TW201626442A - Methods for doping FinFETs - Google Patents

Abstract

The instant disclosure relates to a method for doping FinFETs. A FinFET includes a semiconductor substrate and a plurality of fins arranged on the semiconductor substrate, wherein the fins are spaced apart and parallel to each other. The method includes the following steps: forming a doped layer on an upper surface, a first sidewall, and a second sidewall of each of the fins; and directing a sputtering material into the corresponding doped layer along the normal direction of the semiconductor substrate to reduce its doping concentration.

Description

Doping method of fin field effect transistor

The invention relates to a doping method of a fin field effect transistor (FinFET), in particular to a doping method of a fin field effect transistor having a self-regulating function.

As the integrated circuit evolves from a 22nm technology node to a smaller size, the process uses FinFET (Fin Field Effect Transistor, Fin is a fin, FinFET is named according to the shape of the transistor and the fin similarity) structure. , designed to reduce channeling, has an absolute advantage in suppressing subthreshold currents and gate leakage currents. As the degree of integration increases, it will be an inevitable trend to replace traditional body devices with FinFET devices.

Referring to FIG. 1, a portion of a FinFET structure (including two cells of 100 and 200) is shown, wherein reference numeral 20 denotes a substrate, such as a germanium substrate, and reference numeral 22 denotes a shallow trench formed in or on the substrate 20. In the shallow trench isolation region, the two fins (Fin) shown are also indicated by reference numerals 124 and 224, respectively.

In a FinFET structure, doping needs to be formed in a vertical Fin. The existing doping methods in the semiconductor industry mainly include growth methods and ion implantation methods. The growth method is feasible for P-type doping, but it encounters a dilemma when forming N-type doping. In addition, the N-type dopant source is relatively common AsH ₃ , and its toxicity is very large, so it is necessary to form an N-type doping by means of arsenic ion implantation. However, in practical applications, ion implantation faces three technical problems that need to be solved, namely, uniformity, amorphization and rounding.

1, uniformity (doping conformity)

Referring to FIG. 2 and FIG. 3, since Fin is generally a vertical structure, in order to form doping in its sidewall, the direction of ion implantation must be at an angle to the length direction of Fin. Specifically, in order to achieve effective doping in the sidewalls of the Fin, the existing injection method usually adopts two injections, that is, the injection of the right side of Fin is completed according to the direction of the arrow shown in FIG. 2, and then according to FIG. The direction of the arrow shown in the arrow completes the injection on the left side of Fin. However, in such implants with dip angles, the top of Fin is subject to two ion implantations with different implant doses, which results in a severe dose doping between the top and side walls of each Fin. Evenly.

Furthermore, in order to form doping on the sidewall of Fin, the direction of ion implantation must be at an angle to the normal direction of the substrate substrate, and the doping on the top and sidewalls of Fin except 45°. The dose must be different. And as the aspect ratio of the FinFET structure increases, the ratio of the height of the Fin to the distance between the two Fins increases, the angle of the ion implantation (the angle between the injection direction and the base of the base substrate) increases. The smaller the ion, the more ions injected into the top will be more than the ions injected into the sidewall, which exacerbates the unevenness of the top and sidewall doping doses of Fin itself. At present, this non-uniformity is extremely significant, even reaching a top-to-side doping dose ratio of 20:1, idealized to be 10:1 or less. That is to say, the doping amount of the top is much larger than that of the sidewall, and this unevenness is extremely disadvantageous for the optimization of device performance.

Furthermore, if the two injection parameters are not precisely controlled to maintain consistency, the doping on the two sidewalls of Fin will be uneven, which will affect the performance of the device.

2, amorphization (Amorphization)

The existing implantation method also suffers from the problem of amorphization because the energy of the implanted ions is high, and the depth at which the ions are implanted is deep, which causes the Fin to be amorphized, and the original single crystal structure is difficult to maintain, which is The performance of the device is also extremely disadvantageous.

