Semiconductor structure and method for forming the same

Abstract

A semiconductor structure and a method for forming the same include: a substrate; a collector region located on the substrate; a base region located on the collector region, the base region having a doping type opposite to that of the collector region; and a transition region located within the base region, the transition region having a doping type opposite to that of the base region, wherein the bottom of the transition region is higher than the bottom of the base region and the top of the transition region is lower than the top of the base region. Because the transition region can serve as an extension of the collector region, the effective base region is narrowed, thereby increasing the current amplification factor β. When measuring the breakdown voltage (BVceo) between the collector and emitter regions, the base region located at the bottom of the transition region helps deplete the transition region, thereby increasing the breakdown voltage between the collector and emitter regions. Furthermore, the collector region cannot be simply replaced by the transition region because the collector region surrounds the base region located at the top and bottom of the transition region, effectively isolating current from flowing directly to the substrate and preventing the generation of noise.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a semiconductor structure and a method for forming the same. Background Art

[0002] Bipolar junction transistor (BJT) is an important semiconductor device in semiconductor integrated circuits. Bipolar junction transistor has an amplifying effect and is widely used in various circuit designs in the industrial and consumer electronics fields, such as detection circuits, rectifier circuits, amplifier circuits, switching circuits, voltage regulator circuits, signal modulation circuits, etc.

[0003] According to the different structures of bipolar junction transistors, bipolar junction transistors can be divided into two types: NPN type and PNP type. Bipolar junction transistors are also called semiconductor triodes. They have three external electrodes: collector, emitter and base. The collector is drawn from the collector region of the bipolar junction transistor, the emitter is drawn from the emitter region of the bipolar junction transistor, and the base is drawn from the base region of the bipolar junction transistor.

[0004] However, the current amplification factor β and the breakdown voltage (BVceo) between the collector region and the emitter region of the bipolar junction transistor provided by the prior art cannot be increased simultaneously. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a semiconductor structure and a method for forming the same, which can simultaneously increase the current amplification factor β and the breakdown voltage (BVceo) between the collector region and the emitter region.

[0006] To solve the above problems, the present invention provides a semiconductor structure, comprising: a substrate; a collector region located on the substrate; a base region located on the collector region, the doping type of the base region being opposite to the doping type of the collector region, and the bottom of the base region being higher than the bottom of the collector region; a transition region located within the base region, the doping type of the transition region being opposite to the doping type of the base region, the bottom of the transition region being higher than the bottom of the base region, and the top of the transition region being lower than the top of the base region; an emitter region located on the base region, the doping type of the emitter region being opposite to the doping type of the base region, and the bottom of the emitter region being higher than the bottom of the base region.

[0007] Optionally, it also includes: a collector located on the collector region, the collector having the same doping type as the collector region, and the doping concentration of the collector being greater than the doping concentration of the collector region; and a base located on the base region, the base having the same doping type as the base region, and the doping concentration of the base being greater than the doping concentration of the base region.

[0008] Optionally, it further includes: an annular isolation structure located on the base region, the annular isolation structure surrounds the emitter region and a portion of the base region, and the bottom of the annular isolation structure is higher than the bottom of the base region.

[0009] Optionally, it also includes: a first isolation structure located on the base region and the collector region, the first isolation structure surrounds the base region, and the bottom of the first isolation structure is higher than the bottom of the base region; a second isolation structure located on the substrate and the collector region, the second isolation structure surrounds the collector region, and the bottom of the second isolation structure is higher than the bottom of the collector region.

[0010] Optionally, the collector region is doped with N-type doping, the base region is doped with P-type doping, the emitter region is doped with N-type doping, and the transition region is doped with N-type doping.

[0011] Optionally, the collector region is doped with P-type doping, the base region is doped with N-type doping, the emitter region is doped with P-type doping, and the transition region is doped with P-type doping.

[0012] Optionally, the doping ions of the N-type doping are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the doping ions of the P-type doping are P-type ions, and the P-type ions include: boron ions or indium ions.

[0013] Correspondingly, the present invention also provides a method for forming a semiconductor structure, comprising: providing a substrate; forming a collector region on the substrate; forming a base region on the collector region, the doping type of the base region being opposite to the doping type of the collector region, and the bottom of the base region being higher than the bottom of the collector region; forming a transition region in the base region, the doping type of the transition region being opposite to the doping type of the base region, the bottom of the transition region being higher than the bottom of the base region, and the top of the transition region being lower than the top of the base region; forming an emitter region on the base region, the doping type of the emitter region being opposite to the doping type of the base region, and the bottom of the emitter region being higher than the bottom of the base region.

