Capacitor having a curling iron shape structure and method of manufacturing the same
By alternately stacking highly doped and low doped polysilicon layers on a substrate to form a hairpin-shaped capacitor with axial ribs and a cylindrical body, the problem of large area occupied by existing capacitors is solved, achieving high capacity and high integration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING SUPERSTRING ACAD OF MEMORY TECH
- Filing Date
- 2021-11-29
- Publication Date
- 2026-05-29
AI Technical Summary
Existing capacitors with a curling iron-shaped structure occupy a large substrate area and have low integration density.
A capacitor with an upright, curling iron-shaped structure is formed by alternating layers of highly doped and low-doped polysilicon on a substrate, forming polysilicon pillars and carbon pillars through etching, and then combining an insulating layer and a pillar sleeve.
This increases the capacitance of the capacitor, reduces the substrate area it occupies, and improves the integration density.
Smart Images
Figure CN116209347B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor devices and their manufacturing technology, and in particular to a capacitor with a curling iron-shaped structure and its manufacturing method. Background Technology
[0002] In capacitor manufacturing, to increase capacitance, one design incorporates electrodes with comb-like teeth, creating a capacitor with a curling iron-like structure. For example, the semiconductor capacitor structure and its fabrication method disclosed in patent application number 201910156374.5, with its curling iron-shaped structure, increases the electrode area due to the presence of the comb teeth, thereby improving capacitance.
[0003] However, existing capacitors with a curling iron-shaped structure either use the back of the comb (i.e., the skeleton) to stand the comb teeth upright against the substrate, or both the back of the comb (i.e., the skeleton) and the comb teeth are against the substrate. These types of capacitors with a curling iron-shaped structure occupy a large substrate area and have low integration. Summary of the Invention
[0004] To solve the above-mentioned technical problems, the present invention provides a capacitor with a hair curler-shaped structure, including an upper plate, a lower plate and an insulating layer;
[0005] The lower electrode plate includes a first frame and multiple layered electrode plates. The first frame is vertically fixed on the substrate and has multiple axial ribs spaced circumferentially, which are in the shape of a curling iron. The layered electrode plates are arranged at different heights from the substrate along the first frame upwards. The center of the layered electrode plates is aligned with the axis of the first frame and the two are fixedly connected.
[0006] The upper electrode plate includes a cylindrical sleeve and multiple inner ribs. The cylindrical sleeve is shaped like a cylindrical cover and covers the lower electrode plate. The inner ribs are spaced apart in the gaps between the electrode plates and are fixedly connected to the inner sidewall of the cylindrical sleeve.
[0007] The insulating layer is filled between the upper and lower electrode plates to insulate and isolate them.
[0008] Optionally, the lower electrode plate has a doping concentration of not less than 10. 20 pcs / cm 3 Polycrystalline silicon material.
[0009] Optionally, the upper electrode plate is made of titanium nitride.
[0010] The present invention also provides a method for manufacturing a capacitor having a curling iron-shaped structure, comprising the following steps:
[0011] S10 has multiple highly doped polysilicon layers and low doped polysilicon layers alternately stacked on the substrate;
[0012] S20 is designed based on the image layout of a capacitor with a curling iron-shaped structure. A mask is set on the upper end of the polysilicon layer for the first etching to form a polysilicon pillar.
[0013] S30 is arranged with multiple carbon pillars circumferentially spaced around the edge of the polysilicon pillar, and each carbon pillar covers a portion of the polysilicon pillar.
[0014] S40 injects dopants into polysilicon pillars through the gaps between multiple carbon pillars, unifying the polysilicon layers exposed between the carbon pillars into highly doped polysilicon, forming a first skeleton with multiple axial ribs.
[0015] S50 removes carbon pillars; the selectivity is determined according to the different doping concentrations of the polysilicon pillars, and a second etching is performed to remove the low-doped polysilicon, while the remaining high-doped polysilicon layer forms the layer electrode and the first bob-shaped skeleton forms the lower electrode.
[0016] S60 uses a deposition process to form the insulating layer;
[0017] The S70 uses a deposition process to form an upper electrode plate with inner ribs and a cylindrical sleeve-shaped body that wraps around the lower electrode plate outside the insulation layer.