3, rounded (Corner erosion)

Please refer to FIG. 4, the high energy injection of the prior art will bring about the problem of amorphization. In addition, it will cause the two corners of Fin to be damaged by the impact of ions. As shown in Figure 4, Fin will be rounded after being damaged. Such rounded structure is also detrimental to device performance.

The technical problem to be solved by the present invention is to overcome the problem of poor injection uniformity caused by the ion implantation method for performing Fin doping in the prior art, in particular, the ratio of the top and sidewall doping doses of Fin is often Will exceed 10:1 defects. To this end, the present invention provides a doping method for a fin field effect transistor, which can achieve saturation of implantation through ion implantation for a long time, and add a sputtering material (such as a base element, an inert element or Group IV element) process of implantation to achieve uniform doping of Fin.

In order to achieve the above object, a preferred embodiment of the present invention adopts the following technical solution: a method for doping a fin field effect transistor, the fin field effect transistor comprising a substrate and a number of parallel spaced intervals on the substrate a semiconductor fin (Fin), each of the semiconductor fins including a top surface, a first sidewall and a second sidewall, wherein the doping method of the fin field effect transistor comprises the following steps: (a) Forming a doped layer on each of the top surface, the first sidewall, and the second sidewall of the semiconductor fin; and (b) implanting a sputter material along the normal direction of the substrate to each of the semiconductors A doped layer on the top surface of the fin to reduce the concentration of dopant elements therein.

Due to the vertical structure of Fin, the doping amount of the top surface is greater than the doping amount of the sidewall, which causes severe unevenness in top and sidewall doping. To this end, after the doping layer is completed, a process of implanting the sputter material is added to reduce the concentration of doping elements in the top surface, thereby ensuring uniformity of top and sidewall doping.

Preferably, the depth of implantation of the sputter material in step (a) is adjustable.

Preferably, the implantation depth of the sputter material in step (a) is consistent with the depth of the doped layer of the top surface of each of the semiconductor fins.

Preferably, step (a) further comprises the steps of: (a-1) implanting a doping element into a top surface and a first sidewall of each of the semiconductor fins; and (a-2) implanting the doping element into a top surface of each of the semiconductor fins And a second side wall.

In the doping method, after the implantation doping of the first sidewall and the second sidewall is completed, since the top surface is subjected to two ion implantations, the doping amount in the top surface is inevitably larger than the doping amount of the sidewall. In order to reduce this non-uniformity, a process of vertical implantation is added after doping the two sidewalls of the Fin, and a sputter material is implanted into the top doped layer, since the implantation direction is along the normal direction of the substrate. Therefore, the implantation of the sputter material does not affect the doping on the two sidewalls of Fin, but only affects the doping of the top. And after injecting the sputter material, the sputter material sputters a portion of the doping element in the top doped layer, thereby reducing the dose of the doping element in the top doped layer, thereby reducing the dose. The doping concentration helps to achieve uniformity of the top and sidewalls of the Fin.

Preferably, the step (a-1) further comprises self-saturating the dose of the doping element in the top surface of each of the semiconductor fins and the doped layer of the first sidewall, in step (a-2) The method further includes self-saturating the dose of the doping element in the doped layer of the top surface and the second sidewall of each of the semiconductor fins.

That is, the doping process of the two sidewalls for each Fin is such that first, a doping element is implanted into the first sidewall and implanted into the top surface until doping elements in the first sidewall The dose reaches self-saturation, wherein: a portion of the doping element is implanted into the first sidewall to form a doped layer; a portion of the doping element strikes the doped layer, and then the doping element in the doped layer is sputtered and sputtered out a doping element is incident on the second sidewall of the adjacent Fin to form a deposited layer on the second sidewall of the adjacent Fin, and then implanting a doping element into the second sidewall and implanting into the top surface until the first The dose of the doping element in the two sidewalls is saturated, wherein: a portion of the doping element is implanted into the second sidewall to form a doped layer; a portion of the doping element strikes the doped layer to sputter the doping element in the doped layer and the sputtered doping element is directed to the first sidewall of the adjacent Fin; a portion of the doping element strikes the deposited layer and sputters the The doping elements in the deposited layer and the sputtered doping elements are directed toward the first sidewall of the adjacent Fin.