[0014] Optionally, it also includes: forming a collector on the collector region, the collector having the same doping type as the collector region, and the doping concentration of the collector being greater than the doping concentration of the collector region; forming a base on the base region, the base having the same doping type as the base region, and the doping concentration of the base being greater than the doping concentration of the base region.

[0015] Optionally, the method further includes: forming an annular isolation structure on the base region, wherein the annular isolation structure surrounds the emitter region and a portion of the base region, and the bottom of the annular isolation structure is higher than the bottom of the base region.

[0016] Optionally, it also includes: forming a first isolation structure on the base region and the collector region, the first isolation structure surrounding the base region, and the bottom of the first isolation structure is higher than the bottom of the base region; forming a second isolation structure on the substrate and the collector region, the second isolation structure surrounding the collector region, and the bottom of the second isolation structure is higher than the bottom of the collector region.

[0017] Optionally, the collector region is doped with N-type doping, the base region is doped with P-type doping, the emitter region is doped with N-type doping, and the transition region is doped with N-type doping.

[0018] Optionally, the collector region is doped with P-type doping, the base region is doped with N-type doping, the emitter region is doped with P-type doping, and the transition region is doped with P-type doping.

[0019] Optionally, the doping ions of the N-type doping are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the doping ions of the P-type doping are P-type ions, and the P-type ions include: boron ions or indium ions.

[0020] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0021] In the structure of the technical solution of the present invention, a transition region is located within the base region. The doping type of the transition region is opposite to that of the base region, and the bottom of the transition region is higher than the bottom of the base region, while the top of the transition region is lower than the top of the base region. Because the transition region and the collector region have the same doping type, the transition region can serve as an extension of the collector region, thereby narrowing the effective base region and increasing the current amplification factor β. When testing the breakdown voltage (BVceo) between the collector region and the emitter region, the base region located at the bottom of the transition region helps deplete the transition region, thereby increasing the breakdown voltage between the collector region and the emitter region.

[0022] In addition, the collector region cannot be simply replaced by the transition region because the collector region surrounds the base region at the top and bottom of the transition region, effectively isolating the current from flowing directly to the substrate and avoiding the generation of noise.

[0023] In the formation method of the technical solution of the present invention, the final current amplification factor β is increased by forming a transition region within the base region. In addition, the doping type of the transition region is opposite to that of the base region. When testing the breakdown voltage (BVceo) between the collector region and the emitter region, the base region located at the bottom of the transition region helps deplete the transition region, thereby increasing the breakdown voltage (BVceo) between the collector region and the emitter region. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figures 1 to 2 It is a structural diagram of a semiconductor structure;

[0025] Figure 3 It is a structural diagram of another semiconductor structure;

[0026] Figures 4 to 11 It is a schematic structural diagram of each step of an embodiment of a semiconductor structure and a method for forming the same according to the present invention. DETAILED DESCRIPTION

[0027] As described in the background art, the current amplification factor β and the breakdown voltage (BVceo) between the collector and emitter regions of the bipolar junction transistor provided by the prior art cannot be increased simultaneously.

[0028] Please refer to Figure 1 , including a substrate 100; a collector region 101 located on the substrate 100; a base region 102 located on the collector region 101, the doping type of the base region 102 is opposite to the doping type of the collector region 101, and the bottom of the base region 102 is higher than the bottom of the collector region 101.

[0029] Please refer to Figure 2 , an annular isolation structure 103, a first isolation structure 104 and a second isolation structure 105 located on the substrate 100; an emitter region 106 located on the base region 102 surrounded by the annular isolation structure 103, the doping type of the emitter region 106 being opposite to the doping type of the base region 102; a collector electrode 107 located on the collector region 101 between the first isolation structure 104 and the second isolation structure 105, the collector electrode 107 being the same as the doping type of the collector region 101, and the doping concentration of the collector electrode 107 being greater than the doping concentration of the collector region 101; a base electrode 108 located on the base region 102 between the first isolation structure 104 and the annular isolation structure 103, the base electrode 108 being the same as the doping type of the base region 102, and the doping concentration of the base electrode 108 being greater than the doping concentration of the base region 102.

