A gallium diffusion apparatus

Abstract

The utility model discloses a gallium diffusion device, including diffusion furnace and setting in diffusion furnace's multiple groups quartz tube, be equipped with nitrogen gas pipeline on the quartz tube, be equipped with quartz cage boat in the quartz tube, and be equipped with a plurality of openings on the quartz cage boat, the quartz cage boat is placed and is equipped with the quartz boat of silicon wafer, still be equipped with the crucible of built -in solid gallium oxide in the quartz cage boat, the quartz cage boat is equipped with hydrogen pipeline one end of crucible reduction oxide gallium into gaseous gallium atom and diffuses on the silicon wafer. The utility model will be equipped with the crucible of solid gallium oxide in the quartz cage boat, and through the hydrogen gas that is passed in the upper reduction into gallium through the surface of gallium oxide, at this moment, gallium forms the gaseous state, and realizes gallium diffusion by blowing to the silicon wafer on one side through the hydrogen gas flow. Therefore, can improve the efficiency and the evenness of gallium diffusion, and reduced the use cost of gallium.

Description

Technical Field

[0001] This utility model belongs to the field of diode processing technology, specifically relating to a gallium diffusion device. Background Technology

[0002] The core purpose of diffusing gallium on silicon wafers is to achieve precise and controllable P-type doping, especially in advanced semiconductor manufacturing, where it can replace traditional boron doping to form ultra-shallow junctions. Silicon is a tetravalent element, while trivalent gallium atoms, upon entering the silicon lattice, generate conductive holes due to insufficient valence electrons, thus transforming silicon into a P-type semiconductor where holes are the majority carriers. Compared to boron, gallium's key advantage lies in its extremely low diffusion coefficient: during subsequent high-temperature processes (such as annealing), gallium atoms diffuse extremely slowly, effectively suppressing junction depth increases and ensuring a steep and precise doping profile, which is crucial for nanoscale transistors. Furthermore, gallium significantly suppresses transient enhanced diffusion (TED) (the abnormally rapid diffusion of boron caused by implantation damage), and its heavier atomic mass also reduces the channeling effect during ion implantation, resulting in a more surface-close and uniform doping distribution. Simultaneously, gallium has higher solid solubility in silicon, allowing for higher hole concentrations to reduce contact resistance. Therefore, in the fabrication of PMOS transistor source / drain regions at advanced technology nodes of 45nm and below, diffused gallium has become a key process for achieving the required ultra-shallow junctions (junction depth <20nm), precisely controlling electrical characteristics, and overcoming short-channel effects, thus meeting the stringent requirements of modern high-performance chips for device miniaturization and electrical performance.

[0003] In conventional diffusion furnaces, the crucible is located inside a quartz tube outside a quartz cage boat, and the quartz cage boat has openings. Metal atoms are blown into the silicon wafer inside the quartz cage boat by gas to achieve diffusion. However, due to the high cost of gallium and the fact that the atoms are blown in from outside the quartz cage boat, the diffusion cost is high and the diffusion is uneven. Utility Model Content

[0004] To address the aforementioned shortcomings of existing technologies, a gallium diffusion device is provided, which solves the problems of uneven gallium diffusion and high cost in existing technologies.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A gallium diffusion device includes a diffusion furnace and multiple sets of quartz tubes disposed within the diffusion furnace. Nitrogen gas pipes are provided on the quartz tubes, and quartz cage boats are disposed inside the quartz tubes. The quartz cage boats have several openings. A quartz boat containing a silicon wafer is placed inside the quartz cage boats. A crucible containing solid gallium oxide is also disposed inside the quartz cage boats. A hydrogen gas pipe is provided at one end of the crucible in the quartz cage boats to reduce the gallium oxide into gaseous gallium atoms and diffuse them onto the silicon wafer.

[0007] The above structural design involves placing a crucible containing solid gallium oxide inside a quartz cage. Hydrogen gas is then introduced from above, reducing the gallium oxide surface to gallium, which is then in a gaseous state. This gallium is diffused onto a silicon wafer on one side by the hydrogen gas flow. Simultaneously, nitrogen gas is introduced through the quartz tube to prevent the reduced gallium from oxidizing. Therefore, this design improves the efficiency and uniformity of gallium diffusion, while reducing the cost of using gallium.

[0008] Preferably, the crucible is movably disposed inside the quartz cage boat and located on one side of the quartz boat, and the crucible is open.

[0009] With the above structural design, the crucible is open, which increases the contact with the introduced hydrogen gas, thereby improving the reduction efficiency of gallium oxide and enabling the reduced gallium to diffuse, thus improving the diffusion efficiency.

