becoming unremovable or migrating. This improves the quality of the gate oxide layer 20 and reduces subsequent losses. Simultaneously, it avoids the superposition of silicon oxide reactions at the residual sites of the precursor during re-oxidation, preventing surface inhomogeneity caused by the reaction, and improving the uniformity of surface oxidation.

[0047] In one embodiment of the present invention, after wet cleaning the surface of the gate oxide layer 20 and before ion implantation, the method further includes cleaning the surface of the gate oxide layer 20 with pure water to remove residual SPM (dissolved in pure water).

[0048] Ion implantation is performed on the surface of the gate oxide layer 20. The implanted ions are consistent with the semiconductor elements contained in the gate oxide layer 20 material, so that the reactants formed by the subsequent reaction of the implanted ions with oxygen are consistent with the material of the gate oxide layer 20, thereby improving the quality of the gate oxide layer 20. In one embodiment of the present invention, the material of the gate oxide layer 20 is silicon oxide, and the implanted ions are silicon ions. That is, silicon ion implantation is performed on the surface of the gate oxide layer 20. The silicon ion implantation into the gate oxide layer can fill the originally relatively loose gate oxide layer with more silicon ions, so that a denser oxide surface layer can be achieved after subsequent oxidation of this part of silicon.

[0049] Please refer to Figure 3 As shown, ion implantation is performed on the surface of the gate oxide layer 20 to form a gate oxide layer 21 implanted with silicon ions within the surface of the gate oxide layer 20. In one embodiment of the present invention, the ion implantation depth is one-quarter to one-third of the thickness of the gate oxide layer 20, that is, the ion implantation depth is greater than or equal to one-quarter of the thickness of the gate oxide layer 20 and less than or equal to one-third of the thickness of the gate oxide layer 20. Of course, it is not limited to this. The ion implantation depth should not be too thick because the poor quality of the gate oxide layer surface brings about various undesirable problems in contact with the PR (Polymerization Process). Therefore, only surface treatment is required. If the entire gate oxide layer is ion implanted, it may penetrate the gate oxide layer and enter the active region of the substrate. This could lead to the formation of more severe oxidation on the substrate surface in subsequent steps, especially in hot and oxygen-rich environments, which is undesirable and will lead to uncontrollable results.

[0050] Furthermore, implanting only into a shallower surface layer is also beneficial because subsequent targets are only the surface portion of the gate oxide layer. For example, it is easier to control the re-oxidation process of the treated upper region. For instance, after surface silicon ion implantation, the surface of the gate oxide layer can be further oxidized by annealing in an oxygen atmosphere (to achieve a denser surface layer). The gate oxide layer without implanted silicon ions can serve as a protective layer or barrier layer for the active region of the bottom substrate (to prevent the silicon substrate from being re-oxidized during the surface oxidation process), thus protecting the substrate and avoiding the consumption of implanted ions in the source / drain region or the threshold voltage ion implantation region or the well region in the substrate.

[0051] The gate oxide layer 21 implanted with silicon ions is a region with high silicon concentration. During subsequent rapid thermal processing, silicon reacts with oxygen to further form the gate oxide layer 20, thereby forming a denser gate oxide layer 20 surface and improving the surface quality of the gate oxide layer 20.

[0052] In one embodiment of the present invention, when the gate oxide layer 20 comprises two gate oxide layers, ion implantation is only required on the surface of the top gate oxide layer 20. For example, when the thickness of the top gate oxide layer 20 is... When the ion implantation depth is greater than or equal to Less than or equal to

[0053] In one embodiment of the present invention, low-energy, high-dose ion implantation is used. For example, the ion implantation energy is greater than or equal to 2 keV and less than or equal to 5 keV, and the ion implantation dose is greater than or equal to 5E15cm. -2 Less than or equal to 1E16cm -2 Of course, it's not limited to that. Low-energy, high-dose ion implantation is used to obtain a denser gate oxide surface later.

[0054] In step S3, please refer to Figure 4 As shown, the gate oxide layer 20 is subjected to rapid heat treatment in an inert gas and oxygen atmosphere, so that the ions injected on the surface of the gate oxide layer 20 react with oxygen to improve the surface quality of the gate oxide layer 20.

[0055] The present invention improves the surface quality of the gate oxide layer 20 by performing ion implantation on the surface of the gate oxide layer 20 and rapid heat treatment in an inert gas and oxygen atmosphere, so that the implanted ions react with oxygen to form a denser surface.