[0018] Optionally, the doping concentration of the highly doped polycrystalline silicon layer is not less than 10. 20 pcs / cm 3 .
[0019] Optionally, the doping concentration of the low-doped polycrystalline silicon layer is 0-10. 16 pcs / cm 3 .
[0020] Optionally, in step S10, the thickness of the low-doped polysilicon layer is equal to the sum of the thickness of the inner rib and twice the thickness of the insulating layer; the thickness of the high-doped polysilicon layer is equal to the thickness of the layer plate.
[0021] Optionally, in step S30, the carbon column is formed in the following manner:
[0022] First, carbon is filled into a substrate containing polycrystalline silicon pillars to bury the polycrystalline silicon pillars;
[0023] Secondly, multiple photoresist layers are circumferentially spaced around the edge of the polysilicon pillar;
[0024] Finally, carbon etching is performed to form carbon pillars under the photoresist layer.
[0025] Optionally, in step S20, the cross-section of the polysilicon pillar is square or circular; in step S30, the cross-section of the carbon pillar is square or circular; if the cross-section of the polysilicon pillar is square, carbon pillars are set at the four corners of the square; if the cross-section of the polysilicon pillar is circular, multiple carbon pillars are evenly spaced around the edge of the polysilicon pillar.
[0026] Optionally, in step S70, the upper electrode plate outside the insulating layer is formed using a titanium nitride deposition process.
[0027] The present invention relates to a capacitor with a curling iron-shaped structure and a method for manufacturing the same. During manufacturing, multiple highly doped polysilicon layers and low-doped polysilicon layers are alternately stacked on a substrate. Specifically, after depositing one highly doped polysilicon layer, a low-doped polysilicon layer is deposited, followed by another highly doped polysilicon layer, and so on, forming multiple spaced low-doped and highly doped polysilicon layers. A mask is set according to a pattern design, and a first etching is performed to form polysilicon pillars. Multiple carbon pillars are circumferentially spaced around the edges of the polysilicon pillars. Dopant is injected into the polysilicon pillars through the gaps between the carbon pillars, forming a highly doped first framework with multiple axial ribs on the exposed polysilicon pillars. The carbon pillars are removed; the selectivity is determined according to the different doping concentrations of the polysilicon pillars, and a second etching is performed. The remaining highly doped polysilicon layer forms the layer electrode plate, and the first bob-shaped framework forms the lower electrode plate; the axial ribs improve the strength and stability of the polysilicon pillars and the first framework; an insulating layer is formed using a deposition process; a bob-shaped sleeve with inner ribs is formed outside the insulating layer using a deposition process, and the bob-shaped sleeve covers the lower electrode plate; the above method is used to fabricate an upright capacitor with a bob-shaped structure, which stands upright on the substrate. The layer electrode plates, axial ribs, and inner ribs increase the area of the two electrodes, increase the capacitance, reduce the substrate area occupied, and improve the integration density.
[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.
[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:
[0031] Figure 1 This is a schematic diagram of a cross-section of a capacitor with a curling iron-shaped structure according to an embodiment of the present invention;
[0032] Figure 2 This is a flowchart illustrating a method for manufacturing a capacitor with a curling iron-shaped structure according to an embodiment of the present invention.
[0033] Figure 3 This is a cross-sectional schematic diagram of a capacitor with a curling iron-shaped structure, which is an embodiment of the manufacturing method of the present invention, after multiple highly doped polysilicon layers and low-doped polysilicon layers are alternately stacked on a substrate.
[0034] Figure 4 This is a cross-sectional schematic diagram of a capacitor with a curling iron-shaped structure manufactured according to the present invention, after the first etching of multiple alternating layers of highly doped polysilicon and low doped polysilicon on a substrate to form a polysilicon pillar in an embodiment of the manufacturing method of the present invention.
[0035] Figure 5 This is a cross-sectional schematic diagram of a capacitor with a hairpin-shaped structure manufactured according to the present invention, after forming carbon pillars around a polycrystalline silicon pillar and implanting dopants.
