Method for generating defect structure of single crystal silicon oxide layer based on simulation of actual process

Abstract

The present invention provides a method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process, which relates to the field of semiconductor material computational simulation technology, and includes the following steps: Step S1: constructing an interface structure of a single crystal silicon oxide layer using defect property simulation software according to process parameters of an actual thermal oxidation process; identifying and deleting molecules in the voids of the interface structure and molecules in the vacuum layer; Step S2: intercepting an independent structure within the depth range of the interface structure to be counted, identifying and counting structural parameters in the independent structure, wherein the structural parameters include defect density and defect type. The present invention grasps the structural features in the independent structure through structural parameters, which is conducive to accurately grasping important structural features such as defect density and defect type of a disordered system, and is of great significance for establishing a connection relationship between microscopic structures such as defects and macroscopic preparation processes or semiconductor devices.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor material computational simulation, and in particular to a method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process. Background Art

[0002] The semiconductor oxide layer is not only a masking layer for ion implantation or thermal diffusion, but also a passivation layer to ensure the surface of the device; it is not only an insulating layer for electrical isolation between devices, but also a major component to ensure electrical isolation in MOS processes and multi-layer metallization systems. The charge and interface state defects in the oxide layer are important defect types that affect the performance and life of silicon-based semiconductor electronic components. The defect concentration and state in devices of different models are mainly controlled by the generation and processing technology of the oxide layer. Therefore, studying the influence of process parameters on the defect properties of the interface structure generated by silicon oxidation is extremely important for understanding the growth mechanism of the oxide layer, optimizing the growth process of the oxide layer, and stably generating high-quality oxide layers, which is necessary to ensure the reliability of high-quality integrated circuits.

[0003] With the continuous improvement of computing power, the simulation of thermal oxidation process at the atomic scale has become a hot research field in the growth control of silicon-based semiconductors. The simulation of oxide layer growth process based on quantum mechanics and molecular dynamics can make up for the shortcomings of experiments, such as high detection cost, long preparation and analysis cycle, and the inability of experimental results to directly reflect the structural conditions of defects. However, although the improvement of computing power and algorithm improvement have further reduced the computing cost, there are still obstacles to the development of efficient methods to count and identify the structural properties of defects in large-scale disordered systems. Summary of the invention

[0004] The problem solved by the present invention is how to achieve statistics of large-scale disordered system architecture characteristics.

[0005] In order to solve the above problems, the present invention provides a method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process, comprising the following steps:

[0006] Step S1: constructing the interface structure of the single crystal silicon oxide layer using defect property simulation software according to the process parameters of the actual thermal oxidation process; identifying and deleting molecules in the voids of the interface structure and molecules in the vacuum layer;

[0007] Step S2: extracting an independent structure in the depth range of the interface structure to be counted, identifying and counting structural parameters in the independent structure, wherein the structural parameters include defect density and defect type.

[0008] Furthermore, in step S1, the interface structure of the single crystal silicon oxide layer is constructed using defect property simulation software, including:

[0009] Molecular dynamics is used to simulate the oxide layer growth process, defect property simulation software is used to construct a single crystal silicon substrate, a vacuum layer is set on the single crystal silicon substrate, and the interface structure of the single crystal silicon oxide layer is simulated and generated through a thermal oxidation process.

[0010] Furthermore, the particle size of the particles in the simulated oxide layer growth process ranges from 10 to 100 μm.

[0011] Furthermore, the thermal oxidation process includes a dry oxygen thermal oxidation process and / or a wet oxygen thermal oxidation process.

[0012] Furthermore, in step S2, the independent structure is cut out according to the depth range of the interface structure that needs to be counted, including:

[0013] The upper and lower boundaries of the intercepted independent structure are specified in the defect property simulation software, and after the upper and lower boundary data are input, the independent structure corresponding to the upper and lower boundary data is output.

[0014] Furthermore, in step S2, the structural parameters at least include bond length, bond angle, coordination number, atomic type and atomic number.

