Electromagnetic interference (EMI) and reverse recovery performance improved super junction structure and manufacturing method thereof
By forming a superjunction structure with alternating N-type and P-type pillars and an N-type doped region in the middle of the P-type pillars, the problems of insufficient electromagnetic radiation oscillation and reverse recovery performance of the superjunction structure are solved, and its reliability is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI HUAHONG GRACE SEMICON MFG CORP
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-19
AI Technical Summary
Superjunction structures have shortcomings in electromagnetic radiation oscillation and reverse recovery performance, which limits their reliability.
By forming a superjunction structure with multiple N-type pillars and P-type pillars arranged laterally in an N-type epitaxial layer, and forming an N-type doped region in the middle of the P-type pillars, deep trenches are formed by multiple epitaxial growth and photolithography etching processes and filled with the P-type epitaxial layer to form P-type sub-pillars. Combined with N-type ion implantation technology, the electromagnetic radiation oscillation and reverse recovery performance are improved.
It effectively improves the electromagnetic radiation oscillation and reverse recovery performance of superjunction structures, thereby enhancing the overall performance of superjunction structures.
Smart Images
Figure CN122069765A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to semiconductor integrated circuits, and particularly to a super junction (SJ) process with improved EMI (Electromagnetic Interference) and reverse recovery performance. Background Technology
[0002] A superjunction structure is formed by alternating N-type and P-type pillars. The superjunction structure can significantly improve the conduction performance of MOS devices while reducing chip area. However, the superjunction structure has some shortcomings in electromagnetic radiation oscillation and reverse recovery performance, which limits its reliability. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a superjunction structure and manufacturing method with improved EMI and reverse recovery performance, which can improve the MEI and reverse recovery performance of the superjunction structure.
[0004] To address the aforementioned issues, the EMI and reverse recovery performance-improving superjunction structure provided by this invention is formed in an N-type epitaxial layer. It consists of multiple N-type pillars and P-type pillars arranged alternately in the lateral direction. An N-type pillar and an adjacent P-type pillar form a corresponding superjunction unit. Each of the P-type pillars contains an N-type doped region.
[0005] Meanwhile, in order to solve the above problems, the present invention provides a method for manufacturing a superjunction structure with improved EMI and reverse recovery performance. The superjunction structure is formed in an N-type epitaxial layer and is composed of multiple N-type pillars and P-type pillars arranged alternately in the lateral direction. The N-type epitaxial layer is composed of N-type epitaxial sublayers grown in multiple epitaxial growths stacked together. After each epitaxial growth to form an N-type epitaxial sublayer, deep trenches are formed in selected areas of each N-type epitaxial sublayer through photolithography and etching processes. P-type epitaxy is filled in each deep trench to form P-type subpillars. The corresponding P-type pillars are formed by stacking the P-type subpillars. The bottom surface of the lowest N-type epitaxial sublayer is spaced from the bottom of the P-type subpillar in the same N-type epitaxial sublayer. The bottom of the P-type subpillar in each of the remaining N-type epitaxial sublayers is located within the P-type subpillar in the next N-type epitaxial sublayer. At least one P-type subpillar is selected and N-type ion implanted into it to form an N-type doped region on the top of the P-type subpillar.
[0006] In a further scheme, after determining the P-type sub-column that needs to be implanted with N-type ions, a P-type sub-column is formed in the N-type epitaxial sublayer where the P-type sub-column is located; The upper N-type epitaxial sublayer is further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the upper N-type epitaxial sublayer using photolithography and etching processes, with the bottom of the deep trenches located inside the lower P-type subpillars; N-type ion implantation is performed at the bottom of the deep trench to form an N-type doped region; A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
[0007] In a further embodiment, a first N-type epitaxial sublayer is provided, and a first deep trench is formed in a selected area of the first N-type epitaxial sublayer using photolithography and etching processes. A P-type epitaxial layer is filled in the first deep trench to form a first P-type sub-pillar. A second N-type epitaxial sublayer is formed on the surface of the first N-type epitaxial sublayer using an epitaxial growth process. A second deep trench is formed in a selected area of the second N-type epitaxial sublayer using photolithography and etching processes. The second deep trench penetrates the second N-type epitaxial sublayer and its bottom is located inside the first P-type subpillar. N-type ion implantation is performed at the bottom of the second deep trench to form an N-type doped region in the first P-type sub-pillar; A second P-type sub-pillar is formed by filling a P-type epitaxial layer within the second deep trench. The bottom of the second P-type sub-pillar is simultaneously connected to the N-type doped region and the first P-type sub-pillar. An N-type epitaxial layer is formed by stacking a second N-type epitaxial sublayer and a first N-type epitaxial sublayer, a corresponding P-type column is formed by stacking a second P-type sub-column and a first P-type sub-column, and the N-type column is formed by the N-type epitaxial layers between the P-type columns.