Preferably, the step (a) further comprises repeatedly performing the steps (a-1) and (a-2) until the doping element in the doped layer of the first sidewall and the second sidewall of each of the semiconductor fins The dose reaches self-saturation.

Preferably, the implantation direction of the doping element is between 2° and 45° from the normal of the substrate, and the implantation energy of the doping element ranges from 200 eV to 2 keV, and the doping element is arsenic, phosphorus or Boron, the sputter material is at least one of a base element, an inert element, and a group IV element.

Preferably, the base element is ruthenium or osmium, and the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium.

Another preferred embodiment of the present invention adopts the following technical solution: a doping method of a fin field effect transistor, the fin field effect transistor comprising a substrate and a plurality of semiconductor fins disposed on the substrate and arranged in parallel Fin, each of the semiconductor fins includes a top surface, a first sidewall, and a second sidewall, wherein the doping method of the fin field effect transistor comprises the following steps: (i) in each of the Forming a doped layer on each of the top surface, the first sidewall, and the second sidewall of the semiconductor fin; and (ii) implanting a sputter material in a direction substantially flat to the top surface of each of the semiconductor fins And corresponding to the doping layers to reduce the concentration of the doping element therein, wherein an angle of the sputtering material injecting direction with the top surface of each of the semiconductor fins is greater than 0 degrees and less than or equal to 5 degrees.

In this technical solution, in order to solve the problem of uneven topping and sidewall doping of Fin, similarly, after the doping of Fin is completed, a process of implanting a sputter material is added, and an implantation direction almost parallel to the top surface is adopted. The sputtering material is implanted into the doped layer of the top surface, and the doping element in the doping layer 302 of the top surface of the Fin can be sputtered off after the sputtering material is implanted, thereby improving the doping uniformity of the top surface and the sidewall. .

Preferably, the step (i) further comprises the steps of: (i-1) implanting a doping element into the top surface and the first sidewall of each of the semiconductor fins; and (i-2) doping the doping An element is implanted into the top surface and the second sidewall of each of the semiconductor fins.

Preferably, the step (i-1) further comprises self-saturating the dose of the doping element in the top surface of each of the semiconductor fins and the doped layer of the first sidewall, in step (i-2) The method further includes self-saturating the dose of the doping element in the doped layer of the top surface and the second sidewall of each of the semiconductor fins.

Preferably, the step (a) further comprises repeatedly performing the steps (i-1) and (i-2) until the doping element in the doped layer of the first sidewall and the second sidewall of each of the semiconductor fins The dose reaches self-saturation.

The doping of the two sidewalls is specifically as follows. When the implantation of the first sidewall is performed: a part of the doping element is implanted into the first sidewall to form a doped layer; a part of the doping element strikes the doped layer and sputters the doping a doping element in the impurity layer and the sputtered doping element is directed to the second sidewall of the adjacent Fin to form a deposited layer on the second sidewall of the adjacent Fin, and when the second sidewall is implanted: the partially doped element is Injecting into the second sidewall to form a doped layer; a partially doped element impinges on the doped layer to sputter a doping element in the doped layer and the sputtered doping element is directed to the first sidewall of the adjacent Fin A portion of the doping element strikes the deposited layer to sputter the doping element in the deposited layer and the sputtered doping element is directed toward the first sidewall of the adjacent Fin.

Preferably, the implantation direction of the doping element is between 2° and 45° from the normal of the substrate, and the implantation energy of the doping element ranges from 200 eV to 2 keV, and the doping element is arsenic, phosphorus or Boron, the sputter material is at least one of a base element, an inert element, and a group IV element.

Preferably, the base element is ruthenium or osmium, and the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium.

The positive progress of the present invention is as follows: 1. The doping amount or concentration of the top is reduced by increasing the vertical injection of the sputter material after doping the sidewall of the Fin, or by substantially injecting the sputter material. Doping dose or concentration of small top to achieve uniform doping of the top and sidewalls of Fin.

