阅读说明：本技术 隧穿场效应晶体管及其形成方法 (Tunneling field effect transistor and forming method thereof ) 是由 赵猛 于 2018-07-13 设计创作，主要内容包括：一种隧穿场效应晶体管及其形成方法,方法包括：提供半导体衬底,所述半导体衬底内具有沟道区,所述沟道区表面具有栅极结构,分别在栅极结构两侧的半导体衬底内形成第一硅化物层和第二硅化物层,第一硅化物层和第二硅化物层到栅极结构侧壁的距离大于零；在第一硅化物层和栅极结构之间形成第一掺杂区,所述第一掺杂区具有第一离子；在第二硅化物层和栅极结构之间形成第二掺杂区,所述第二掺杂区具有第二离子,所述第一离子和第二离子导电类型相反。所述方法提高了隧穿场效应晶体管的性能。(A tunneling field effect transistor and a forming method thereof are provided, the method comprises the following steps: providing a semiconductor substrate, wherein a channel region is arranged in the semiconductor substrate, the surface of the channel region is provided with a gate structure, a first silicide layer and a second silicide layer are respectively formed in the semiconductor substrate at two sides of the gate structure, and the distance from the first silicide layer to the side wall of the gate structure is greater than zero; forming a first doped region between the first silicide layer and the gate structure, the first doped region having first ions; a second doped region is formed between the second silicide layer and the gate structure, the second doped region having second ions, the first ions and the second ions being of opposite conductivity types. The method improves the performance of the tunneling field effect transistor.)

1. A method for forming a Tunneling Field Effect Transistor (TFET), comprising:

providing a semiconductor substrate, wherein a channel region is arranged in the semiconductor substrate, the surface of the channel region is provided with a gate structure, a first silicide layer and a second silicide layer are respectively formed in the semiconductor substrate at two sides of the gate structure, and the distance from the first silicide layer to the side wall of the gate structure is greater than zero;

forming a first doped region between the first silicide layer and the gate structure, the first doped region having first ions;

a second doped region is formed between the second silicide layer and the gate structure, the second doped region having second ions, the first ions and the second ions being of opposite conductivity types.

2. The method of claim 1, wherein the materials of the first and second silicide layers comprise: a metal layer or a metal silicide layer.

3. The method of forming a tunneling field effect transistor according to claim 1, wherein the method of forming the first silicide layer and the second silicide layer comprises: respectively forming a first groove and a second groove in the semiconductor substrate at two sides of the grid structure; forming the first silicide layer in the first groove; and forming the second silicide layer in the second groove.

4. The method of forming a tunneling field effect transistor according to claim 3, wherein the method of forming the first silicide layer and the second silicide layer comprises: respectively forming a first groove and a second groove in the semiconductor substrate at two sides of the grid structure; forming metal layers in the first groove and the second groove; annealing the metal layer, the semiconductor substrate at the bottom of the first groove and the semiconductor substrate at the bottom of the second groove, and forming the first silicide layer in the first groove; and forming the second silicide layer in the second groove.

5. The method as claimed in claim 1, wherein the semiconductor substrate at the bottom of the first silicide layer has a third doped region therein, and the semiconductor substrate at the bottom of the second silicide layer has a fourth doped region therein; the method for forming the first silicide layer and the second silicide layer comprises the following steps: respectively forming an initial third doping area and an initial fourth doping area in the semiconductor substrate on two sides of the grid structure, wherein the doping types of the initial third doping area and the initial fourth doping area are the same; and carrying out metal silicification on the initial third doped region and the initial fourth doped region to form a third doped region and a first silicide layer positioned on the surface of the third doped region, and to form a fourth doped region and a second silicide layer positioned on the surface of the fourth doped region.

6. The method of forming a tunneling field effect transistor according to claim 1, wherein the method of forming the first silicide layer and the second silicide layer further comprises: respectively forming an initial third doping area and an initial fourth doping area in the semiconductor substrate on two sides of the grid structure, wherein the doping types of the initial third doping area and the initial fourth doping area are the same; and carrying out metal silicification treatment on the initial third doped region and the initial fourth doped region, so that the initial third doped region is formed into a first silicide layer, and the initial fourth doped region is formed into a second silicide layer.

7. The method as claimed in claim 3, 5 or 6, wherein the bottom surface of the first silicide layer is lower than the bottom surface of the first doped region, or the bottom surface of the first silicide layer is flush with the bottom surface of the first doped region.

8. The method as claimed in claim 3, 5 or 6, wherein the bottom surface of the second silicide layer is lower than the bottom surface of the second doped region, or the bottom surface of the second silicide layer is flush with the bottom surface of the second doped region.

9. The method of claim 1, wherein the method of forming the first and second doped regions comprises: forming side walls on two sides of the grid structure; after the side wall is formed, forming a first silicide layer and a second silicide layer in the semiconductor substrate on the two sides of the grid structure and the side wall; after the first silicide layer and the second silicide layer are formed, removing the side wall; after removing the side wall, performing first ion implantation on the semiconductor substrate on one side of the gate structure to form the first doped region; and after the first doped region is formed, performing second ion implantation on the semiconductor substrate on the other side of the grid structure to form the second doped region.

10. The method for forming the semiconductor device according to claim 9, wherein the thickness of the side wall is 10nm to 16 nm.