[0010] Preferably, the quartz cage boat includes a body with the opening provided on it. The body is connected by an upper part and a lower part, and is hinged at one side of the connection. The two ends of the body are also provided with snap-on end caps.

[0011] With the above structural design, the quartz cage boat can be put into and taken out by opening the end, or the main body can be opened after opening the end cover for more convenient quartz cage boat putting into and taking out.

[0012] Preferably, the end cap has an installation hole for installing a hydrogen pipeline, and the end of the hydrogen pipeline has a diversion outlet inside the quartz cage boat.

[0013] Preferably, the gas outlet is higher than the crucible.

[0014] Preferably, the diverting outlet includes a horn-shaped outlet, and the outlet is provided with a downwardly curved arc-shaped baffle to separate the interior of the outlet into an upper outlet and a lower outlet.

[0015] With the above structural design, the upper outlet, formed by a downward-curving arc-shaped baffle in the middle of the gas splitter head, forms a funnel shape that can blow the reduced gaseous gallium into the silicon wafer and increase the airflow width, thereby increasing the uniformity of gallium diffusion; the lower outlet can introduce more hydrogen into the crucible to reduce gallium oxide, increase the amount of reduced gaseous gallium, and thus improve the diffusion efficiency.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Compared to the existing design where the crucible is placed outside the quartz cage, this invention places the crucible containing solid gallium oxide inside the quartz cage. Hydrogen gas is then introduced from above, reducing the gallium oxide surface to gallium, which is then in a gaseous state. The gaseous gas then diffuses the gallium onto a silicon wafer on one side. Therefore, this improves the efficiency and uniformity of gallium diffusion and reduces the cost of using gallium.

[0018] 2. The present invention features a downward-curving arc-shaped baffle in the middle of the gas diversion head, which isolates the gas diversion head into an upper gas outlet that forms a funnel shape. This allows the reduced gaseous gallium to be blown into the silicon wafer location, and also increases the airflow width, thereby increasing the uniformity and efficiency of gallium diffusion. The lower gas outlet can introduce more hydrogen into the crucible to reduce gallium oxide, increasing the amount of reduced gaseous gallium and thus improving diffusion efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0021] Figure 3 yes Figure 1 Schematic diagram of the structure of a quartz cage boat;

[0022] Figure 4 yes Figure 2 A schematic diagram of the structure of the gas outlet in the middle.

[0023] In the picture:

[0024] 1. Diffusion furnace; 2. Quartz tube; 3. Quartz cage boat; 4. Opening 3a; 5. Body 3b; 6. Upper part 31b; 7. Lower part 32b; 8. End cap 3c; 9. Mounting hole 31c; 10. Quartz boat; 11. Crucible; 12. Hydrogen pipeline; 13. Diverter head 6a; 14. Outlet 61a; 15. Upper outlet 611a; 16. Lower outlet 612a; 17. Arc-shaped baffle 62a; 18. Nitrogen pipeline. Detailed Implementation

[0025] To explain in detail the technical content, structural features, objectives and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0026] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] Please see Figures 1 to 3 A gallium diffusion device includes a diffusion furnace 1 and multiple sets of quartz tubes 2 disposed within the diffusion furnace 1. Each quartz tube 2 has a nitrogen gas pipe 7 for introducing nitrogen gas to prevent the reduced gallium from being re-oxidized. A quartz cage boat 3 is disposed within each quartz tube 2, and the quartz cage boat 3 has several openings 3a. A quartz boat 4 containing a silicon wafer is placed inside the quartz cage boat 3, and a crucible 5 containing solid gallium oxide is also disposed inside the quartz cage boat 3. A hydrogen gas pipe 6 is provided at one end of the crucible 5 to reduce the gallium oxide into gaseous gallium atoms, which then diffuse onto the silicon wafer. In this embodiment, the diffusion furnace 1, the internal quartz tubes 2, and other components not mentioned in this application are all prior art and therefore will not be described in detail here.

[0028] Please continue reading. Figure 2 Furthermore, the crucible 5 is movably disposed within the quartz cage 3 and located on one side of the quartz boat 4, with the crucible 5 being open. The built-in design of the crucible 5 is more cost-effective and improves diffusion efficiency compared to the existing method of diffusion from the outside of the quartz cage 3. Simultaneously, the open design of the crucible 5 increases the contact between the solid gallium oxide and hydrogen gas within the crucible 5, reducing the gallium oxide to gaseous gallium, thereby improving gallium diffusion efficiency.