2. When the doping of the sidewall of Fin is doped, the doping amount of the sidewall is self-saturated to ensure uniform doping at each position of each sidewall, and the doping of the two sidewalls of each Fin is also ensured. average.

3. Since the implantation energy of the doping element is controlled below 2 keV, that is, low energy implantation, the implantation depth of the doping element is shallow, and the damage to Fin is also small, which is favorable for the maintenance of the single crystal structure and improves the circle. The phenomenon of the angle reduces the wear on the Fin.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

(previous technology)

100, 200‧‧ units

124, 224‧‧‧Fins

20‧‧‧Base

22‧‧‧Shallow channel insulation area

(this invention)

100‧‧‧Base

200‧‧‧Semiconductor fins

301, 302‧‧‧Doped layer

Figure 1 is a schematic diagram of Fin in the prior art.

Figure 2 is a schematic view of the injection of a side wall of Fin.

Figure 3 is a schematic view of the injection of the other side wall of Fin.

Fig. 4 is a schematic view showing the wear of the two end angles of Fin in the prior art.

5 to 7 are schematic views of implantation according to Embodiment 2 of the present invention.

Figure 8 is a schematic view showing the injection of Embodiment 4 of the present invention.

The invention will be further described in the following by way of several examples, but not by way of This is to limit the invention to the scope of the described embodiments.

[Example 1]

In the doping method of the FinFET of the present embodiment, the Fin field effect transistor includes a substrate and a plurality of semiconductor fins (Fin) disposed in parallel on the substrate, each of The semiconductor fin includes a top surface, a first sidewall and a second sidewall. The doping method comprises the following steps:

(a) forming a doped layer on each of the top surface, the first sidewall and the second sidewall of each of the semiconductor fins; the doped layer can be completed by conventional techniques in the art, based on the vertical structure of Fin, The doping concentration of the top doped layer is necessarily greater than the doping concentration of the doped layer of the sidewall.

(b) implanting a sputter material along the normal direction of the substrate to the doped layer on the top surface of each of the semiconductor fins to reduce the concentration of the doping element therein; in this embodiment, sputtering The implantation depth of the material is adjustable, so that the distribution of the implantation depth of the sputter material in the top surface can be controlled, thereby increasing the effectiveness of sputtering; and ideally, the implantation depth of the sputter material can be combined with the doping layer. The depth is consistent, which can effectively reduce the concentration of doping elements in the top surface. The sputter material is at least one of a base element, an inert element, and a group IV element; the base element is ruthenium or osmium, and the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium. .

[Example 2]

Please refer to FIG. 5 to FIG. 7 , wherein the reference numeral 100 represents a substrate, and the reference numeral 200 represents Fin. The structure of the FinFET of the embodiment is the same as that of the embodiment 1. The doping method of the embodiment includes the following steps: As shown, a doping element is implanted into the top surface and the first sidewall of each of the semiconductor fins 200 until the top surface of each of the semiconductor fins 200 and the doped layers 301, 302 of the first sidewalls The dose of the doping element is self-saturated, wherein reference numeral 301 denotes a doped layer of the first sidewall, and reference numeral 302 denotes a doped layer representing the top surface. The self-saturation referred to here is the implanted doping element and the sputtered doping The equal dynamic state of the elements.

As shown in FIG. 6, the doping element is implanted into the top surface and the second sidewall of each of the semiconductor fins 200 up to the top surface of each of the semiconductor fins 200 and the doped layer 301 of the second sidewall. The dose of the doping element in 302 is self-saturated, wherein reference numeral 301 also denotes a doped layer of the second sidewall, and reference numeral 302 denotes a doped layer representing the top surface. It is worth noting that in order to form doping on the first and second sidewalls, the implantation direction of the doping element must be at an angle to the normal of the substrate, so that the top surface is implanted twice, resulting in The doping elements on the top surface are more than the doping elements on the sidewalls. In this embodiment, the implantation energy of the doping element is 1 keV.