11. The method as claimed in claim 1, wherein the first doped region further has a third dopant ion, and when the conductivity type of the first ion is P-type, the third dopant ion is germanium ion, tin ion, antimony ion or carbon ion; when the conductivity type of the first ions is N-type, the third doping ions are carbon ions, nitrogen ions or germanium ions.

12. The method of claim 1, wherein the second doped region further comprises fourth dopant ions; when the conductivity type of the second ions is N type, the fourth doped ions are carbon ions, nitrogen ions or germanium ions; when the conductivity type of the second ions is P-type, the fourth doped ions include: germanium ions, tin ions, antimony ions or carbon ions.

13. The method of claim 11, wherein the first doped region is formed by a first ion implantation process, and the parameters of the first ion implantation process include: the implanted ions comprise boron ions and germanium ions or BF^2-Ions and germanium ions, boron ions having an energy range of 05 KeV-2 KeV, the energy range of germanium ions is 10 KeV-50 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²(ii) a Or BF^2-The ion energy range is 0.5 KeV-2 KeV, and the germanium ion energy range is 10 KeV-50 KeV.

14. The method of claim 12, wherein the second doped region is formed by a second ion implantation process, and the parameters of the second ion implantation process include: the implanted ions comprise phosphorus ions and carbon ions, the energy range of the phosphorus ions is 2 KeV-10 KeV, the energy range of the carbon ions is 3 KeV-15 KeV, and the dosage range is 3E14atom/cm 2-6E 14atom/cm 2.

15. The method of forming a tunneling field effect transistor according to claim 1, further comprising: after a first doped region and a second doped region are formed, a dielectric layer is formed on the semiconductor substrate and covers the side wall of the pseudo gate structure; removing the pseudo gate structure, and forming a gate opening in the dielectric layer; and forming a gate structure in the gate opening.

16. The method of claim 15, wherein after forming the first doped region and the second doped region and before forming the dielectric layer, further comprising: and forming protective side walls on two sides of the pseudo gate structure, wherein the protective side walls cover the top surfaces of the first doped region and the second doped region, the protective side walls cover the side walls of the pseudo gate structure, and the dielectric layer covers the side walls of the protective side walls.

17. The method for forming the semiconductor device according to claim 16, wherein the thickness of the protective sidewall spacer is 7nm to 12 nm.

18. The method of claim 16, wherein the material of the protective sidewall comprises: silicon nitride with 0.1-1% of hydrogen atom percentage.

19. The method as claimed in claim 14, further comprising implanting third ions into the semiconductor substrate exposed by the gate opening after forming the gate opening and before forming the gate structure, wherein the implanted ions are fifth doped ions.

20. A tunneling field effect transistor, comprising:

the semiconductor device comprises a semiconductor substrate, a gate electrode and a gate electrode, wherein a channel region is arranged in the semiconductor substrate, and the surface of the channel region is provided with a gate structure;

the first silicide layer and the second silicide layer are positioned in the semiconductor substrate on two sides of the grid structure, and the distance from the first silicide layer to the side wall of the grid structure is greater than zero;

forming a first doped region between the first silicide layer and the gate structure, the first doped region having first ions;

and forming a second doped region between the second silicide layer and the gate structure, wherein the second doped region has second ions, and the first ions and the second ions have opposite conduction types.

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a tunneling field effect transistor and a forming method thereof.

Background

With the rapid development of semiconductor manufacturing technology, semiconductor devices are being developed toward higher element density and higher integration, and the feature size of CMOS devices as semiconductor core devices is being reduced. Consequently, the adverse effects of short channel effects and the like of the device are also getting worse. The leakage current of the off state of the device is continuously increased due to the effects of reduction of a leakage induced barrier, band-to-band tunneling and the like, and meanwhile, the limitation that the subthreshold slope of the traditional MOSFET receives thermoelectric force cannot be synchronously reduced along with the reduction of the size of the device, so that the power consumption of the device is increased. Power consumption problems have become the most severe problem today limiting the scaling down of devices.

In order to apply the device to the field of ultra-low voltage and low power consumption, a device structure and a process preparation method for obtaining an ultra-steep sub-threshold slope by adopting a novel conduction mechanism have become the focus of attention of people under small-size devices. Because the source-drain doping types of Tunneling Field-Effect transistors (TFETs) are opposite, the conduction is realized by band-to-band Tunneling of P-I-N junctions with reverse bias controlled by a grid electrode, the limitation of the sub-threshold slope 60Mv/dec of the traditional MOSFET can be broken through, the leakage current is very small, the short channel Effect is avoided, the sub-threshold swing can be smaller than 60mV/decade, the lower working voltage can be used, and the Tunneling Field-Effect transistors are considered as inheritors of the CMOS transistors.

The TFET has many excellent characteristics such as low leakage current, low threshold slope, low operating voltage and low power consumption, but the TFET has the problems of small on-state current and poor driving capability.

Disclosure of Invention

The invention provides a tunneling field effect transistor and a forming method thereof, which are used for improving the performance of the tunneling field effect transistor.

To solve the above technical problem, the present invention provides a method for forming a tunneling field effect transistor, including: providing a semiconductor substrate, wherein a channel region is arranged in the semiconductor substrate, the surface of the channel region is provided with a gate structure, a first silicide layer and a second silicide layer are respectively formed in the semiconductor substrate at two sides of the gate structure, and the distance from the first silicide layer to the side wall of the gate structure is greater than zero; forming a first doped region between the first silicide layer and the gate structure, the first doped region having first ions; a second doped region is formed between the second silicide layer and the gate structure, the second doped region having second ions, the first ions and the second ions being of opposite conductivity types.