[0036] Figure 6 for Figure 5 A top view of an embodiment where both the polycrystalline silicon pillar and the carbon pillar have circular cross-sections;
[0037] Figure 7 for Figure 5 A top view of an embodiment where both the polycrystalline silicon pillar and the carbon pillar have square cross-sections;
[0038] Figure 8 This is a cross-sectional schematic diagram of the manufacturing method of the capacitor with a curling iron-shaped structure of the present invention after removing the carbon pillars around the polycrystalline silicon pillars in an embodiment.
[0039] Figure 9 for Figure 8 Schematic diagram of section AA in the diagram;
[0040] Figure 10 This is a cross-sectional schematic diagram of the capacitor with a curling iron-shaped structure after the second etching and setting of the insulating layer in an embodiment of the manufacturing method of the present invention;
[0041] Figure 11 This is a schematic diagram showing the cross-sectional effect of the upper and lower electrode structures with the upper electrode having the shape of a curling iron and the removal of the insulating layer, based on the graphical design of the capacitor of the present invention. Detailed Implementation
[0042] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0043] like Figure 1As shown, an embodiment of the present invention provides a capacitor with a curling iron-shaped structure, including an upper electrode plate 1, a lower electrode plate 2, and an insulating layer 3;
[0044] The lower electrode plate 2 includes a first frame 22 and multiple layered electrode plates 21. The first frame 22 is vertically fixed on the substrate 4 and has multiple axial ribs 23 arranged circumferentially at intervals, which are in the shape of a curling iron. The layered electrode plates 21 are arranged from the substrate 4 upward along the first frame 22 at different heights from the substrate 4. The center of the layered electrode plate 21 is aligned with the axis of the first frame 22 and the two are fixedly connected.
[0045] The upper electrode plate 1 includes a cylindrical sleeve and a plurality of inner rib plates 11. The cylindrical sleeve is shaped like a cylindrical cover and covers the lower electrode plate 2. The inner rib plates 11 are spaced apart in the gaps of the layer electrode plates 21 and are fixedly connected to the inner sidewall of the cylindrical sleeve.
[0046] The insulating layer 3 is filled between the upper electrode plate 1 and the lower electrode plate 2 to insulate and isolate them.
[0047] The working principle and beneficial effects of the above technical solution are as follows: The capacitor with a hairpin-shaped structure has a first frame and multiple layered plates on the lower electrode plate. The first frame has multiple axial ribs and is shaped like a hairpin. The axial ribs improve the strength and stability of the polysilicon pillar and the first frame. The upper electrode plate has an inner rib and a pillar-shaped sleeve body that covers the upper electrode plate. The inner ribs are spaced apart in the gaps between the layered plates and are fixedly connected to the inner sidewall of the pillar body. The upper electrode plate and the lower electrode plate are isolated by an insulating layer to form the two poles of the capacitor. The capacitor with the hairpin-shaped structure stands upright on the substrate. Each layered plate, axial rib, and inner rib increases the area of the two poles, increases the capacitance, reduces the area occupied on the substrate, and improves the integration.
[0048] In one embodiment, the lower electrode plate has a doping concentration of not less than 10. 20 pcs / cm 3 The material is polycrystalline silicon; the upper electrode plate is made of titanium nitride.
[0049] The working principle and beneficial effects of the above technical solution are as follows: This solution limits the lower limit of the conductive ion doping concentration of the lower electrode plate to determine the conductivity of the polycrystalline silicon material of the lower electrode plate of the capacitor and to meet the performance requirements of the capacitor; similarly, limiting the upper electrode plate to use titanium nitride material is also to ensure the conductivity of the upper electrode plate of the capacitor and to meet the performance requirements of the capacitor.
[0050] like Figure 1-10 As shown, this embodiment of the invention provides a method for manufacturing a capacitor with a curling iron-shaped structure, such as... Figure 2 As shown, it includes the following steps:
[0051] S10 Figure 3 As shown, multiple highly doped polysilicon layers and low-doped polysilicon layers are alternately stacked on the substrate 4, namely, low-doped polysilicon layer 5 and highly doped polysilicon layer 6.
[0052] S20 Figure 4 As shown, based on the image layout design of a capacitor with a curling iron-shaped structure, a mask is set on the upper end of the polysilicon layer for the first etching to form a polysilicon pillar 9.