As shown in FIG. 7, after the implantation of the doping element is completed, the sputter material is implanted into the doped layer 302 of the top surface of the Fin along the normal direction of the substrate 100 to reduce the concentration of the doping element therein; That is to say, after the sputtering material is implanted, a part of the doping element in the doping layer 302 of the top surface of Fin can be sputtered off, thereby reducing the doping concentration. The sputter material is at least one of a base element, an inert element, and a group IV element; the base element is ruthenium or osmium, and the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium. .

[Example 3]

Referring to FIG. 5 to FIG. 7 , the basic principle of Embodiment 3 is the same as that of Embodiment 2, except that in this embodiment, instead of using two injection methods, multiple injection methods are used, that is, multiple Ion implantation of the first sidewall and the second sidewall is performed in sequence until the dose of the doping element in the doped layer 301 of the two sidewalls is self-saturated, followed by vertical sputtering material implantation. The sputter material is at least one of a base element, an inert element, and a group IV element; the base element is ruthenium or osmium, and the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium. .

Reference is made to Example 2 where the rest are not mentioned.

[Example 4]

Referring to FIG. 5, FIG. 6, and FIG. 8, the basic principle of Embodiment 4 is the same as that of Embodiment 2, and the implantation of the erbium element is increased after the implantation of the doping element is completed, except for the injection direction.

First, as shown in FIGS. 5 and 6, a doping element is implanted to form doped layers 301, 302 on the top and side walls, and then, as shown in FIG. 8, the sputter material is in a direction substantially parallel to the top surface of Fin. The doping layer 302 is implanted to reduce the dose of the doping element therein. In this embodiment, the implantation direction of the sputter material is at an angle of 2° to the top surface of each of the semiconductor fins, and the doping element in the doped layer 302 of the top surface of the Fin may be implanted after the sputter material is implanted. Part of the sputtering is sputtered to increase the doping uniformity of the top and side walls.

[Effects Example 1]

First, the implantation of As is performed, the injection direction is 10° from the normal direction of the substrate, the implantation energy is 250 eV, and the initial implantation dose is 7.5e16 cm ^-2 , but is doped to the first sidewall and the second sidewall from saturation. The doping dose was 2.58e15 cm ^-2 and the doping dose at the top was 2.13e16 cm ^-2 .

Next, a base element (矽) of 5e15 cm ^-2 is vertically injected at an energy of 1 keV to the top surface (because it is vertical injection, so the sidewall is not affected), and the dose of As in the top surface is reduced to 1.54 due to sputtering. E16cm ^-2 .

It can be seen that dividing the dose of the top and side walls results in a uniformity ratio of the top and side walls of about 5:1, which is a significant improvement over the prior art 10:1.

[Effects Example 2]

First, the implantation of As is performed, the injection direction is at an angle of 20° with the normal direction of the substrate, the implantation energy is 250 eV, the initial implantation dose is 7.5 e16 cm ⁻² , and the self-saturation is doped into the first sidewall and the second sidewall. The doping dose was 3.33e15 cm ^-2 and the doping amount in the top surface was 1.83e16 cm ^-2 .

Next, a base element (矽) of 5e15 cm ^-2 is vertically injected at an energy of 1 keV to the top surface (because it is vertical injection, so the sidewall is not affected), and the dose of As in the top surface is reduced to 1.22e16 cm due to sputtering. ^-2 .

It can be seen that dividing the doses of the top and side walls results in a uniformity ratio of the top and side walls of about 3.7:1, which is a significant improvement over the prior art 10:1.

[Effects Embodiment 3]

First, the implantation of As is performed in the same manner as in the second embodiment, and the germanium element is vertically implanted into the top surface of the Fin along the normal direction of the substrate. The difference from the effect example 2 is that the amount of the germanium element implanted is 1.25. e16cm ^-2, under the influence of sputtering, the final dose of doping: the top surface: 6.7642e15cm ^-2, side walls: 3.3339e15cm ^-2. Thus the doping dose ratio of the top and side walls is about 2:1.