Optionally, the materials of the first silicide layer and the second silicide layer include: a metal layer or a metal silicide layer.

Optionally, the method for forming the first silicide layer and the second silicide layer includes: respectively forming a first groove and a second groove in the semiconductor substrate at two sides of the grid structure; forming the first silicide layer in the first groove; and forming the second silicide layer in the second groove.

Optionally, the method for forming the first silicide layer and the second silicide layer includes: respectively forming a first groove and a second groove in the semiconductor substrate at two sides of the grid structure; forming metal layers in the first groove and the second groove; annealing the metal layer, the semiconductor substrate at the bottom of the first groove and the semiconductor substrate at the bottom of the second groove, and forming the first silicide layer in the first groove; and forming the second silicide layer in the second groove.

Optionally, a third doped region is arranged in the semiconductor substrate at the bottom of the first silicide layer, and a fourth doped region is arranged in the semiconductor substrate at the bottom of the second silicide layer; the method for forming the first silicide layer and the second silicide layer comprises the following steps: respectively forming an initial third doping area and an initial fourth doping area in the semiconductor substrate on two sides of the grid structure, wherein the doping types of the initial third doping area and the initial fourth doping area are the same; and carrying out metal silicification on the initial third doped region and the initial fourth doped region to form a third doped region and a first silicide layer positioned on the surface of the third doped region, and to form a fourth doped region and a second silicide layer positioned on the surface of the fourth doped region.

Optionally, the method for forming the first silicide layer and the second silicide layer further includes: respectively forming an initial third doping area and an initial fourth doping area in the semiconductor substrate on two sides of the grid structure, wherein the doping types of the initial third doping area and the initial fourth doping area are the same; and carrying out metal silicification treatment on the initial third doped region and the initial fourth doped region, so that the initial third doped region is formed into a first silicide layer, and the initial fourth doped region is formed into a second silicide layer.

Optionally, the bottom surface of the first silicide layer is lower than the bottom surface of the first doped region, or the bottom surface of the first silicide layer is flush with the bottom surface of the first doped region.

Optionally, the bottom surface of the second silicide layer is lower than the bottom surface of the second doped region, or the bottom surface of the second silicide layer is flush with the bottom surface of the second doped region.

Optionally, the method for forming the first doped region and the second doped region includes: forming side walls on two sides of the grid structure; after the side wall is formed, forming a first silicide layer and a second silicide layer in the semiconductor substrate on the two sides of the grid structure and the side wall; after the first silicide layer and the second silicide layer are formed, removing the side wall; after removing the side wall, performing first ion implantation on the semiconductor substrate on one side of the gate structure to form the first doped region; and after the first doped region is formed, performing second ion implantation on the semiconductor substrate on the other side of the grid structure to form the second doped region.

Optionally, the thickness of the side wall is 10nm to 16 nm.

Optionally, the first doping region further has third doping ions, and when the conductivity type of the first ions is P-type, the third doping ions are germanium ions, tin ions, antimony ions or carbon ions; when the conductivity type of the first ions is N-type, the third doping ions are carbon ions, nitrogen ions or germanium ions.

Optionally, the second doped region further has fourth doped ions; when the conductivity type of the second ions is N type, the fourth doped ions are carbon ions, nitrogen ions or germanium ions; when the conductivity type of the second ions is P-type, the fourth doped ions include: germanium ions, tin ions, antimony ions or carbon ions.

Optionally, a forming process of the first doped region is a first ion implantation process, and parameters of the first ion implantation process include: the implanted ions comprise boron ions and germanium ions or BF^2-Ions and germanium ions, wherein the energy range of the boron ions is 0.5 KeV-2 KeV, the energy range of the germanium ions is 10 KeV-50 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²(ii) a Or BF^2-The ion energy range is 0.5 KeV-2 KeV, and the germanium ion energy range is 10 KeV-50 KeV.

Optionally, a forming process of the second doped region is a second ion implantation process, and parameters of the second ion implantation process include: the implanted ions comprise phosphorus ions and carbon ions, the energy range of the phosphorus ions is 2 KeV-10 KeV, the energy range of the carbon ions is 3 KeV-15 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²。

Optionally, the method further comprises: after a first doped region and a second doped region are formed, a dielectric layer is formed on the semiconductor substrate and covers the side wall of the pseudo gate structure; removing the pseudo gate structure, and forming a gate opening in the dielectric layer; and forming a gate structure in the gate opening.

Optionally, after forming the first doped region and the second doped region, before forming the dielectric layer, the method further includes: and forming protective side walls on two sides of the pseudo gate structure, wherein the protective side walls cover the top surfaces of the first doped region and the second doped region, the protective side walls cover the side walls of the pseudo gate structure, and the dielectric layer covers the side walls of the protective side walls.

Optionally, the thickness of the protective side wall is 7nm to 12 nm.

Optionally, the material of the protective sidewall includes: silicon nitride with 0.1-1% of hydrogen atom percentage.

Optionally, after the gate opening is formed and before the gate structure is formed, third ion implantation is performed on the semiconductor substrate exposed by the gate opening, where the implanted ions are fifth doped ions.