[0015] Furthermore, in step S2, the identifying and counting of structural parameters in the independent structure includes:

[0016] Step S21: Counting the bonding list of all atoms in the independent structure, including the atom type, interatomic distance and the coordination number;

[0017] Step S22: judging whether each atom belongs to a constituent atom of a specific defect type according to the bonding list, so as to determine the defect type and defect number in the independent structure;

[0018] Step S23: Obtain the defect density of a specific type in the independent structure by counting the total number of defects and the total number of atoms.

[0019] Further, in step S1, the defect property simulation software includes SpacEEsys.Def.

[0020] Furthermore, in step S2, after identifying and counting the structural parameters in the independent structure, the method further includes outputting the statistical results of the structural parameters in a graphical manner using drawing software.

[0021] Furthermore, the drawing software includes: Matplotlib.

[0022] The advantage of the method for generating the defect structure of a single crystal silicon oxide layer based on simulating an actual process described in the present invention over the prior art is that the interface structure of the single crystal silicon oxide layer is constructed by defect property simulation software to obtain the interface structure of a disordered system containing defects, the molecules in the voids of the interface structure and the molecules in the vacuum layer are identified and deleted, and the interfering molecules are removed, which is conducive to the accurate identification of later structural parameters; independent structures are intercepted according to the depth range of the interface structure that needs to be counted, and after the range that needs to be counted is accurately determined, the structural parameters in the independent structure are identified and counted, and the structural characteristics of the independent structure are grasped through the structural parameters, which is conducive to accurately grasping the important structural characteristics of the disordered system including defect density and defect type, and is of great significance for establishing the connection between microstructures such as defects and macro preparation processes or semiconductor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process in an embodiment of the present invention;

[0024] Figure 2 A flowchart of identifying and counting structural parameters in an independent structure in an embodiment of the present invention;

[0025] Figure 3 The SpacEEsys.Def software in the embodiment of the present invention removes the gas molecule setting window;

[0026] Figure 4 It is a setting window of the SpacEEsys.Def software for cutting out independent structures in the depth range of the interface structure to be counted in the embodiment of the present invention;

[0027] Figure 5 It is a structural schematic diagram of an independent structure cut out in an embodiment of the present invention;

[0028] Figure 6 is a statistical distribution diagram of defect types in an independent structure in an embodiment of the present invention;

[0029] Figure 7 is a statistical distribution diagram of bond lengths in an independent structure in an embodiment of the present invention;

[0030] Figure 8 It is a statistical distribution diagram of bond angles in an independent structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0032] It should be noted that in the description of the embodiments of the present application, the description of the term "some specific embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0033] The embodiment of the present invention provides a method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process, comprising the following steps:

[0034] Step S1: constructing the interface structure of the single crystal silicon oxide layer using defect property simulation software according to the process parameters of the actual thermal oxidation process; identifying and deleting molecules in the voids of the interface structure and molecules in the vacuum layer;

[0035] Step S2: extracting independent structures within the depth range of the interface structure to be counted, identifying and counting structural parameters in the independent structures, the structural parameters including defect density and defect type.

[0036] The method for generating the defect structure of a single crystal silicon oxide layer based on simulating an actual process described in the present invention constructs the interface structure of the single crystal silicon oxide layer through defect property simulation software, obtains the interface structure of a disordered system containing defects, identifies and deletes molecules in the voids of the interface structure and molecules in the vacuum layer, removes interfering molecules, and is conducive to the accurate identification of later structural parameters; extracts independent structures according to the depth range of the interface structure that needs to be counted, identifies and counts the structural parameters in the independent structure after accurately determining the range that needs to be counted, and grasps the structural features of the independent structure through the structural parameters, which is conducive to accurately grasping the important structural features of the disordered system including defect density and defect type, and is of great significance for establishing the connection between microstructures such as defects and macro preparation processes or semiconductor devices.