[0056] In one embodiment of the present invention, the gate oxide layer 20 is made of silicon oxide, and the ions implanted on the surface of the gate oxide layer 20 include silicon ions. The silicon ions react with oxygen to form an oxide layer, thereby improving the quality of the gate oxide layer. Simultaneously, the gate oxide layer 20 is subjected to rapid heat treatment in an inert gas and oxygen atmosphere, which breaks the Si-OH and Si-H bonds within the gate oxide layer 20, forming a Si-O bond network. The large-angle Si-O-Si bonds transform into a more stable small-angle or network structure, and the cross-linking structure is improved, thus enhancing the quality of the gate oxide layer 20.

[0057] In one embodiment of the present invention, the gas atmosphere for rapid thermal treatment also includes nitrogen, which increases the electrochemical thickness of the gate oxide layer 20 without changing the physical thickness.

[0058] The volume ratio of the inert gas, the nitrogen, and the oxygen is 9:X:1-X, where X < 1. This means that a small amount of oxygen is introduced, and both the pressure and the gas flow are kept low, thereby slowly forming a high-quality gate oxide layer 20 while reducing the oxidation of the substrate 10 at the bottom of the gate oxide layer 20 by oxygen. In one embodiment of the present invention, X is greater than or equal to 0.4 and less than or equal to 0.7, but is not limited thereto.

[0059] In one embodiment of the present invention, the temperature of the rapid heat treatment is greater than or equal to 500°C and less than or equal to 800°C, and the time of the rapid heat treatment is greater than or equal to 30 seconds and less than or equal to 90 seconds. Of course, it is not limited to this.

[0060] In one embodiment of the present invention, after rapid thermal annealing, the method further includes: forming a photoresist layer on the gate oxide layer 20, and then performing exposure and development to form a patterned photoresist layer. In this invention, rapid thermal processing modifies the gate oxide layer 20, enabling the photoresist layer to be safely formed on the gate oxide layer 20. Furthermore, the surface of the gate oxide layer 20 is more dense, preventing excessive wear of the gate oxide layer 20 surface during patterning.

[0061] In this embodiment of the invention, a high-temperature oxidation is used to rapidly grow the gate oxide layer 20, which also provides a higher quality gate oxide layer 20 surface, balancing speed and quality. At the same time, it allows for better patterning of the photoresist layer. Furthermore, after the photoresist layer is removed, the surface of the gate oxide layer 20 is dense and will not be roughened, thus ensuring the quality of the gate oxide layer.

[0062] It should be noted that when the quality of the gate oxide layer is poor, but a photoresist layer needs to be formed on the gate oxide layer, the above method can be used to improve the surface quality of the gate oxide layer. If photoresist is not needed on the gate oxide layer, but the quality of the gate oxide layer is poor, the above method can also be used for improvement. In this embodiment, the thickness of the improved gate oxide layer can be determined by changing the ion implantation depth, but at the same time, it is necessary to avoid oxidation of the substrate below the gate oxide layer.

[0063] In summary, the method for improving the quality of the gate oxide layer provided by this invention first involves providing a substrate on which a gate oxide layer is formed; then, ion implantation is performed on the surface of the gate oxide layer, wherein the implanted ions are identical to the semiconductor elements contained in the material of the gate oxide layer; subsequently, the gate oxide layer is subjected to rapid thermal treatment in an inert gas and oxygen atmosphere, causing the implanted ions in the gate oxide layer to react with oxygen to improve the surface quality of the gate oxide layer. This invention improves the surface quality of the gate oxide layer by performing ion implantation on the surface of the gate oxide layer and then rapid thermal treatment in an inert gas and oxygen atmosphere, causing the implanted ions on the surface of the gate oxide layer to react with oxygen to form a denser surface.

[0064] Furthermore, in this invention, the gate oxide layer is made of silicon oxide, and the ions implanted on the surface of the gate oxide layer include silicon ions. The silicon ions react with oxygen to form an oxide layer, thereby improving the surface quality of the gate oxide layer. Simultaneously, the gate oxide layer is subjected to rapid heat treatment in an inert gas and oxygen atmosphere, which breaks down the Si-OH and Si-H bonds within the gate oxide layer, forming a Si-O bond network. The large-angle Si-O-Si bonds transform into a more stable small-angle or network structure, while the cross-linking structure is improved, thus enhancing the quality of the gate oxide layer.