Correspondingly, the invention also provides a tunneling field effect transistor, which comprises: the semiconductor device comprises a semiconductor substrate, a gate electrode and a gate electrode, wherein a channel region is arranged in the semiconductor substrate, and the surface of the channel region is provided with a gate structure; the first silicide layer and the second silicide layer are positioned in the semiconductor substrate on two sides of the grid structure, and the distance from the first silicide layer to the side wall of the grid structure is greater than zero; forming a first doped region between the first silicide layer and the gate structure, the first doped region having first ions; and forming a second doped region between the second silicide layer and the gate structure, wherein the second doped region has second ions, and the first ions and the second ions have opposite conduction types.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:

in the forming method of the tunneling field effect transistor, the conductivity types of the doped ions of the first doped region and the second doped region are different, and the first doped region, the second doped region and the channel region form the tunneling field effect transistor together. The first silicide layer is connected with the first doping region, and the second silicide layer is connected with the second doping region, so that current carriers tunneling through the channel region can be led out as soon as possible due to good conductivity of the first silicide layer and the second silicide layer, and the current of the channel region is increased; meanwhile, the first silicide layer and the second silicide layer are subsequently contacted with the plug, so that the contact resistance between the first silicide layer and the plug and between the second silicide layer and the plug are reduced, the on-state current is further increased, and the performance of the tunneling field effect transistor is improved.

Furthermore, the protective side wall is made of silicon nitride with the hydrogen atom percentage of 0.1% -1%, and hydrogen atoms react with impurity ions in the forming process of the first doping area and the second doping area, so that the doping quality of the first doping area and the second doping area is improved, the tunneling current is improved, and the performance of the tunneling field effect transistor is optimized.

Drawings

FIG. 1 is a schematic diagram of a tunneling field effect transistor;

fig. 2 to 8 are schematic structural diagrams illustrating a process of forming a tunnel field effect transistor according to an embodiment of the present invention.

Detailed Description

As mentioned in the background, the performance of the prior art tunneling field effect transistor is poor.

Fig. 1 is a schematic structural diagram of a tunneling field effect transistor.

A tunneling field effect transistor, referring to fig. 1, comprising: the semiconductor device comprises a semiconductor substrate 100, a channel region 110 located on the surface of the semiconductor substrate 100, a gate structure 120 located on the surface of the channel region, and a third doped region 131 and a fourth doped region 132 located in the semiconductor substrate 100 at two sides of the gate structure 120.

The third doped region 131 and the fourth doped region 132 are respectively a source terminal and a drain terminal of the tunneling field effect transistor, one of which is a P region (hole doped), the other of which is an N region (electron doped), and the middle channel region 110 is an intrinsic material. Under the driving voltage, holes can tunnel from the P region to the N region to form tunneling current, the tunneling field effect transistor has the advantages of small leakage current, small sub-threshold slope and the like, but the tunneling field effect transistor generates current by utilizing the tunneling effect, so that the on-state current is small, and the performance of the tunneling field effect transistor is poor.

In order to solve the above problems, the present invention provides a method for forming a tunneling field effect transistor, wherein a first silicide layer and a second silicide layer are respectively formed on two sides of a source-drain doped region of the tunneling field effect transistor, the first silicide layer is connected with one source-drain doped region, and the second silicide layer is connected with the other source-drain doped region; the first silicide layer and the second silicide layer have good conductivity, so that current carriers in the tunneling channel region can be led out as soon as possible, the current of the channel region is increased, and the performance of the tunneling field effect transistor is improved.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 2 to 8 are schematic structural diagrams illustrating a process of forming a tunnel field effect transistor according to an embodiment of the present invention.

Referring to fig. 2, a semiconductor substrate 200 is provided.

In this embodiment, the tunneling field effect transistor is a fin field effect transistor, and the semiconductor substrate 200 has a fin portion 210 thereon. In other embodiments, the tunneling field effect transistor is a planar field effect transistor, and the semiconductor substrate 200 is a planar structure.

In this embodiment, the material of the semiconductor substrate 200 is monocrystalline silicon. The semiconductor substrate 200 may also be polysilicon or amorphous silicon. The material of the semiconductor substrate 200 may also be germanium, silicon germanium, gallium arsenide, or other semiconductor materials. The semiconductor substrate 200 can also be a semiconductor-on-insulator structure including an insulator and a semiconductor material layer on the insulator, wherein the semiconductor material layer includes a semiconductor material such as silicon, germanium, silicon germanium, gallium arsenide, or indium gallium arsenide.

In this embodiment, the fin 210 is formed by patterning the semiconductor substrate 200. In other embodiments, it may be: a fin material layer is formed on the semiconductor substrate and then patterned to form a fin 210.

In this embodiment, the material of the fin portion 210 is monocrystalline silicon. In other embodiments, the material of the fin 210 is single crystal silicon germanium or other semiconductor materials.

In this embodiment, the semiconductor substrate 200 further has an isolation layer thereon, the isolation layer covers a portion of the sidewall surface of the fin, and the surface of the isolation layer is lower than the top surface of the fin 210. The material of the isolation layer comprises silicon oxide.

In this embodiment, the surface of fin 210 has a protection layer (not shown) that protects fin 210 during subsequent ion implantation into fin 210.

The material of the protective layer includes silicon nitride, silicon carbide nitride, silicon boride nitride, silicon oxycarbide or silicon oxynitride, and in this embodiment, the material of the protective layer is silicon oxide.

The semiconductor substrate 200 has a channel region therein, and the surface of the channel region has a gate structure.

In this embodiment, the gate structure is a dummy gate structure.