[0030] In this embodiment, since the formed bipolar junction transistor is a parasitic device, the width d1 of the base region 102 in the bipolar junction transistor (i.e., the distance from the top to the bottom of the base region) is fixed and not easy to change. Since the width of the base region 102 is large, after the majority carriers in the emitter region 106 are injected into the base region 102, and in the process of the majority carriers in the emitter region 106 crossing the base region 102, the recombination loss of the majority carriers in the emitter region 106 and the majority carriers in the base region 102 will increase, thereby reducing the number of majority carriers in the emitter region 106 reaching the collector region 101, and thereby reducing the current in the collector region 101, so that the final current amplification factor β is smaller.

[0031] In order to solve the above problems, another method for forming a semiconductor structure is proposed, which will be described in detail below with reference to the accompanying drawings.

[0032] Please refer to Figure 3 This embodiment continues to describe the method for forming a semiconductor structure based on the above embodiment. The difference between this embodiment and the above embodiment is that it also includes: a transition region 109 located in the base region 102, the doping type of the transition region 109 is opposite to the doping type of the base region 102, and the top of the transition region 109 is lower than the top of the base region 102, and the bottom of the transition region 109 is in contact with the collector region 101.

[0033] In this embodiment, since the transition region 109 is formed in the base region 102, the doping type of the transition region 109 is opposite to the doping type of the base region 102, and the top of the transition region 109 is lower than the top of the base region 102, and the bottom of the transition region 109 is in contact with the collector region 101, which makes the transition region 109 and the collector region 101 form a whole, and the width d1 of the base region 102 becomes smaller. After the majority carriers of the emitter region 106 are injected into the base region 102, and in the process of the majority carriers of the emitter region 106 crossing the base region 102, the recombination loss of the majority carriers of the emitter region 106 and the majority carriers in the base region 102 is reduced, and the number of majority carriers of the emitter region 106 reaching the collector region 101 is increased, thereby increasing the current of the collector region 101, so that the final current amplification factor β is increased.

[0034] However, since the bottom of the transition region 109 is in contact with the collector region 101 to form a whole, when the width d1 of the base region 102 becomes smaller, the distance between the collector region 101 and the emitter region 106 becomes smaller, thereby reducing the breakdown voltage (BVceo) between the collector region 101 and the emitter region 106, which can easily cause leakage of the semiconductor structure, thereby affecting the performance of the semiconductor structure.

[0035] On this basis, the present invention provides a semiconductor structure and a method for forming the same, comprising a transition region located within the base region, wherein the doping type of the transition region is opposite to that of the base region, and the bottom of the transition region is higher than the bottom of the base region, while the top of the transition region is lower than the top of the base region. Because the transition region and the collector region share the same doping type, the transition region can serve as an extension of the collector region, thereby narrowing the effective base region and increasing the current amplification factor β. During the breakdown voltage (BVceo) test between the collector region and the emitter region, the base region located at the bottom of the transition region helps deplete the transition region, thereby increasing the breakdown voltage between the collector region and the emitter region. Furthermore, the collector region cannot be simply replaced by the transition region, as the collector region surrounds the base region located at the top and bottom of the transition region, effectively isolating the current from flowing directly to the substrate and preventing the generation of noise.

[0036] Because the distance between the top of the transition region and the top of the base region is smaller than the distance between the top of the collector region and the top of the base region, after the majority carriers of the emitter region are injected into the base region, the recombination loss between the majority carriers of the emitter region and the majority carriers in the base region is reduced during the process of the majority carriers of the emitter region crossing the base region to reach the transition region, thereby increasing the number of majority carriers of the emitter region reaching the transition region. Since the circuit between the transition region and the collector region is conductive when power is applied, the majority carriers of the emitter region reaching the transition region can be directly collected by the collector region to form the collector region current, thereby increasing the final current amplification factor β. In addition, because the transition region is formed in the base region and the doping type of the transition region is opposite to that of the base region, two PN junctions are added to the base region, thereby increasing the resistivity of the base region and thereby increasing the breakdown voltage (BVceo) between the collector region and the emitter region, thereby improving the performance of the semiconductor structure.

[0037] 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.

[0038] Figures 4 to 11 It is a structural schematic diagram of a formation process of a semiconductor structure according to an embodiment of the present invention.