[0065] Furthermore, nitrogen gas was introduced into the atmosphere where the gate oxide layer underwent rapid thermal treatment, which increased the electrochemical thickness of the gate oxide layer without changing the physical thickness. In addition, the volume ratio of the inert gas, the nitrogen gas, and the oxygen gas was 9:X:1-X, meaning a small amount of oxygen was introduced, and both the pressure and gas flow remained low, thus slowly forming a high-quality gate oxide layer while reducing the oxidation of the substrate beneath the gate oxide layer by oxygen.

[0066] Furthermore, after forming the gate oxide layer and before ion implantation, the surface of the gate oxide layer is subjected to SPM cleaning. SPM cleaning removes organic matter containing chloride ions, which are precursors in the gate oxide surface oxidation process. This prevents chloride ions from reacting with the photoresist during subsequent rapid thermal processing, thus avoiding photoresist residue buildup or migration and improving the quality of the gate oxide layer, reducing subsequent gate oxide layer loss. Simultaneously, it avoids the superposition of silicon oxide reactions at the residual sites of the precursor during re-oxidation, preventing surface inhomogeneity caused by the reaction, and improving the uniformity of surface oxidation.

[0067] In addition, the gate oxide layer on the surface is modified by rapid thermal treatment in this invention, so that the subsequent photoresist layer can be safely formed on the gate oxide layer. The surface of the gate oxide layer is more dense, which can prevent excessive consumption of the gate oxide layer surface when the photoresist layer is patterned in the future.

[0068] This invention employs a high-temperature oxidation process to rapidly form a gate oxide layer, while also providing a high-quality gate oxide layer surface. This allows the photoresist layer to be better patterned, and after the photoresist layer is removed, the surface of the photoresist layer is relatively dense and will not be roughened, thus ensuring the quality of the gate oxide layer.

[0069] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method of improving gate oxide quality, comprising: The method comprises the following steps: providing a substrate, and forming a gate oxide layer on the substrate; carrying out ion implantation on the surface of the gate oxide layer, the implanted ions being consistent with the semiconductor elements contained in the material of the gate oxide layer; and carrying out rapid thermal treatment on the gate oxide layer in an inert gas and oxygen atmosphere, so that the implanted ions in the surface of the gate oxide layer react with oxygen to improve the surface quality of the gate oxide layer.

2. The method of claim 1, wherein the gate oxide quality is improved by: The material of the gate oxide layer comprises silicon oxide, and the implanted ions in the surface of the gate oxide layer comprise silicon ions, which react with oxygen to form silicon oxide.

3. The method of claim 1, wherein the gate oxide quality is improved by: The depth of the ion implantation is one fourth to one third of the thickness of the gate oxide layer.

4. The method of claim 3, wherein the gate oxide quality is improved by: The ion implantation has an energy greater than or equal to 2 Kev and less than or equal to 5 Kev, and a dose greater than or equal to 5E15 cm -2 and less than or equal to 1E16 cm -2 .

5. The method of claim 1, wherein the gate oxide quality is improved by: Nitrogen is also introduced when the rapid thermal treatment is carried out on the gate oxide layer.

6. The method of claim 6, wherein the gate oxide quality is improved by: The volume ratio of the inert gas, the nitrogen and the oxygen is 9:X:1-X, wherein X is greater than or equal to 0.4 and less than or equal to 0.

7.

7. The method of claim 1, wherein the gate oxide quality is improved by: The temperature of the rapid thermal treatment is greater than or equal to 500 DEG C and less than or equal to 800 DEG C, and the time of the rapid thermal treatment is greater than or equal to 30 s and less than or equal to 90 s.

8. The method of improving gate oxide quality according to any one of claims 1 to 7, wherein, After the gate oxide layer is formed, before the ion implantation is carried out on the surface of the gate oxide layer, the method further comprises carrying out SPM cleaning on the surface of the gate oxide layer.

9. The method of claim 8, wherein the gate oxide quality is improved by: After the SPM cleaning is carried out on the surface of the gate oxide layer, before the ion implantation is carried out on the surface of the gate oxide layer, the method further comprises cleaning the surface of the gate oxide layer with pure water.

10. The method of improving gate oxide quality according to any one of claims 1 to 7, wherein, The gate oxide layer is formed by using a high-temperature oxidation process.

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