In other embodiments, the gate structure includes: the gate dielectric layer and a gate electrode layer positioned on the surface of the gate dielectric layer.

With continued reference to fig. 2, a dummy gate structure is formed on the semiconductor substrate 200 to cross the fin 210, and the channel region is located in the semiconductor substrate 200 covered by the dummy gate structure.

The dummy gate structure provides space for the subsequent formation of a gate structure.

In this embodiment, the dummy gate structure includes a dummy gate layer 220 and a dummy gate protection layer 221, and the dummy gate layer 220 covers a portion of the sidewall and the top surface of the fin portion 210.

The dummy gate layer 220 is made of polysilicon, and the dummy gate protection layer 221 is made of silicon nitride.

In other embodiments, the dummy gate structure includes a dummy gate dielectric layer, a dummy gate layer on a surface of the dummy gate dielectric layer, and a dummy gate protection layer on a surface of the dummy gate layer.

Referring to fig. 3, a first silicide layer 241 and a second silicide layer 242 are formed in the semiconductor substrate at both sides of the dummy gate structure, respectively, and the distance from the first silicide layer 241 and the second silicide layer 242 to the sidewall of the dummy gate structure is greater than zero.

The materials of the first silicide layer 241 and the second silicide layer 242 include: a metal layer or a metal silicide layer.

In this embodiment, the material of the first silicide layer 241 and the second silicide layer 242 is a metal silicide layer.

The method for forming the first silicide layer 241 and the second silicide layer 242 includes: respectively forming an initial third doping region and an initial fourth doping region in the semiconductor substrate 200 at two sides of the dummy gate structure, wherein the doping types of the initial third doping region and the initial fourth doping region are the same; the initial third doped region and the initial fourth doped region are metal silicided such that the initial third doped region is formed as a first silicide layer 241 and the initial fourth doped region is formed as a second silicide layer 242.

The bottom surface of the first silicide layer 241 is lower than the bottom surface of the subsequently formed first doped region, or the bottom surface of the first silicide layer 241 is flush with the bottom surface of the first doped region.

The bottom surface of the second silicide layer 242 is lower than the bottom surface of the second doped region to be formed later, or the bottom surface of the second silicide layer 242 is flush with the bottom surface of the second doped region.

In this embodiment, the bottom surface of the first silicide layer 241 is flush with the bottom surface of the first doped region, and the bottom surface of the second silicide layer 242 is flush with the bottom surface of the second doped region.

The bottom surface of the first silicide layer 241 is flush with the bottom surface of the first doped region, the bottom surface of the second silicide layer 242 is flush with the bottom surface of the second doped region, the first doped region and the second doped region are source-drain doped regions of the tunneling field effect transistor formed subsequently, and therefore the contact area between the first silicide layer 241 and the second silicide layer 242 and the source-drain doped regions of the tunneling field effect transistor formed subsequently is large, current of the tunneling field effect transistor can be rapidly led out, and on-state current of the tunneling field effect transistor is improved.

In one embodiment, the semiconductor substrate 200 at the bottom of the first silicide layer 241 has a third doped region therein, and the semiconductor substrate 200 at the bottom of the second silicide layer 242 has a fourth doped region therein; the method for forming the first silicide layer 241 and the second silicide layer 242 includes: respectively forming an initial third doping region and an initial fourth doping region in the semiconductor substrate 200 at two sides of the dummy gate structure, wherein the doping types of the initial third doping region and the initial fourth doping region are the same; and performing metal silicidation on the initial third doped region and the initial fourth doped region to form a third doped region and a first silicide layer 241 on the surface of the third doped region, and to form a fourth doped region and a second silicide layer 242 on the surface of the fourth doped region.

In an embodiment, the material of the first silicide layer 241 and the second silicide layer 242 is a metal layer, and the method for forming the first silicide layer 241 and the second silicide layer 242 includes: respectively forming a first groove and a second groove in the semiconductor substrate at two sides of the grid structure; forming the first silicide layer 241 in the first groove; the second silicide layer 242 is formed within the second recess.

In an embodiment, the material of the first silicide layer 241 and the second silicide layer 242 is a metal silicide layer, and the forming method of the first silicide layer 241 and the second silicide layer 242 includes: respectively forming a first groove and a second groove in the semiconductor substrate 200 at two sides of the gate structure; forming metal layers in the first groove and the second groove; annealing the metal layer, the semiconductor substrate at the bottom of the first groove and the semiconductor substrate at the bottom of the second groove, and forming the first silicide layer 241 in the first groove; the second silicide layer 242 is formed within the second recess.

In this embodiment, before forming the first silicide layer 241 and the second silicide layer 242, forming a sidewall spacer 230 on a sidewall of the dummy gate structure, where the sidewall spacer 230 covers sidewall surfaces of the dummy gate layer 220 and the dummy gate protection layer 221.

The sidewall spacers 230 define the positions of the first doped region and the second doped region to be formed later.

The forming method of the side wall comprises the following steps: forming a side wall material layer (not shown) on the semiconductor substrate 200, the fin portion 210 and the dummy gate structure; and etching back the side wall material layer until the top surfaces of the pseudo gate protection layer 221 and the fin portion 210 are exposed, and forming the side wall 230 on the side wall of the pseudo gate structure.

The material of the sidewall spacers 230 includes: silicon oxide, silicon nitride, silicon carbonitride, silicon boronitride, silicon oxycarbonitride or silicon oxynitride.