[0039] Please refer to Figure 4 , providing a substrate.

[0040] The substrate 200 is one of single crystal silicon, polycrystalline silicon, amorphous silicon, or silicon on insulator. The substrate 200 may also be a Si substrate, a Ge substrate, a GeSi substrate, or a GaAs substrate. The substrate 200 may be an N-type substrate, a P-type substrate, or an intrinsic substrate. In this embodiment, the substrate 200 is a Si substrate.

[0041] Please continue to refer to Figure 4 , a collector region 201 is formed on the substrate 200 .

[0042] The process for forming the collector region 201 is a first doping process, and the doping type of the first doping is determined according to the type of the bipolar junction transistor to be formed. Specifically, when the bipolar junction transistor to be formed is an NPN transistor, the doping type of the collector region 201 is N-type doping, and the doping type of the first doping process is N-type doping; when the bipolar junction transistor to be formed is a PNP transistor, the doping type of the collector region 201 is P-type doping, and the doping type of the first doping process is P-type doping.

[0043] The doping ions of the N-type doping are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the doping ions of the P-type doping are P-type ions, and the P-type ions include: boron ions or indium ions.

[0044] In this embodiment, the bipolar junction transistor formed is an NPN transistor, and the doping type of the first doping process is N-type doping. In other embodiments, the bipolar junction transistor formed is a PNP transistor, and the doping type of the first doping process is P-type doping.

[0045] In this embodiment, the method of the first doping process is: forming a patterned first photoresist layer (not shown) on the surface of the substrate 200; using the patterned first photoresist layer as a mask, implanting N-type ions into the substrate 200 to form the collector region 201 on the substrate 200; after forming the collector region 201, removing the patterned first photoresist layer.

[0046] In this embodiment, before performing the first doping process, the process further includes: forming a sacrificial oxide layer (not shown) on the surface of the substrate 200. The sacrificial oxide layer can prevent lattice damage to the substrate surface during N-type ion implantation.

[0047] In this embodiment, after the first doping process is performed, the method further includes: performing a first annealing process on the substrate 200 to activate the implanted N-type ions and diffuse the N-type ions to a certain extent.

[0048] Please refer to Figure 5, a base region 202 is formed on the collector region 201 , the doping type of the base region 202 is opposite to the doping type of the collector region 201 , and the bottom of the base region 202 is higher than the bottom of the collector region 201 .

[0049] In this embodiment, the doping type of the base region 202 is P-type doping; in other embodiments, the doping type of the base region may also be N-type doping.

[0050] In this embodiment, the process of forming the base region 202 adopts a second doping process, and the method of the second doping process includes: forming a patterned second photoresist layer (not shown) on the surface of the substrate 200, and the patterned second photoresist layer exposes part of the surface of the collector region 201; using the patterned second photoresist layer as a mask, implanting P-type ions into the substrate 200 to form the base region 202 on the collector region 201; after forming the base region 202, removing the patterned second photoresist layer.

[0051] In this embodiment, after the second doping process, the method further includes: performing a second annealing treatment on the substrate 200 to activate the implanted P-type ions and diffuse the P-type ions to a certain extent.

[0052] In this embodiment, the second annealing treatment and the first annealing treatment are performed in the same process.

[0053] Please refer to Figure 6 A transition region 203 is formed in the base region 202 , wherein the doping type of the transition region 203 is opposite to the doping type of the base region 202 , and the bottom of the transition region 203 is higher than the bottom of the base region 202 , and the top of the transition region 203 is lower than the top of the base region 202 .

[0054] The transition region 203 within the base region 202 has a doping type opposite to that of the base region 202, and the bottom of the transition region 203 is higher than the bottom of the base region 202, while the top of the transition region 203 is lower than the top of the base region 202. Since the transition region 203 has the same doping type as the collector region 201, the transition region 203 can serve as an extension of the collector region 201, thereby narrowing the effective base region 202 and increasing the current amplification factor β. When testing the breakdown voltage (BVceo) between the collector region 201 and the emitter region, the base region 202 at the bottom of the transition region 203 helps deplete the transition region 203, thereby increasing the breakdown voltage between the collector region 201 and the emitter region.