[Effects Example 4]

The doping of Fin is still referred to effect example 2, that is, the injection of As element is used until self-saturation, and then different from the above three effect embodiments, the injection of germanium element is not along the normal direction, but is almost along Parallel to the plane of the substrate, in the embodiment of the effect, the angle between the injection direction of the lanthanum element and the plane of the substrate is 2°, the energy is 1 keV, and the amount of lanthanum element is 8e16 cm ^-2 , at such an angle of almost parallel substrate, 矽The element will hit the top surface of Fin, some of the element will enter the top surface of Fin, and some of the element will cause As in Fin to be sputtered, thereby reducing the doping concentration of As in the top surface, and finally the top and side walls. The medium doping dose is: top surface: 1.2786e16cm ^-2 , side wall 3.3289e15cm ^-2 . The ratio of top surface to side wall is 3.84:1.

[Effects Example 5]

First, the implantation of As is performed. The injection direction is 10° to the normal direction of the substrate, the implantation energy is 200 eV, and the initial implantation dose is 7.5e15 cm ^-2 (two injections per minute, each injection of 3.25e15 cm ^-2 ) However, the doping amount doped into the first side wall and the second side wall from saturation is 9.9e14 cm ^-2 , and the doping amount at the top is 5.4e15 cm-2. It can be seen that the top doping at this time is much larger than the doping of the two sidewalls.

Next, an inert element (Ar) of 8e15 cm ^-2 is vertically injected at an energy of 3 keV to the top surface (since it is vertical injection, so the sidewall is not affected), and the dose of As in the top surface is reduced to 1.1e15 cm due to sputtering. ^-2 .

It can be seen that the ratio of the top surface to the side wall is divided to obtain a uniformity ratio of the top surface and the side wall of about 1.11:1, which is a significant improvement over the prior art 10:1.

Since the doping element has a lower energy at the time of implantation, in the present effect embodiment, it is 200 eV, and thus the amorphization condition is also improved. In the present effect embodiment, the thickness of the amorphized structure (on the side wall) is only 3 nm.

[Effects Example 6]

First, the implantation of As is carried out. The injection direction is 20° to the normal direction of the substrate, the implantation energy is 200 eV, and the initial implantation dose is 7.5e15 cm ^-2 (two injections per minute, each injection of 3.25e15 cm ^-2 ) The doping amount doped into the first sidewall and the second sidewall from saturation is 1.02e15 cm ^-2 , and the doping amount in the top surface is 5.3e15 cm ^-2 .

Next, an inert element (Ar) of 8e15 cm ^-2 is vertically injected at an energy of 3 keV to the top surface (since it is vertical injection, so the sidewall is not affected), and the dose of As in the top surface is reduced to 1.1e15 cm due to sputtering. ^-2 .

It can be seen that dividing the doses of the top and side walls results in a uniformity ratio of the top and side walls of about 1.1:1, which is a significant improvement over the prior art 10:1.

[Effects Example 7]

The doping of Fin is still referred to the effect of Embodiment 6, that is, the injection of As element is performed until self-saturation, and then unlike the above two effect embodiments, the injection of Ar element is not along the normal direction, but is almost along Parallel to the plane of the substrate, in the embodiment of the present embodiment, the angle of the injection of the Ar element is 2° with the plane of the substrate, the energy is 3 keV, and the amount of the Ar element is 2.3e17 cm ^-2 , at such an angle of almost parallel substrate, The Ar element will hit the top surface of Fin. A part of Ar will cause As in Fin to be sputtered, thereby reducing the doping amount or concentration of As in the top surface. The doping amount in the top surface and sidewall is: top surface. : 1.58e15cm ^-2 , side wall 1.02e15cm ^-2 . The ratio of top surface to side wall is 1.55:1.