[0053] S30 Figure 5-7 As shown, multiple carbon pillars 7 are arranged circumferentially around the edge of the polysilicon pillar 9, and each carbon pillar 7 covers a portion of the polysilicon pillar 9.
[0054] S40 Figure 5-7 As shown, dopants are injected into the polysilicon pillars 9 through the gaps between multiple carbon pillars 7, unifying the polysilicon layers exposed between the carbon pillars 7 into highly doped polysilicon, such as... Figure 8-9 As shown, a first skeleton 22 with multiple axial ribs 23 is formed;
[0055] S50 Figure 8-9 As shown, carbon pillar 7 is removed; the selectivity is determined according to the different doping concentrations of the polysilicon pillars, and a second etching is performed to remove the low-doped polysilicon, and the remaining high-doped polysilicon layer forms the layer electrode 21 and the first skeleton 22 in the shape of a hairpin to form the lower electrode 2.
[0056] S60 Figure 10 As shown, the insulating layer 3 is formed using a deposition process;
[0057] S70 Figure 1 As shown, an upper electrode plate 1 with an inner rib plate 11 and a columnar sleeve body in the shape of a columnar sleeve are formed on the outside of the insulating layer 3 by a deposition process, which wraps the lower electrode plate 2.
[0058] The working principle and beneficial effects of the above technical solution are as follows: During manufacturing, multiple highly doped polysilicon layers and low-doped polysilicon layers are alternately stacked on the substrate. That is, after setting a layer of highly doped polysilicon, a layer of low-doped polysilicon is set, and then another layer of highly doped polysilicon is set, and so on, forming multiple spaced low-doped polysilicon layers and highly doped polysilicon layers. A mask is set according to the pattern design, and the first etching is performed to form polysilicon pillars. Multiple carbon pillars are circumferentially spaced around the edges of the polysilicon pillars. Dopant is injected into the polysilicon pillars through the gaps between the carbon pillars, and the polysilicon pillars exposed between the carbon pillars form a highly doped first framework with multiple axial ribs. The carbon pillars are removed; the selectivity is determined according to the different doping concentrations of the polysilicon pillars, and a second etching is performed. The remaining highly doped polysilicon layer forms the layer electrode plate, and the first bob-shaped framework forms the lower electrode plate; the axial ribs improve the strength and stability of the polysilicon pillars and the first framework; an insulating layer is formed using a deposition process; a bob-shaped sleeve with inner ribs is formed outside the insulating layer using a deposition process, and the bob-shaped sleeve covers the lower electrode plate; the above method is used to fabricate an upright capacitor with a bob-shaped structure, which stands upright on the substrate. The layer electrode plates, axial ribs, and inner ribs increase the area of the two electrodes, increase the capacitance, reduce the substrate area occupied, and improve the integration density.
[0059] In one embodiment, in step S10, the doping concentration of the highly doped polysilicon layer is not less than 10. 20 pcs / cm 3 The doping concentration of the low-doped polycrystalline silicon layer is 0-10. 16 pcs / cm 3 .
[0060] The working principle and beneficial effects of the above technical solution are as follows: This solution controls the conductive ion doping concentration of the highly doped polysilicon layer forming the lower electrode plate to be no less than its lower limit value during the process, so as to ensure the conductivity of the polysilicon material of the lower electrode plate of the capacitor and meet the performance requirements of the capacitor; by limiting the doping concentration of the low-doped polysilicon layer, the process selection ratio of the doping concentration of the high-doped polysilicon layer and the low-doped polysilicon layer is ensured, which makes it easy to remove the low-doped polysilicon layer in the second etching without damaging the high-doped polysilicon layer, thus ensuring process quality and product quality.
[0061] In one embodiment, in step S10, the thickness of the low-doped polysilicon layer is equal to the sum of the thickness of the inner rib and twice the thickness of the insulating layer; the thickness of the high-doped polysilicon layer is equal to the thickness of the layer plate.