[0055] In addition, the collector region 201 cannot be simply replaced by the transition region 203 because the collector region 201 surrounds the base region 202 located at the top and bottom of the transition region 203, effectively isolating the current from flowing directly to the substrate 200 and avoiding the generation of noise.

[0056] In this embodiment, the doping type of the transition region 203 is N-type doping; in other embodiments, the doping type of the transition region is P-type doping.

[0057] After forming the transition region 203, the method further includes: forming an annular isolation structure on the base region 202, wherein the bottom of the annular isolation structure is higher than the bottom of the base region 202; forming a first isolation structure on the base region 202 and the collector region 201, wherein the first isolation structure surrounds the base region 202 and the bottom of the first isolation structure is higher than the bottom of the base region 202; and forming a second isolation structure on the substrate 200 and the collector region 201, wherein the second isolation structure surrounds the collector region 201 and the bottom of the second isolation structure is higher than the bottom of the collector region 201. For the specific formation process of the annular isolation structure, the first isolation structure and the second isolation structure, please refer to Figures 7 to 9 .

[0058] Please refer to Figure 7 , an annular groove 204 is formed on the base region 202 , the annular groove 204 surrounds a portion of the base region 202 , and the bottom of the annular groove 204 is higher than the bottom of the base region 202 .

[0059] In this embodiment, while forming the annular trench 204, the following steps are also included: forming a first trench 205 on the base region 202 and the collector region 201, wherein the first trench 205 surrounds the base region 202 and has a bottom higher than the bottom of the base region 202; and forming a second trench 206 on the substrate 200 and the collector region 201, wherein the second trench 206 surrounds the collector region 201 and has a bottom higher than the bottom of the collector region 201. By simultaneously forming the annular trench 204, the first trench 205, and the second trench 206, process steps can be effectively saved and production efficiency can be improved.

[0060] The annular trench 204 has the function of filling the annular trench 204 with dielectric material to form an annular isolation structure. After the base and emitter are formed, the annular isolation structure serves to electrically isolate the base and emitter.

[0061] The functions of the first trench 205 and the second trench 206 are: subsequently, a dielectric material is filled in the first trench 205 to form a first isolation structure, and after the base and the collector are subsequently formed, the first isolation structure serves to electrically isolate the base and the emitter region; subsequently, a dielectric material is filled in the second trench 206 to form a second isolation structure, and after the collector is subsequently formed, the second isolation structure serves to electrically isolate the collector from other circuits.

[0062] The annular shape of the annular groove 204 is a closed annular shape, wherein the annular shape is a circular annular shape, an elliptical annular shape, a square annular shape or a polygonal annular shape. In this embodiment, the annular shape of the annular groove 204 is a circular annular shape.

[0063] In this embodiment, in order to improve the isolation capability of the first isolation structure and the second isolation structure formed subsequently, the first trench 205 and the second trench 206 are both annular trenches, wherein the first trench 205 surrounds the base region 202 and the second trench 206 surrounds the collector region 201.

[0064] In this embodiment, the process method for forming the annular groove 204, the first groove 205 and the second groove 206 includes: forming a patterned mask layer (not shown) on the surface of the substrate 200, the patterned mask layer having a ring opening, a first opening and a second opening (not shown); using the patterned mask layer as a mask, etching away part of the thickness of the substrate, the collector region and the base region, forming the annular groove 204 on the base region, forming the first groove 205 between the base region 202 and the collector region 201, and forming the second groove 206 between the collector region 201 and the substrate 200.

[0065] In this embodiment, the annular groove 204 , the first groove 205 and the second groove 206 are formed by etching using a dry etching process.

[0066] In this embodiment, the bottom size of the annular groove 204 is smaller than the top size of the annular groove 204, and the annular groove 204 presents an inverted trapezoidal cross-sectional morphology. The subsequently formed annular isolation structure also has an inverted trapezoidal cross-sectional morphology. Therefore, when the annular isolation structure is subsequently etched, since the surface size of the annular isolation structure is larger than the bottom size, the process window for forming the mask layer for etching the annular isolation structure is larger, thereby improving the accuracy of the position of forming the mask layer.

[0067] Please refer to Figure 8 and Figure 9 , Figure 9 yes Figure 8In the cross-sectional schematic diagram along line AA, the annular groove 204, the first groove 205 and the second groove 206 are filled with a dielectric material layer, an annular isolation structure 207 is formed on the base region 202, a first isolation structure 208 is formed between the base region 202 and the collector region 201, and a second isolation structure 209 is formed between the collector region 201 and the substrate 200.