[0008] In a further scheme, after determining the P-type sub-pillar that needs to be implanted with N-type ions, a hard mask layer is formed on the N-type epitaxial sublayer where the P-type sub-pillar is located, and the hard mask layer is used as a shield to form the P-type sub-pillar in the N-type epitaxial sublayer. An N-type doped region is formed on the top of the P-type sub-pillar using the sidewalls of the mask layer; The N-type epitaxial sublayers are further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the epitaxial sublayer using photolithography and etching processes. The bottom of the deep trenches is located inside the N-type doped region and the lower P-type subpillar. A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
[0009] In a further embodiment, a first N-type epitaxial sublayer is provided, and a hard mask layer is formed on the surface of the first N-type epitaxial sublayer; Photolithography and etching processes are performed to define the formation region of the first P-type sub-pillar on the hard mask layer; the N-type epitaxial layer is etched using the hard mask layer as a shield to form the first deep trench. A first P-type sub-pillar is formed by P-type epitaxial filling in the first deep trench; A mask layer sidewall is formed at the opening of the rigid mask layer, and the mask layer sidewall is formed on the surface of the first P-shaped sub-pillar; Using the sidewalls of the mask layer as a shield, N-type ion implantation is performed on the first P-type sub-pillar to form an N-type doped region; Remove the rigid mask layer and the sidewalls of the mask layer; A second N-type epitaxial sublayer is formed on the surface of the first N-type epitaxial sublayer and the first P-type subpillar by epitaxial growth; A second deep trench is formed in the second N-type epitaxial sublayer using photolithography and etching processes. The second deep trench penetrates the second N-type epitaxial sublayer and extends to the first P-type subpillar and the N-type doped region at its bottom. A second P-type sub-pillar is formed by filling a P-type epitaxial layer in the second deep trench, and the second P-type sub-pillar is simultaneously connected to the first P-type sub-pillar and the N-type doped region.
[0010] Furthermore, the N-type epitaxial layer is composed of at least two N-type epitaxial sublayers stacked together.
[0011] Furthermore, the N-type doped region is located at the top of the lowest P-type sub-pillar.
[0012] Furthermore, the N-type doped region is located at the bottom of the uppermost P-type sub-pillar.
[0013] Furthermore, each P-type sub-column is connected to its adjacent P-type sub-column.
[0014] This invention involves forming multiple N-type epitaxial sublayers through multiple epitaxial growths, creating deep trenches in each N-type sublayer, and then filling them with P-type epitaxy to form P-type subpillars. A superjunction structure is formed by the corresponding superposition of the multiple N-type epitaxial sublayers and the P-type subpillars within them. During the layered formation of the superjunction structure, N-type ion implantation is performed on the top of a certain P-type subpillar, resulting in an N-type doped region in the middle of the P-type pillar of the superjunction structure. This effectively improves the electromagnetic radiation oscillation and reverse recovery oscillation of the superjunction structure, thereby enhancing its performance. Attached Figure Description
[0015] Figure 1 , Figure 2 This is a simulation diagram of a superjunction structure; Figures 3 to 8 This is a schematic diagram of the device structure in each step of the manufacturing method of the superjunction structure according to Embodiment 1 of the present invention; Figures 9 to 15 This is a schematic diagram of the device structure in each step of the manufacturing method of the superjunction structure in Embodiment 2 of the present invention. Detailed Implementation
[0016] The embodiments of the present invention are described below with reference to the accompanying drawings and specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Specific details are set forth in the following description to provide a thorough understanding of the present invention; however, the present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be based on different viewpoints and applications. Those skilled in the art can make various similar extensions and substitutions without departing from the spirit of the present invention.
[0017] The EMI and reverse recovery performance improved superjunction structure of the present invention is formed in an N-type epitaxial layer, which is composed of multiple N-type pillars and P-type pillars arranged laterally alternately. An N-type pillar and an adjacent P-type pillar form a corresponding superjunction unit; an N-type doped region is formed in each of the P-type pillars.