[0062] The working principle and beneficial effects of the above technical solution are as follows: This solution defines the relationship between the thickness of the low-doped polycrystalline silicon layer and the thickness of the inner rib plate and the insulation layer, as well as the relationship between the thickness of the high-doped polycrystalline silicon layer and the thickness of the platen, which facilitates the determination of the thickness of the low-doped polycrystalline silicon layer and the high-doped polycrystalline silicon layer according to the capacitor design in the process, ensuring the processing accuracy, enhancing the consistency of process quality, and improving the yield.
[0063] In one embodiment, such as Figure 5-7 As shown, in step S30, the carbon column is formed in the following manner:
[0064] First, carbon is filled into the substrate 4 with polysilicon pillars 9 to bury the polysilicon pillars 9;
[0065] Secondly, multiple photoresist layers 8 are circumferentially spaced around the edge of the polysilicon pillar 9;
[0066] Finally, carbon etching is performed to form carbon pillars 7 under the photoresist layer 8.
[0067] The working principle and beneficial effects of the above technical solution are as follows: This solution provides a carbon pillar formation method, which adopts carbon filling and carbon etching. The carbon pillar is formed by leaving the carbon underneath the photoresist (PR) layer during carbon etching. The photoresist layer is removed simultaneously with the carbon pillar in step S50. This method is simple, easy to operate, easy to implement, and low in cost.
[0068] In one embodiment, such as Figure 5-7 As shown, in step S20, the cross-section of the polycrystalline silicon pillar is square or circular; in step S30, as... Figure 5-7 As shown, the cross-section of the carbon column 7 is square or circular; as Figure 5 and 7 As shown, if the cross-section of the polycrystalline silicon pillar 9 is square, then carbon pillars are placed at the four corners of the square; as... Figure 5 and 6 As shown, if the cross-section of the polysilicon pillar 9 is circular, then multiple pillars are evenly spaced around the edge of the polysilicon pillar in the circumferential direction. Figure 6 The image shows three circular carbon pillars.
[0069] The working principle and beneficial effects of the above technical solution are as follows: In this solution, the cross-sections of the polycrystalline silicon pillars and carbon pillars can be square or circular, that is, both can be square, or both can be circular, or one of the polycrystalline silicon pillars and the other can be square and the other circular; multiple carbon pillars can be evenly spaced around the edge of the polycrystalline silicon pillar, and the gaps between the carbon pillars are the same cross-sectional shape of the first skeleton formed subsequently; the adjacent gaps between three carbon pillars form axial ribs, that is, three carbon pillars will form three axial ribs, and four carbon pillars will form four axial ribs. The number of carbon pillars should not be too large, as too many pillars will divide the edge of the polycrystalline silicon pillar too finely, and too many axial ribs will result in a small inner rib area of the upper electrode plate, which is not conducive to increasing the electrode plate area. Therefore, it is better to set three to four.
[0070] In one embodiment, in step S70, the upper electrode plate outside the insulating layer is formed using a titanium nitride deposition process.
[0071] The working principle and beneficial effects of the above technical solution are as follows: This solution uses a titanium nitride deposition process, which can ensure the uniformity and consistency of the thickness of the upper electrode plate. Moreover, the shape of the exposed part of the deposition base (substrate and lower electrode plate) has little impact on the formed upper electrode plate, making it easy to ensure process quality. The formed upper electrode plate is made of titanium nitride, which can ensure the conductivity of the upper electrode plate of the capacitor and meet the performance requirements of the capacitor.
[0072] like Figure 11 As shown, the capacitor with the curling iron-shaped structure of the present invention can be arranged in a display manner on the same substrate. The capacitor can be cylindrical or square. If it is cylindrical, it can be arranged in multiple staggered rows, with three capacitors in adjacent rows forming an equilateral triangle distribution. The staggered arrangement can increase the number of capacitors integrated per unit area of substrate, further improving the integration density. The axial ribs of the lower plate can be three or four, evenly spaced circumferentially. The comb back (i.e., the first skeleton) in the lower electrode plate of the curling iron is not water. Instead of resting flat against the substrate, the comb back is erected vertically; its layer plates also do not rest against the substrate at all, but are arranged at different heights along the comb back from bottom to top, similar to a multi-layer bar counter; the upper plate has an inner rib structure opposite to the layer plates, and the inner rib of the upper plate and the layer plates of the lower plate are interspersed in sequence; the upper plate has a columnar sleeve-shaped body, which covers the upper plate and wraps around the lower plate, increasing the relative area of the upper and lower plates, ensuring high capacitance of the capacitor, reducing the area occupied by the substrate, and improving integration.