[0068] The first isolation structure 208 surrounds the base region 202 , and the bottom of the first isolation structure 208 is higher than the bottom of the base region 202 ; the second isolation structure 209 surrounds the collector region 201 , and the bottom of the second isolation structure 209 is higher than the bottom of the collector region 201 .

[0069] The dielectric material layer is made of silicon oxide or silicon oxynitride. In this embodiment, the dielectric material layer is made of silicon oxide and is formed using a high-aspect-ratio chemical vapor deposition process. The process parameters of the high-aspect-ratio chemical vapor deposition process are as follows: the reaction gases include a silicon source gas and an oxygen source gas, wherein the silicon source gas flow rate is 20 sccm to 2000 sccm, the oxygen source gas flow rate is 10 sccm to 1000 sccm, the reaction chamber pressure is 1 mTorr to 50 Torr, and the reaction chamber temperature is 450°C to 800°C.

[0070] In this embodiment, before forming the dielectric material layer, a thermal oxidation process is used to form a linear oxide layer (not shown) on the bottom and sidewall surfaces of the annular trench 204, the first trench 205, and the second trench 206. By forming the oxide layer, the interface performance between the dielectric material layer and the sidewalls of the annular trench 204, the first trench 205, and the second trench 206 is improved.

[0071] In other embodiments, the annular isolation structure, the first isolation structure, and the second isolation structure may also be formed before forming the base region and the collector region.

[0072] Please refer to Figure 10 , Figure 10 and Figure 9 In the same viewing direction, an emitter region 210 is formed on the base region 202 . The doping type of the emitter region 210 is opposite to that of the base region 202 , and the bottom of the emitter region 210 is higher than the bottom of the base region 202 .

[0073] In this embodiment, the emitter region 210 is specifically formed in the base region 202 surrounded by the annular isolation structure 207 .

[0074] In this embodiment, the doping type of the emitter region 210 is N-type doping; in other embodiments, the doping type of the emitter region may also be P-type doping.

[0075] In this embodiment, the process of forming the emitter region 210 adopts a third doping process, and the method of the third doping process includes: forming a patterned third photoresist layer (not shown) on the surface of the substrate 200, and the third photoresist layer exposes the side wall surface and the top surface of the base region 202 surrounded by the annular isolation structure 207; using the third photoresist layer as a mask, performing N-type ion implantation on the side wall and the top of the base region 202 to form the emitter region 210 on the surface of the base region 202; after the emitter region is formed, removing the third photoresist layer.

[0076] Please refer to Figure 11 After forming the emitter region 210, it also includes: forming a collector 211 on the collector region 201, the collector 211 has the same doping type as the collector region 201, and the doping concentration of the collector 211 is greater than the doping concentration of the collector region 201; forming a base 212 on the base region 202, the base 212 has the same doping type as the base region 202, and the doping concentration of the base 212 is greater than the doping concentration of the base region 202.

[0077] The collector electrode 211 serves as the lead-out terminal of the collector region 201, and the collector region 201 is electrically connected to the subsequently formed metal silicide layer through the collector electrode 211, and then electrically connected to other semiconductor devices or external circuits; the base electrode 212 serves as the lead-out terminal of the base region 202, and the base region 202 is electrically connected to the subsequently formed metal silicide layer through the base electrode 212, and then electrically connected to other semiconductor devices or external circuits.

[0078] In this embodiment, the collector electrode 211 is specifically formed in the collector region 201 between the first isolation structure 208 and the second isolation structure 209. The method for forming the collector electrode 211 includes: forming a patterned fourth photoresist layer (not shown) on the surface of the substrate 200 to expose the surface of the collector region 201 located between the first isolation structure 218 and the second isolation structure 219; performing N-type ion implantation on the exposed collector region 201 using the patterned fourth photoresist layer as a mask to form the collector electrode 211; and removing the patterned fourth photoresist layer after forming the collector electrode 211.

[0079] In this embodiment, the base 212 is specifically formed between the first isolation structure 208 and the annular isolation structure 207. The method for forming the base 211 includes: forming a patterned fifth photoresist layer (not shown) on the surface of the substrate 200 to expose the base region 202 located between the first isolation structure 208 and the annular isolation structure 207; using the patterned fifth photoresist layer as a mask, performing P-type ion implantation on the exposed base region 202 to form the base 212; after forming the base, removing the patterned fifth photoresist layer.