[0029] Please see Figure 3The quartz cage boat 3 includes a body 3b with an opening 3a. The body 3b is connected by an upper part 31b and a lower part 32b, and is hinged at one side of the connection. Both ends of the body 3b are provided with snap-on end caps 3c. The end caps 3c have mounting holes 31c for installing hydrogen pipes 6, and the end of the hydrogen pipes 6 is provided with a gas outlet 6a inside the quartz cage boat 3. When it is necessary to remove or place the quartz boat 4 inside the quartz cage boat 3, two methods can be used as needed: one end cap 3c can be opened for removal or placement; if this method is inconvenient, the upper part 31b of the body 3b can be opened after opening the end cap 3c to remove or place the quartz boat 4.

[0030] In this embodiment, the gas outlet 6a is higher than the crucible 5, which facilitates the formation of an airflow to blow the reduced gaseous gallium into the silicon wafer area.

[0031] Please see Figure 4 Furthermore, the gas outlet 6a includes a trumpet-shaped outlet 61a, and the outlet 61a is provided with a downwardly curved arc-shaped baffle 62a that isolates the interior of the outlet 61a into an upper outlet 611a and a lower outlet 612a. The upper outlet 611a, after isolation, forms a trumpet-shaped structure, allowing for a wider dispersion area of ​​the blown hydrogen gas and a more uniform distribution when the airflow carries the gaseous gallium, thus resulting in more uniform diffusion of gallium on the silicon wafer. Simultaneously, the lower outlet 612a, through the arc-shaped baffle 62a, introduces hydrogen gas downwards into the crucible 5, ensuring sufficient contact between the solid gallium oxide and the hydrogen gas, and reducing more gaseous gallium.

[0032] The working principle of this utility model is as follows:

[0033] When gallium diffusion is required on silicon wafers, firstly, the temperature of the diffusion furnace 1 is controlled, and the quartz boat 4 containing the silicon wafer is placed inside the quartz cage boat 3. Initially, the crucible 5 contains fixed gallium oxide. Hydrogen gas is introduced through the hydrogen pipe 6, and the hydrogen gas discharged from the lower outlet 612a is blown onto the surface of the gallium oxide, reducing it to gaseous gallium. Simultaneously, the hydrogen gas blown from the upper outlet 611a forms an airflow that carries the gaseous gallium to the silicon wafer, where it adheres and completes the gallium diffusion. Therefore, this application uses an internal crucible 5 to directly deliver gaseous gallium onto adjacent silicon wafers for diffusion, saving on gallium usage costs while achieving more uniform and efficient diffusion.

[0034] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A gallium diffusion device, characterized in that, The device includes a diffusion furnace (1) and multiple sets of quartz tubes (2) disposed within the diffusion furnace (1). Nitrogen pipes (7) are provided on the quartz tubes (2). Quartz cages (3) are provided inside the quartz tubes (2), and several openings (3a) are provided on the quartz cages (3). Quartz boats (4) containing silicon wafers are placed inside the quartz cages (3). Crucibles (5) containing solid gallium oxide are also provided inside the quartz cages (3). A hydrogen pipe (6) is provided at one end of the crucible (5) of the quartz cages (3) to reduce gallium oxide into gaseous gallium atoms and diffuse them onto the silicon wafers.

2. The gallium diffusion device as described in claim 1, characterized in that, The crucible (5) is movably disposed inside the quartz cage boat (3) and located on one side of the quartz boat (4), and the crucible (5) is open.

3. The gallium diffusion device as described in claim 1, characterized in that, The quartz cage boat (3) includes a body (3b), the opening (3a) is provided on the body (3b), the body (3b) is connected by an upper part (31b) and a lower part (32b) and is hinged at one side of the connection, and the two ends of the body (3b) are also provided with snap-on end caps (3c).

4. A gallium diffusion device as described in claim 3, characterized in that, The end cap (3c) is provided with an installation hole (31c) for installing a hydrogen pipeline (6), and the end of the hydrogen pipeline (6) is provided with a gas outlet (6a) inside the quartz cage (3).

5. A gallium diffusion device as described in claim 4, characterized in that, The gas outlet (6a) is higher than the crucible (5).

6. A gallium diffusion device as described in claim 4, characterized in that, The split outlet (6a) includes a horn-shaped outlet (61a), and the outlet (61a) is provided with a downwardly curved arc-shaped baffle (62a) that separates the interior of the outlet (61a) into an upper outlet (611a) and a lower outlet (612a).

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