[0073] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for manufacturing a capacitor having a curling iron-shaped structure, characterized in that, Includes the following steps: S10 has multiple highly doped polysilicon layers and low doped polysilicon layers alternately stacked on the substrate; S20 is designed based on the image layout of a capacitor with a curling iron-shaped structure. A mask is set on the upper end of the polysilicon layer for the first etching to form a polysilicon pillar. S30 is arranged with multiple carbon pillars circumferentially spaced around the edge of the polysilicon pillar, and each carbon pillar covers a portion of the polysilicon pillar. S40 injects dopants into polysilicon pillars through the gaps between multiple carbon pillars, unifying the polysilicon layers exposed between the carbon pillars into polysilicon with a high doping concentration, forming a first skeleton with multiple axial ribs. S50 removes carbon pillars; the selectivity is determined according to the different doping concentrations of the polysilicon pillars, and a second etching is performed to remove the low-doped polysilicon, while the remaining high-doped polysilicon layer forms the layer electrode and the first skeleton in the shape of a hairpin forms the lower electrode. S60 uses a deposition process to form the insulating layer; The S70 uses a deposition process to form an upper electrode plate with inner ribs and a cylindrical sleeve-shaped body that wraps around the lower electrode plate outside the insulation layer.
2. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, The doping concentration of the highly doped polycrystalline silicon layer is not less than 10. 20 pcs / cm 3 .
3. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, The doping concentration of the low-doped polysilicon layer is 0-10. 16 pcs / cm 3 .
4. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, In step S10, the thickness of the low-doped polysilicon layer is equal to the sum of the thickness of the inner rib and twice the thickness of the insulating layer; the thickness of the high-doped polysilicon layer is equal to the thickness of the layer plate.
5. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, In step S30, the carbon column is formed as follows: First, carbon is filled into a substrate containing polycrystalline silicon pillars to bury the polycrystalline silicon pillars; Secondly, multiple photoresist layers are circumferentially spaced around the edge of the polysilicon pillar; Finally, carbon etching is performed to form carbon pillars under the photoresist layer.
6. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, In step S20, the cross-section of the polysilicon pillar is square or circular; in step S30, the cross-section of the carbon pillar is square or circular; if the cross-section of the polysilicon pillar is square, carbon pillars are set at the four corners of the square; if the cross-section of the polysilicon pillar is circular, multiple carbon pillars are evenly spaced around the edge of the polysilicon pillar.
7. The method for manufacturing a capacitor with a curling iron-shaped structure according to claim 1, characterized in that, In step S70, the upper electrode plate outside the insulating layer is formed using a titanium nitride deposition process.
8. A capacitor having a curling iron-shaped structure, characterized in that, It is prepared by the manufacturing method of the capacitor having a curling iron shape structure according to any one of claims 1-7; The capacitor includes an upper plate, a lower plate, and an insulating layer; The lower electrode plate includes a first frame and multiple layered electrode plates. The first frame is vertically fixed on the substrate and has multiple axial ribs arranged circumferentially at intervals, forming a curling iron shape. The layered electrode plates are arranged upward from the substrate along the first frame at different heights from the substrate, and the center of the layered electrode plates is aligned with the axis of the first frame and the two are fixedly connected. The upper electrode plate includes a cylindrical sleeve and multiple inner ribs. The cylindrical sleeve is shaped like a cylindrical cover and covers the lower electrode plate. The inner ribs are spaced apart in the gaps between the electrode plates and are fixedly connected to the inner sidewall of the cylindrical sleeve. The insulating layer is filled between the upper and lower electrode plates to insulate and isolate them.
9. The capacitor with a curling iron-shaped structure according to claim 8, characterized in that, The lower electrode plate has a doping concentration of not less than 10%. 20 pcs / cm 3 Polycrystalline silicon material.
10. The capacitor with a curling iron-shaped structure according to claim 8, characterized in that, The upper electrode plate is made of titanium nitride.