[0080] Correspondingly, in an embodiment of the present invention, a semiconductor structure is also provided. Please continue to refer to Figure 11 , comprising: a substrate 200; a collector region 201 located on the substrate 200; a base region 202 located on the collector region 201, the doping type of the base region 202 being opposite to the doping type of the collector region 201, and the bottom of the base region 202 being higher than the bottom of the collector region 201; a transition region 203 located within the base region 202, the doping type of the transition region 203 being opposite to the doping type of the base region 202, the bottom of the transition region 203 being higher than the bottom of the base region 202, and the top of the transition region 203 being lower than the top of the base region 202; an emitter region 210 located on the base region 202, the doping type of the emitter region 210 being opposite to the doping type of the base region 202, and the bottom of the emitter region 210 being higher than the bottom of the base region 202.

[0081] In this embodiment, it also includes: a collector 211 located on the collector region 201, the collector 211 has the same doping type as the collector region 201, and the doping concentration of the collector 211 is greater than the doping concentration of the collector region 201; a base 212 located on the base region 202, the base 212 has the same doping type as the base region 202, and the doping concentration of the base 212 is greater than the doping concentration of the base region 202.

[0082] In this embodiment, the device further includes: an annular isolation structure 207 located on the base region 202 , the annular isolation structure 207 surrounds the emitter region 210 and a portion of the base region 202 , and the bottom of the annular isolation structure 207 is higher than the bottom of the base region 202 .

[0083] In this embodiment, it also includes: a first isolation structure 208 located on the base region 202 and the collector region 201, the first isolation structure 208 surrounds the base region 202, and the bottom of the first isolation structure 208 is higher than the bottom of the base region 202; a second isolation structure 209 located on the substrate 200 and the collector region 201, the second isolation structure 209 surrounds the collector region 201, and the bottom of the second isolation structure 209 is higher than the bottom of the collector region 201.

[0084] In this embodiment, the collector region 201 is doped with N-type doping, the base region 202 is doped with P-type doping, the emitter region 210 is doped with N-type doping, and the transition region 203 is doped with N-type doping. In other embodiments, the collector region is doped with P-type doping, the base region is doped with N-type doping, the emitter region is doped with P-type doping, and the transition region is doped with P-type doping.

[0085] In this embodiment, the N-type doping doping ions are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the P-type doping doping ions are P-type ions, and the P-type ions include: boron ions or indium ions.

[0086] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A semiconductor structure, characterized in that include: substrate; a collector region located on the substrate; a base region located on the collector region, wherein the doping type of the base region is opposite to that of the collector region, the bottom of the base region is higher than the bottom of the collector region, and the base region is formed by ion implantation into the collector region; a transition region located in the base region, wherein the doping type of the transition region is opposite to that of the base region, and the bottom of the transition region is higher than the bottom of the base region, and the top of the transition region is lower than the top of the base region; An emitter region located on the base region, wherein the doping type of the emitter region is opposite to that of the base region, and the bottom of the emitter region is higher than the bottom of the base region, and the emitter region is formed by ion implantation into the base region; wherein, The collector region surrounds the base region located at the top and bottom of the transition region, isolating current from directly flowing from the base region to the substrate; The distance between the top of the transition region and the top of the base region is smaller than the distance between the top of the collector region and the top of the base region below the transition region. After the majority carriers of the emitter region are injected into the base region, in the process of the majority carriers of the emitter region crossing the base region to reach the transition region, the recombination loss of the majority carriers of the emitter region and the majority carriers in the base region is reduced, and the number of majority carriers of the emitter region reaching the transition region is increased. When power is turned on, a circuit is formed between the transition region and the collector region, and the majority carriers of the emitter region reaching the transition region are directly collected by the collector region to form a collector region current, thereby increasing the current amplification factor β.

2. The semiconductor structure according to claim 1, wherein: It also includes: a collector located on the collector region, the collector having the same doping type as the collector region, and the doping concentration of the collector being greater than the doping concentration of the collector region; and a base located on the base region, the base having the same doping type as the base region, and the doping concentration of the base being greater than the doping concentration of the base region.