[0037] In some specific embodiments, in step S1, the interface structure of the single crystal silicon oxide layer is constructed using defect property simulation software, including:

[0038] Molecular dynamics is used to simulate the oxide layer growth process, defect property simulation software is used to construct a single crystal silicon substrate, a vacuum layer is set on the single crystal silicon substrate, and the interface structure of the single crystal silicon oxide layer is simulated and generated through a thermal oxidation process.

[0039] This embodiment simulates the actual oxide layer growth process to obtain the interface structure of the single crystal silicon oxide layer corresponding to the actual process. It has a short cycle, low cost and easy control of atomic level data, which makes up for the shortcomings of high detection cost, long preparation and analysis cycle, and test results that cannot directly reflect the structural conditions of defects in actual experiments.

[0040] In some specific embodiments, the particle size of the particles in the simulated oxide layer growth process ranges from 10 to 100 μm.

[0041] Therefore, in order to avoid the non-physical quantum confinement effect caused by finite scale, in this embodiment, when simulating the oxide layer growth process, the particle size range is set to be 2-4 orders of magnitude higher than the nanometer energy level calculated by quantum chemistry and first principles, so as to improve the accuracy and controllability of the simulation.

[0042] In some specific embodiments, the thermal oxidation process includes a dry oxygen thermal oxidation process and / or a wet oxygen thermal oxidation process.

[0043] In this embodiment, the specific process of the thermal oxidation process is not limited, and any process corresponding to the actual thermal oxidation process can be simulated and used, such as the above-mentioned dry oxygen thermal oxidation process or wet oxygen thermal oxidation process, or a process in which the dry oxygen thermal oxidation process and the wet oxygen thermal oxidation process alternately generate an oxide layer, and other types of thermal oxidation processes that can be simulated can also be used. Therefore, the simulation range of this embodiment is wide, and the structural features in the disordered system corresponding to various processes can be counted.

[0044] In some specific embodiments, in step S2, the independent structure is cut out according to the depth range of the interface structure to be counted, including:

[0045] In the defect property simulation software, the upper and lower boundaries of the intercepted independent structure are specified, and after the upper and lower boundary data are input, the independent structure corresponding to the upper and lower boundary data is output. The independent structure described in this embodiment is intercepted by manual input, the setting method is flexible, the structure size is clear, and it is conducive to the accuracy of statistics.

[0046] In some specific embodiments, in step S2, the structural parameters at least include bond length, bond angle, coordination number, atomic type and atomic number. Thus, mastering the various structural parameters in the independent structure is more conducive to accurately mastering the structural characteristics in the large-scale system corresponding to the independent structure.

[0047] In some specific embodiments, in step S2, identifying and counting structural parameters in the independent structure includes:

[0048] Step S21: Count the bonding lists of all atoms in the independent structure, including atom types, interatomic distances, and coordination numbers;

[0049] Step S22: judging whether each atom belongs to a constituent atom of a specific defect type according to the bonding list, so as to determine the defect type and defect number in the independent structure;

[0050] Step S23: Obtain the density of a specific type of defects in the independent structure by counting the total number of defects and the total number of atoms.

[0051] In this embodiment, through the spatial bonding tracking analysis technology, the atomic data in the independent structure are statistically analyzed to present a bonding list, including the total number and type of atoms, the distance between atoms or bond length, the coordination number, etc., and then the defect data are obtained through the atomic data corresponding to the defects, including the defect type, the number of defects of various defects and the defect density, etc., thereby achieving accurate grasp of the main structural features in the independent structure under the premise of disordered structural features.

[0052] In some specific embodiments, in step S1, the defect property simulation software includes SpacEEsys.Def.

[0053] In some specific embodiments, after identifying and counting the structural parameters of the independent structure in step S2, the statistical results of the structural parameters are outputted in a graphical manner using drawing software, thereby realizing visualization of the structural data, which is convenient and intuitive.

[0054] In some specific embodiments, the drawing software includes Matplotlib.

[0055] In some specific embodiments, hydrogen atoms are added to the edge of the intercepted independent structure, thereby making the independent structure more saturated, which is beneficial to the subsequent calculation of properties such as state density.