[0018] In the manufacturing method of the EMI and reverse recovery performance improved superjunction structure of the present invention, the N-type epitaxial layer is composed of N-type epitaxial sublayers grown in multiple epitaxial growths stacked together. After each epitaxial growth to form an N-type epitaxial sublayer, a deep trench is formed in a selected area of each N-type epitaxial sublayer by photolithography and etching processes. P-type epitaxy is filled in each deep trench to form a P-type sub-pillar. The P-type sub-pillars are stacked to form a corresponding P-type pillar. The bottom surface of the lowest N-type epitaxial sublayer is spaced from the bottom of the P-type subpillar in the same N-type epitaxial sublayer. The bottom of the P-type subpillar in each of the remaining N-type epitaxial sublayers is located within the P-type subpillar in the next N-type epitaxial sublayer. At least one P-type subpillar is selected and N-type ion implanted into it to form an N-type doped region on the top of the P-type subpillar.
[0019] In this embodiment of the invention, multiple N-type epitaxial sublayers are formed through multiple epitaxial growths. After forming deep trenches in each N-type epitaxial sublayer, P-type epitaxy is filled to form P-type subpillars. A superjunction structure is formed by correspondingly stacking the multiple N-type epitaxial sublayers and the P-type subpillars within the N-type epitaxial sublayers. During the layered formation of the superjunction structure, N-type ion implantation is performed on the top of a certain P-type subpillar, so that an N-type doped region is formed in the middle of the P-type pillar of the superjunction structure. This can effectively improve the electromagnetic radiation oscillation and reverse recovery oscillation of the superjunction structure, thereby improving the performance of the superjunction structure. Example 1
[0020] In this embodiment of the invention, after determining the P-type sub-column that needs to be implanted with N-type ions, the N-type epitaxial sublayer where the P-type sub-column is located is first formed, and then the P-type sub-column is formed in the N-type epitaxial sublayer. The upper N-type epitaxial sublayer is further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the upper N-type epitaxial sublayer using photolithography and etching processes, with the bottom of the deep trenches located inside the lower P-type subpillars; N-type ion implantation is performed at the bottom of the deep trench to form an N-type doped region; A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
[0021] The manufacturing process of a superjunction structure will be explained below using two N-type epitaxial sublayers as an example.
[0022] like Figure 3 As shown, a first N-type epitaxial sublayer 101 is provided, and a first deep trench 201 is formed in a selected area of the first N-type epitaxial sublayer 101 using photolithography and etching processes.
[0023] like Figure 4 As shown, a first P-type sub-pillar 102 is formed by filling a P-type epitaxial layer in the first deep trench 201.
[0024] like Figure 5 As shown, a second N-type epitaxial sublayer 104 is formed on the surface of the first N-type epitaxial sublayer 101 using an epitaxial growth process.
[0025] like Figure 6 As shown, a second deep trench 202 is formed in a selected area of the second N-type epitaxial sublayer 104 using photolithography and etching processes. The second deep trench 202 penetrates the second N-type epitaxial sublayer 104 and its bottom is located within the first P-type subpillar 102.
[0026] like Figure 7 As shown, N-type ion implantation is performed on the bottom of the second deep trench 202 to form an N-type doped region 103 in the first P-type sub-pillar 102.
[0027] like Figure 8 As shown, a second P-type sub-pillar 105 is formed by filling a P-type epitaxial layer in the second deep trench 202. The bottom of the second P-type sub-pillar 105 is simultaneously connected to the N-type doped region 103 and the first P-type sub-pillar 102.
[0028] An N-type epitaxial layer is formed by stacking a second N-type epitaxial sublayer 104 and a first N-type epitaxial sublayer 101, and a corresponding P-type column is formed by stacking a second P-type sub-column 105 and a first P-type sub-column 102. The N-type column is formed by the N-type epitaxial layers between the P-type columns.
[0029] Of course, this embodiment does not limit the selection of which P-type subpillar in the N-type epitaxial sublayer to perform N-type ion implantation; the above is merely an example. For instance, the superjunction structure may contain three N-type epitaxial sublayers with an N-type doped region formed on top of the middle N-type epitaxial sublayer, or the superjunction structure may contain four N-type epitaxial sublayers with an N-type doped region formed on top of the second N-type epitaxial sublayer from the top, and so on.
[0030] In this embodiment, an upper N-type epitaxial sublayer is first formed and a deep trench is formed by photolithography and etching. Then, N-type ion implantation is performed on the lower P-type subpillar at the bottom of the deep trench, thereby forming an N-type doped region inside the P-type pillar to improve the electromagnetic radiation oscillation and reverse recovery performance of the superjunction structure. Example 2
[0031] In this embodiment of the invention, after determining the P-type sub-pillar that needs to be implanted with N-type ions, a hard mask layer is formed on the N-type epitaxial sublayer where the P-type sub-pillar is located, and the P-type sub-pillar is formed in the N-type epitaxial sublayer by using the hard mask layer as a shield. An N-type doped region is formed on the top of the P-type sub-pillar using the sidewalls of the mask layer; The N-type epitaxial sublayers are further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the epitaxial sublayer using photolithography and etching processes. The bottom of the deep trenches is located inside the N-type doped region and the lower P-type subpillar. A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
[0032] The manufacturing process of the superjunction structure in this embodiment will be described below using two N-type epitaxial sublayers as an example.