3. The semiconductor structure according to claim 1, wherein: Also includes: An annular isolation structure is located on the base region, the annular isolation structure surrounds the emitter region and a portion of the base region, and the bottom of the annular isolation structure is higher than the bottom of the base region.

4. The semiconductor structure according to claim 1, wherein: Also includes: a first isolation structure located on the base region and the collector region, wherein the first isolation structure surrounds the base region and a bottom of the first isolation structure is higher than a bottom of the base region; A second isolation structure is located on the substrate and the collector region, the second isolation structure surrounds the collector region, and a bottom of the second isolation structure is higher than a bottom of the collector region.

5. The semiconductor structure according to claim 1, wherein: The doping type of the collector region is N-type doping, the doping type of the base region is P-type doping, the doping type of the emitter region is N-type doping, and the doping type of the transition region is N-type doping.

6. The semiconductor structure according to claim 1, wherein: The collector region is doped with P-type doping, the base region is doped with N-type doping, the emitter region is doped with P-type doping, and the transition region is doped with P-type doping.

7. The semiconductor structure according to claim 5 or 6, wherein: The doping ions of the N-type doping are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the doping ions of the P-type doping are P-type ions, and the P-type ions include: boron ions or indium ions.

8. A method for forming a semiconductor structure, characterized in that: include providing a substrate; forming a collector region on the substrate; forming a base region on the collector region, wherein the doping type of the base region is opposite to that of the collector region, and the bottom of the base region is higher than the bottom of the collector region, and the base region is formed by ion implantation into the collector region; forming a transition region in the base region, wherein the doping type of the transition region is opposite to that of the base region, and the bottom of the transition region is higher than the bottom of the base region, and the top of the transition region is lower than the top of the base region; An emitter region is formed on the base region, wherein the doping type of the emitter region is opposite to that of the base region, and the bottom of the emitter region is higher than the bottom of the base region, and the emitter region is formed by ion implantation into the base region; wherein, The collector region surrounds the base region located at the top and bottom of the transition region, isolating current from directly flowing from the base region to the substrate; The distance between the top of the transition region and the top of the base region is smaller than the distance between the top of the collector region and the top of the base region below the transition region. After the majority carriers of the emitter region are injected into the base region, in the process of the majority carriers of the emitter region crossing the base region to reach the transition region, the recombination loss of the majority carriers of the emitter region and the majority carriers in the base region is reduced, and the number of majority carriers of the emitter region reaching the transition region is increased. When power is turned on, a circuit is formed between the transition region and the collector region, and the majority carriers of the emitter region reaching the transition region are directly collected by the collector region to form a collector region current, thereby increasing the current amplification factor β.

9. The method for forming a semiconductor structure according to claim 8, wherein: Also includes: A collector is formed on the collector region, wherein the collector has the same doping type as the collector region and the doping concentration of the collector is greater than the doping concentration of the collector region; a base is formed on the base region, wherein the base has the same doping type as the base region and the doping concentration of the base is greater than the doping concentration of the base region.

10. The method for forming a semiconductor structure according to claim 8, wherein: Also includes: An annular isolation structure is formed on the base region, the annular isolation structure surrounds the emitter region and a portion of the base region, and the bottom of the annular isolation structure is higher than the bottom of the base region.

11. The method for forming a semiconductor structure according to claim 8, wherein: Also includes: forming a first isolation structure on the base region and the collector region, wherein the first isolation structure surrounds the base region, and a bottom of the first isolation structure is higher than a bottom of the base region; A second isolation structure is formed on the substrate and the collector region, wherein the second isolation structure surrounds the collector region and a bottom of the second isolation structure is higher than a bottom of the collector region.

12. The method for forming a semiconductor structure according to claim 8, wherein: The doping type of the collector region is N-type doping, the doping type of the base region is P-type doping, the doping type of the emitter region is N-type doping, and the doping type of the transition region is N-type doping.

13. The method for forming a semiconductor structure according to claim 8, wherein: The collector region is doped with P-type doping, the base region is doped with N-type doping, the emitter region is doped with P-type doping, and the transition region is doped with P-type doping.

14. The method for forming a semiconductor structure according to claim 12 or 13, wherein: The doping ions of the N-type doping are N-type ions, and the N-type ions include: phosphorus ions or arsenic ions; the doping ions of the P-type doping are P-type ions, and the P-type ions include: boron ions or indium ions.

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