[0056] Example 1

[0057] This embodiment implements statistics of structural features in independent structures based on a method for generating defect structures of single crystal silicon oxide layers by simulating actual processes, including the following contents:

[0058] The interface structure of the single-crystal silicon oxide layer was simulated using software: the interaction between atoms was described by a reaction force field, and a dry oxygen thermal oxidation process was used to simulate the dry oxygen thermal oxidation process of a constructed 2.2nm×2.2nm×4.4nm single-crystal silicon substrate (a total of 1024 Si atoms). A vacuum layer with a thickness of 1.5nm was added to the single-crystal silicon substrate, and the reaction temperature was controlled at 1433K. Finally, the interface structure of the oxide layer was obtained. The cross-sectional structure configuration is shown in the figure. Figure 5As shown, the thickness of the obtained oxide layer is 1.7nm. When identifying and deleting molecules in the interface structure voids and molecules in the vacuum layer, the height coordinate of the oxide layer is selected as 58.0nm, and the independent structure is intercepted within the depth range of the interface structure. When intercepting, the upper boundary is selected as 42.0nm and the lower boundary position is 57.4nm. The structural parameters in the independent structure are identified and counted, and the defect density obtained by statistics is 2.1079g / cm 3 , the silicon-oxygen number ratio is 0.7926. Specifically, the defect type and defect density are as follows Figure 6 The distribution data of bond length and bond angle are shown in Figure 7 and Figure 8 shown.

[0059] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for generating a defect structure of a single crystal silicon oxide layer based on a simulation of an actual process, characterized in that: The steps include: Step S1: constructing an interface structure of a single crystal silicon oxide layer according to process parameters of an actual thermal oxidation process; identifying and deleting molecules in the voids of the interface structure and molecules in the vacuum layer; Step S2: extracting an independent structure in the depth range of the interface structure to be counted, identifying and counting structural parameters in the independent structure, wherein the structural parameters include defect density and defect type; Wherein, in step S2, the identifying and counting of structural parameters in the independent structure further includes: Step S21: Counting the bonding list of all atoms in the independent structure, including the atom type, interatomic distance and the coordination number; Step S22: judging whether each atom belongs to a constituent atom of a specific defect type according to the bonding list, so as to determine the defect type and defect number in the independent structure.

2. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 1, characterized in that: In step S1, the process of constructing the interface structure of the single crystal silicon oxide layer includes: Molecular dynamics is used to simulate the oxide layer growth process, defect property simulation software is used to construct a single crystal silicon substrate, a vacuum layer is set on the single crystal silicon substrate, and the interface structure of the single crystal silicon oxide layer is simulated and generated through a thermal oxidation process.

3. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 2, characterized in that: The particle size of the particles in the simulated oxide layer growth process ranges from 10 to 100 μm.

4. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 2, characterized in that: The thermal oxidation process includes a dry oxygen thermal oxidation process and / or a wet oxygen thermal oxidation process.

5. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 1, characterized in that: In step S2, the independent structure is cut out according to the depth range of the interface structure that needs to be counted, including: The upper and lower boundaries of the intercepted independent structure are specified in the defect property simulation software, and after the upper and lower boundary data are input, the independent structure corresponding to the upper and lower boundary data is output.

6. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 1, characterized in that: In step S2, the structural parameters at least include bond length, bond angle, coordination number, atomic type and atomic number.

7. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 6, characterized in that: In step S2, the identifying and counting of structural parameters in the independent structure further includes: Step S23: Obtain the defect density of a specific type in the independent structure by counting the total number of defects and the total number of atoms.

8. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 2, characterized in that: The defect property simulation software includes SpacEEsys.Def.

9. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 1, characterized in that: In step S2, after identifying and counting the structural parameters in the independent structure, the method further includes outputting the statistical results of the structural parameters in a graphical manner using drawing software.

10. The method for generating a defect structure of a single crystal silicon oxide layer based on simulating an actual process according to claim 9, characterized in that: The drawing software includes: Matplotlib.

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