In this embodiment, the sidewall spacers 230 are made of silicon nitride.

The thickness of the side wall 230 is 10nm to 16 nm.

In this embodiment, the method for forming the initial third doped region and the initial fourth doped region includes: and performing ion implantation on the dummy gate structure and the fin portions 210 on the two sides of the side wall to form an initial third doped region and an initial fourth doped region.

When the gate structure is used for forming an N-type device, the dopant ions of the initial third and fourth doped regions are N-type ions, and the N-type ions include: phosphorus ions, arsenic ions or antimony ions; the material of the initial third doped region and the initial fourth doped region comprises silicon germanium doped with N-type ions.

When the gate structure is used for forming a P-type device, the dopant ions of the initial third and fourth doped regions are P-type ions, and the P-type ions include: boron ion, BF^2-Ions or indium ions; the material of the initial third doped region and the initial fourth doped region comprises silicon doped with P-type ions.

In this embodiment, the gate structure is used to form a P-type device, and the material of the initial third doped region and the initial fourth doped region includes silicon doped with boron ions.

In other embodiments, the gate structure is used to form an N-type device, and the material of the initial third doped region and the initial fourth doped region comprises silicon germanium doped with phosphorous ions.

The method for metal silicification processing comprises the following steps: forming a metal layer (not shown) on the surfaces of the initial third doped region and the initial fourth doped region; after the metal layer is formed, a first annealing process is performed on the metal layer, the initial third doped region and the initial fourth doped region, so that the initial third doped region is formed as a first silicide layer 241, and the initial fourth doped region is formed as a second silicide layer 242.

The material of the metal layer comprises: ti, Co or Ni.

The process of forming the metal layer is a deposition process, such as a sputtering process.

The first annealing process includes laser annealing or spike annealing.

The benefits of using laser annealing or spike annealing for the first annealing process include: the temperature rise process of laser annealing and spike annealing is fast, the ions in the doped region of the tunneling field effect transistor are prevented from being diffused greatly in the temperature rise process, and the stability of the doped region is improved.

After forming the first silicide layer 241 and the second silicide layer 242, forming a first doped region between the first silicide layer 241 and the gate structure, the first doped region having first ions; a second doped region is formed between the second silicide layer 242 and the gate structure, the second doped region having second ions, the first and second ions being of opposite conductivity types. Please refer to fig. 4 to 5.

Referring to fig. 4, after forming the first silicide layer 241 and the second silicide layer 242, the sidewall spacers 230 are removed; after removing the sidewall spacers 230, a first ion implantation is performed on the fin portion 210 at one side of the dummy gate structure to form a first doped region 251.

The method for forming the first doped region 251 includes: after removing the spacers 230, forming a first mask layer (not shown) on the surfaces of the dummy gate structure and the second silicide layer 242; after the first mask layer is formed, ion implantation is performed on the first silicide layer 241 and the fin portion 210, and the first doping layer 251 is formed between the first silicide layer 241 and the channel region.

The material of the first mask layer comprises photoresist.

The first doping region 251 is located between the first silicide layer 241 and the channel region, and is connected to the first silicide layer 241 and the channel region.

The first doped region 251 and the second doped region 252 formed subsequently have different conductivity types of doped ions, which together form a P region and an N region of the tunneling field effect transistor, and provide tunneling holes and electrons for forming the tunneling field effect transistor.

The first doped region 251 has first ions, and the second doped region 252 has second ions, the first ions being of a different conductivity type than the second ions.

When the conductivity type of the first ions is N-type and the conductivity type of the second ions is P-type, the first ions include: including phosphorus, arsenic or antimony ions; the second ions include: boron ion, BF^2-Ions or indium ions

When the conductivity type of the first ions is P-type and the conductivity type of the second ions is N-type, the first ions include: boron ion, BF^2-Ion orIndium ions; the second ions include: including phosphorus, arsenic or antimony ions.

The first doping region is also provided with third doping ions, and when the conductivity type of the first ions is P type, the third doping ions are germanium ions, tin ions, antimony ions or carbon ions; when the conductivity type of the first ions is N-type, the third doping ions are carbon ions, nitrogen ions or germanium ions.

The third doping ions can control the first ions to diffuse into the nearby channel region, and the influence of the third doping ions on the channel region is reduced.

In this embodiment, the conductivity type of the first ions is N-type, and the conductivity type of the second ions is P-type.

In this embodiment, the parameters of the first ion implantation include: the ions implanted by the first ion implantation comprise boron ions or germanium ions, the energy range of the boron ions is 0.5 KeV-2 KeV, the energy range of the germanium ions is 10 KeV-50 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²The inclination angle is 10-35 degrees; the inclination angle is an included angle between the injection direction and a normal line of a plane where the semiconductor substrate is located.

In one embodiment, the parameters of the first ion implantation include: the first ion implanted ions comprise BF^2-Ions or germanium ions, BF^2-The ion energy range is 0.5 KeV-2 KeV, the germanium ion energy range is 10 KeV-50 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²The inclination angle is 10-35 degrees; the inclination angle is an included angle between the injection direction and a normal line of a plane where the semiconductor substrate is located.

In other embodiments, the conductivity type of the first ions is P-type, and the conductivity type of the second ions is N-type.

Referring to fig. 5, after the first doped region 251 is formed, a second ion implantation is performed on the fin portion 210 on the other side of the dummy gate structure to form a second doped region 252.