[0033] like Figure 9 As shown, a first N-type epitaxial sublayer 101 is provided, and a hard mask layer 106 is formed on the surface of the first N-type epitaxial sublayer 101.
[0034] Photolithography and etching processes are performed to define the formation area of the first P-type sub-pillar on the hard mask layer 106; the N-type epitaxial layer 101 is etched using the hard mask layer 106 as a shield to form the first deep trench 201.
[0035] like Figure 10 As shown, a first P-type sub-pillar 102 is formed by P-type extension filling in the first deep trench 201.
[0036] like Figure 11 As shown, a mask layer sidewall 107 is formed at the opening of the rigid mask layer 106, and the mask layer sidewall 107 is formed on the surface of the first P-shaped sub-pillar 102.
[0037] like Figure 12 As shown, the mask layer sidewall 107 is used as a shield to perform N-type ion implantation on the first P-type sub-pillar 102 to form an N-type doped region 103.
[0038] like Figure 13 As shown, the rigid mask layer 106 and the mask layer sidewall 107 are removed.
[0039] like Figure 14 As shown, a second N-type epitaxial sublayer 104 is formed on the surface of the first N-type epitaxial sublayer 101 and the first P-type subpillar 102 by epitaxial growth.
[0040] like Figure 15 As shown, a second deep trench is formed in the second N-type epitaxial sublayer 104 using photolithography and etching processes. The second deep trench penetrates the second N-type epitaxial sublayer 104 and extends to the first P-type subpillar 102 and the N-type doped region 103 at its bottom.
[0041] A second P-type sub-pillar 105 is formed by filling a P-type epitaxial layer in the second deep trench. The second P-type sub-pillar 105 is simultaneously connected to the first P-type sub-pillar 102 and the N-type doped region 103.
[0042] In this embodiment, the N-type epitaxial layer is composed of at least two N-type epitaxial sublayers stacked together. The example above uses the formation of an N-type doped region in the first P-type subpillar as an example; however, the number of N-type epitaxial sublayers and the selection of which P-type subpillar within the N-type epitaxial sublayer is chosen for N-type ion implantation are not limited; the above is merely an illustrative example. The N-type doped region can be located at the top of the bottommost P-type subpillar or at the bottom of the topmost P-type subpillar. For example, the superjunction structure can contain three N-type epitaxial sublayers with an N-type doped region formed on top of the middle N-type epitaxial sublayer, or the superjunction structure can contain four N-type epitaxial sublayers with an N-type doped region formed on top of the second N-type epitaxial sublayer from the top, and so on.
[0043] In this embodiment, when forming the superjunction structure, N-type doped regions are formed by direct ion implantation in the designed P-type subpillar using a hard mask layer and mask layer sidewalls. Then, an upper N-type epitaxial sublayer is formed by epitaxial growth, and deep trenches are etched in the N-type epitaxial sublayer and filled with P-type epitaxy to form P-type subpillars, thereby improving the electromagnetic radiation oscillation and reverse recovery performance of the superjunction structure.
[0044] The present invention has been described in detail above through specific embodiments. These embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to the above-described implementation methods. Equivalent substitutions and improvements made by those skilled in the art without departing from the principles of the present invention should be considered within the scope of the technology protected by the present invention.
Claims
1. A superjunction structure with improved EMI and reverse recovery performance, characterized in that, The superjunction structure is formed in an N-type epitaxial layer and is composed of multiple N-type pillars and P-type pillars arranged laterally alternately. An N-type pillar and an adjacent P-type pillar form a corresponding superjunction unit. An N-type doped region is formed in each of the P-type pillars.
2. A method for manufacturing a superjunction structure with improved EMI and reverse recovery performance, characterized in that, The superjunction structure is formed in an N-type epitaxial layer and is composed of multiple N-type pillars and P-type pillars arranged alternately in the transverse direction. The N-type epitaxial layer is composed of N-type epitaxial sublayers grown in multiple epitaxial growths stacked together. After each epitaxial growth to form an N-type epitaxial sublayer, deep trenches are formed in selected areas of each N-type epitaxial sublayer through photolithography and etching processes. P-type epitaxy is filled in each deep trench to form P-type subpillars. The corresponding P-type pillars are formed by stacking the P-type subpillars. The bottom surface of the lowest N-type epitaxial sublayer is spaced from the bottom of the P-type subpillar in the same N-type epitaxial sublayer. The bottom of the P-type subpillar in each of the remaining N-type epitaxial sublayers is located within the P-type subpillar in the next N-type epitaxial sublayer. At least one P-type subpillar is selected and N-type ion implanted into it to form an N-type doped region on the top of the P-type subpillar.
3. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, After identifying the P-type sub-column that needs to be implanted with N-type ions, a P-type sub-column is formed in the N-type epitaxial sublayer where the P-type sub-column is located. The upper N-type epitaxial sublayer is further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the upper N-type epitaxial sublayer using photolithography and etching processes, with the bottom of the deep trenches located inside the lower P-type subpillars; N-type ion implantation is performed at the bottom of the deep trench to form an N-type doped region; A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
4. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 3, characterized in that, A first N-type epitaxial sublayer is provided, and a first deep trench is formed in a selected area of the first N-type epitaxial sublayer using photolithography and etching processes. A first P-type subpillar is formed by filling the first deep trench with a P-type epitaxial layer. A second N-type epitaxial sublayer is formed on the surface of the first N-type epitaxial sublayer using an epitaxial growth process. A second deep trench is formed in a selected area of the second N-type epitaxial sublayer using photolithography and etching processes. The second deep trench penetrates the second N-type epitaxial sublayer and its bottom is located inside the first P-type subpillar. N-type ion implantation is performed at the bottom of the second deep trench to form an N-type doped region in the first P-type sub-pillar; A second P-type sub-pillar is formed by filling a P-type epitaxial layer within the second deep trench. The bottom of the second P-type sub-pillar is simultaneously connected to the N-type doped region and the first P-type sub-pillar. An N-type epitaxial layer is formed by stacking a second N-type epitaxial sublayer and a first N-type epitaxial sublayer, a corresponding P-type column is formed by stacking a second P-type sub-column and a first P-type sub-column, and the N-type column is formed by the N-type epitaxial layers between the P-type columns.
5. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, After determining the P-type sub-pillar that needs to be implanted with N-type ions, a hard mask layer is formed on the N-type epitaxial sublayer where the P-type sub-pillar is located. The hard mask layer is used as a shield to form the P-type sub-pillar in the N-type epitaxial sublayer. An N-type doped region is formed on the top of the P-type sub-pillar using the sidewalls of the mask layer; The N-type epitaxial sublayers are further formed using an epitaxial growth process; Deep trenches are formed in selected areas of the epitaxial sublayer using photolithography and etching processes. The bottom of the deep trenches is located inside the N-type doped region and the lower P-type subpillar. A P-type epitaxial layer is filled in the deep trench to form a P-type sub-pillar, which is connected to the N-type doped region and the lower P-type sub-pillar.
6. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 5, characterized in that, A first N-type epitaxial sublayer is provided, and a hard mask layer is formed on the surface of the first N-type epitaxial sublayer; Photolithography and etching processes are performed to define the formation region of the first P-type sub-pillar on the hard mask layer; The N-type epitaxial layer is etched using the hard mask layer as a shield to form a first deep trench; A first P-type sub-pillar is formed by P-type epitaxial filling in the first deep trench; A mask layer sidewall is formed at the opening of the rigid mask layer, and the mask layer sidewall is formed on the surface of the first P-shaped sub-pillar; Using the sidewalls of the mask layer as a shield, N-type ion implantation is performed on the first P-type sub-pillar to form an N-type doped region; Remove the rigid mask layer and the sidewalls of the mask layer; A second N-type epitaxial sublayer is formed on the surface of the first N-type epitaxial sublayer and the first P-type subpillar by epitaxial growth; A second deep trench is formed in the second N-type epitaxial sublayer using photolithography and etching processes. The second deep trench penetrates the second N-type epitaxial sublayer and extends to the first P-type subpillar and the N-type doped region at its bottom. A second P-type sub-pillar is formed by filling a P-type epitaxial layer in the second deep trench, and the second P-type sub-pillar is simultaneously connected to the first P-type sub-pillar and the N-type doped region.
7. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, The N-type epitaxial layer is composed of at least two N-type epitaxial sublayers stacked together.
8. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, The N-type doped region is located at the top of the bottommost P-type sub-pillar.
9. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, The N-type doped region is located at the bottom of the uppermost P-type sub-pillar.
10. The method for manufacturing the EMI and reverse recovery performance improved superjunction structure according to claim 2, characterized in that, Each P-type sub-column is connected to its adjacent P-type sub-column.