After the first doping region 251 is formed and before the second doping region 252 is formed, the method further includes: and removing the first mask layer, wherein the process for removing the first mask layer is an ashing process.

The method for forming the second doped region 252 includes: forming a second mask layer (not shown) on the dummy gate structure, the first doping layer 251 and the first silicide layer 241; after forming the second mask layer, ion implantation is performed on the second silicide layer 242 and the fin portion 210, and the first doping layer 252 is formed between the second silicide layer 242 and the channel region.

The second doped region 252 is located between the second silicide layer 242 and the channel region, and is connected to the second silicide layer 242 and the channel region.

The second doped region is also provided with fourth doped ions; when the conductivity type of the second ions is N type, the fourth doped ions are carbon ions, nitrogen ions or germanium ions; when the conductivity type of the second ions is P-type, the fourth doped ions include: germanium ions, tin ions, antimony ions or carbon ions.

The fourth doping ions can control the diffusion of the second ions and reduce the influence of the second ions on the channel region.

In this embodiment, the conductivity type of the first ions is N-type, and the conductivity type of the second ions is P-type.

In this embodiment, the parameters of the second ion implantation include: the ions implanted by the second ion comprise phosphorus ions and carbon ions, the energy range of the phosphorus ions is 2 KeV-10 KeV, the energy range of the carbon ions is 3 KeV-15 KeV, and the dosage range is 3E14atom/cm²～6E14atom/cm²The inclination angle is 10-35 degrees; the inclination angle is an included angle between the injection direction and a normal line of a plane where the semiconductor substrate is located. In other embodiments, the conductivity type of the first ions is P-type, and the conductivity type of the second ions is N-type.

The first doped region and the second doped region have different conductivity types of doped ions, and the first doped region, the second doped region and the channel region form a tunneling field effect transistor together. The first silicide layer is connected with the first doping region, and the second silicide layer is connected with the second doping region, so that current carriers tunneling through the channel region can be led out as soon as possible due to good conductivity of the first silicide layer and the second silicide layer, and the current of the channel region is increased; meanwhile, the first silicide layer and the second silicide layer are subsequently contacted with the plug, so that the contact resistance between the first silicide layer and the plug and between the second silicide layer and the plug are reduced, the on-state current is further increased, and the performance of the tunneling field effect transistor is improved.

In one embodiment, the first silicide layer bottom has a third doped region, and the second silicide layer bottom has a fourth doped region; the ion doping concentration of the third doping region and the fourth doping region is high, the contact resistance between the first silicide layer and the plug formed subsequently and the second silicide layer is small, the ion types of the first doping region 251 and the second doping region 252 are opposite, and the third doping region, the fourth doping region, the first doping region 251, the second doping region 252 and the channel region together form a tunneling field effect transistor which is of a P-N-I-P type or an N-P-I-N-N type.

In this embodiment, after the first doped region 251 and the second doped region 252 are formed, a second annealing process is performed on the first doped region 251 and the second doped region 252, where the second annealing process includes laser annealing or spike annealing.

The second annealing process is used to activate the dopant ions within the first and second doped regions 251 and 252.

The benefits of using laser annealing or spike annealing for the second annealing process include: the temperature rise process of laser annealing and spike annealing is fast, the ions in the doped region of the tunneling field effect transistor are prevented from being diffused greatly in the temperature rise process, and the stability of the doped region is improved.

In other embodiments, after the first doped region 251 and the second doped region 252 are formed, the second annealing process is not performed, and the doped ions in the first doped region 251 and the second doped region 252 are activated during a subsequent thermal process such as forming a gate dielectric layer.

Referring to fig. 6, after the first doped region 251 and the second doped region 252 are formed, a dielectric layer 270 is formed on the semiconductor substrate 200 and the fin 210, and the dielectric layer 270 covers sidewalls of the dummy gate structure.

In this embodiment, after forming the first doped region 251 and the second doped region 252, and before forming the dielectric layer 270, the method further includes: forming protective side walls 260 on two sides of the pseudo gate structure, wherein the protective side walls 260 cover the top surfaces of the first doped region 251 and the second doped region 252, the protective side walls 260 cover the side walls of the pseudo gate structure, and the dielectric layer 270 covers the side walls of the protective side walls.

The protective side wall can enable the shape of a subsequently formed gate opening to be complete, and meanwhile, impurity ions of the first doping region 251, the second doping region 252 and the channel region are absorbed, so that the doping quality of the first doping region 251 and the second doping region 252 is improved, the tunneling current is improved, and the performance of the tunneling field effect transistor is improved.

The thickness of the protective side wall is 7 nm-12 nm.

The material of the protective side wall comprises: silicon nitride with 0.1-1% of hydrogen atom percentage.

The material of the protective side wall is silicon nitride with the hydrogen atom percentage of 0.1% -1%, and the hydrogen atoms can react with impurity ions of the first doping region 251, the second doping region 252 and the channel region in a thermal process, so that the influence of the impurity ions on the first doping region 251, the second doping region 252 and the channel region is reduced, and the performance of the tunneling field effect transistor is improved.

Referring to fig. 7, after the dielectric layer 270 is formed, the dummy gate structure is removed, and a gate opening 261 is formed in the dielectric layer 270.

After the gate opening 261 is formed and before the gate structure 280 is formed, third ion implantation is performed on the fin portion 210 exposed by the gate opening 270, where the implanted ions are fifth doped ions.

When the gate structure is used to form an N-type device, the fifth doping ions are N-type ions, and the fifth doping ions include: phosphorus ions, arsenic ions or antimony ions.

When the gate structure is used for forming a P-type device, the fifth doping ions are P-type ions, and the fifth doping ions include: boron ion, BF^2-Ions or indium ions.

The fin portion 210 at the bottom of the gate opening 260 is doped, that is, the channel region is doped, so that the concentration of carriers in the channel region is increased, the tunneling current is increased, and the performance of the tunneling field effect transistor is improved.

In this embodiment, the gate structure is used to form an N-type device, the fifth doping ions are P-type ions, and the fifth doping ions include: boron ion, BF^2-Ions or indium ions, the implanted ions of the third ion implantation are boron ions, and the doping concentration of the channel region after the third ion implantation is 1E18atom/cm³～5E18atom/cm³。

In other embodiments, the gate structure is used to form a P-type device, the fifth doping ions are N-type ions, and the fifth doping ions include: phosphorus ion, arsenic ion or antimony ion, the implanted ion of the third ion implantation is phosphorus ion, and the doping concentration of the channel region after the third ion implantation is 1E18atom/cm³～5E18atom/cm³。

Referring to fig. 8, after forming a gate opening 261, a gate structure 280 is formed in the gate opening 261, and a top surface of the gate structure 280 is flush with a top surface of the dielectric layer 270.

The gate structure 280 includes a gate dielectric layer and a gate layer 292 on the gate dielectric layer.

The forming process of the gate structure 280 includes: forming a gate dielectric film on the dielectric layer 270 and on the sidewall and bottom surface of the gate opening 261; forming a gate film filling the gate opening 261 on the gate dielectric film; and flattening the gate dielectric film and the gate electrode film until the top surface of the dielectric layer 270 is exposed.

Specifically, a gate dielectric layer is formed on the bottom and the side wall of the gate opening 261, and the gate dielectric layer includes an interface layer located at the bottom of the gate opening 261 and a gate dielectric body layer located on the surface of the interface layer; and forming a gate electrode layer for filling the opening on the gate dielectric layer.

The interface layer is formed at the bottom of the opening, which can avoid the adverse effect caused by the direct contact between the gate dielectric body layer and the fin portion 210.

The forming process of the interface layer is a wet oxidation process.

The interface layer is made of silicon oxide or silicon oxynitride.

When the thickness of the interface layer is too small, the interface state is not good, and when the thickness of the interface layer is too thick, the threshold voltage of the device is raised, so that the requirement of the device is not met.

In this embodiment, the material of the gate dielectric bulk layer is a high-k dielectric material (the dielectric coefficient is greater than 3.9); the high-k dielectric material comprises hafnium oxide, zirconium oxide, hafnium silicon oxide, lanthanum oxide, zirconium silicon oxide, titanium oxide, tantalum oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide or aluminum oxide.

The forming process of the gate dielectric film is one or more of a chemical vapor deposition process, a physical vapor deposition process or an atomic layer deposition process. The gate oxide film formation process in this embodiment is an atomic layer deposition process.

The material of the gate layer is metal, and the metal material comprises one or more of copper, tungsten, nickel, chromium, titanium, tantalum and aluminum.

The forming process of the grid electrode film is one or two of a physical vapor deposition process and an electroplating process. In this embodiment, the forming process of the gate film is a physical vapor deposition process.

And flattening the gate dielectric film and the gate electrode film for removing the gate dielectric film and the gate electrode film on the surface of the dielectric layer 270, and simultaneously avoiding generating leakage current on the top of the gate electrode layer due to metal material residues, thereby ensuring the stability of the electrical performance of the formed semiconductor structure.

In this embodiment, after forming the gate dielectric layer and before forming the gate layer, forming a work function layer (not shown) on the surface of the gate dielectric layer is further included.

The work function layer is used for adjusting the threshold voltage of the formed semiconductor structure.

In this embodiment, if the work function layer is used to form a PMOS transistor, the material of the work function layer is titanium oxide or titanium nitride; and if the work function layer is used for forming an NMOS transistor, the material of the work function layer is titanium or tantalum.

In this embodiment, the process of forming the work function layer is a chemical vapor deposition process.

Correspondingly, the present embodiment further provides a tunneling field effect transistor formed by the above method, and with reference to fig. 8, the method includes: the semiconductor device comprises a semiconductor substrate 200, wherein a channel region is arranged in the semiconductor substrate 200, and the surface of the channel region is provided with a gate structure 280; the first silicide layer 241 and the second silicide layer 242 are positioned in the semiconductor substrate 200 at two sides of the gate structure 280, and the distance from the first silicide layer 241 to the side wall of the gate structure 280 to the second silicide layer 242 is greater than zero; forming a first doped region 251 between the first silicide layer 241 and the gate structure 280, the first doped region 251 having first ions; a second doped region 252 is formed between the second silicide layer 242 and the gate structure 280, the second doped region 252 having second ions, the first ions and the second ions having opposite conductivity types.

The semiconductor substrate 200 refers to the content of the foregoing embodiments, and is not described in detail.

The structure and position of the gate structure 280 refer to the content of the foregoing embodiments, and are not described in detail.

The materials and positions of the first silicide layer 241 and the second silicide layer 242 refer to the contents of the foregoing embodiments, and are not described in detail.

The materials and positions of the first doped region 251 and the second doped region 252 refer to the contents of the foregoing embodiments, and are not described in detail.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.