[Effects Example 8]

Select 矽 as the substrate, firstly implant As, the injection direction is 10° from the normal direction of the substrate, the implantation energy is 200eV, and the initial implantation dose is 7.5e15cm ^-2 (two injections per minute, each injection) 3.25e15cm ^-2 ), but the doping amount doping into the first sidewall and the second sidewall from saturation is 9.9e14cm ^-2 , and the doping amount at the top is 5.4e15cm ^-2 . It can be seen that the top doping at this time is much larger than the doping of the two sidewalls.

Next, a 1.2e16cm ^-2 group IV element (Ge) is vertically implanted at a potential of ¹ keV to the top surface (due to the vertical implantation, so that the sidewall is not affected), and the dose of As in the top surface is reduced by sputtering. 1.3e15cm ^-2 .

It can be seen that the ratio of the top surface to the side wall is divided to obtain a uniformity ratio of the top surface and the side wall of about 1.31:1, which is a significant improvement over the prior art 10:1.

Since the doping element has a lower energy at the time of implantation, in the present effect embodiment, it is 200 eV, and thus the amorphization condition is also improved. In the present effect embodiment, the thickness of the amorphized structure (on the side wall) is only 3 nm.

[Effects Example 9]

The crucible is still used as the substrate. First, the implantation of As is performed. The angle between the injection direction and the normal direction of the substrate is 20°, the implantation energy is 200 eV, and the initial implantation dose is 7.5e15 cm ^-2 (two injections per minute). The implantation dose was 3.25e15 cm ^-2 ), the doping amount doped into the first side wall and the second side wall from saturation was 5.3e15 cm ^-2 , and the doping amount in the top surface was 1.0e15 cm ^-2 .

Next, a 1.2e16cm ^-2 group IV element (Ge) is vertically implanted at a potential of ¹ keV to the top surface (due to the vertical implantation, so that the sidewall is not affected), and the dose of As in the top surface is reduced by sputtering. 1.2e15cm ^-2 .

It can be seen that dividing the doses of the top and side walls results in a uniformity ratio of top and side walls of about 1.2:1, which is a significant improvement over the prior art 10:1.

From the above nine effect embodiments, the uniformity of doping on the top and side walls is significantly improved over the prior art.

In the interest of clarity of the various aspects of the invention, the various parts of the figures are not drawn to scale. The effect data for all effect examples was obtained using MATLAB (a computational analog software) analogy.

While the invention has been described with respect to the preferred embodiments of the present invention, it is understood that the scope of the invention is defined by the appended claims. A person skilled in the art can make various changes or modifications to the embodiments without departing from the spirit and scope of the invention, and such changes and modifications fall within the scope of the invention.

100‧‧‧Fin field effect transistor

301, 302‧‧‧Doped layer

Claims (14)

A method for doping a fin field effect transistor, the fin field effect transistor comprising a substrate and a plurality of semiconductor fins (Fin) disposed on the substrate and spaced apart from each other, each semiconductor fin including a top surface a first side wall and a second side wall, wherein the doping method of the fin field effect transistor comprises the steps of: (a) top surface, first side wall and second side of each of the semiconductor fins Forming a doped layer on each of the sidewalls; and (b) implanting a sputter material along a normal direction of the substrate to a doped layer on a top surface of each of the semiconductor fins to reduce doping elements therein concentration. The doping method of the fin field effect transistor according to claim 1, wherein the implantation depth of the sputtering material in the step (a) is adjustable. The method of doping a fin field effect transistor according to claim 2, wherein a depth of implantation of the sputter material is consistent with a depth of a doped layer of a top surface of each of the semiconductor fins. The method of doping a fin field effect transistor according to claim 1, wherein the step (a) further comprises the step of: (a-1) implanting a doping element into a top surface of each of the semiconductor fins and a first sidewall; and (a-2) implanting the doping element into a top surface and a second sidewall of each of the semiconductor fins. The doping method of the fin field effect transistor according to claim 4, wherein the step (a-1) further comprises doping the top surface of each of the semiconductor fins and the doping layer of the first sidewall The dose of the element is self-saturated, and step (a-2) further includes self-saturating the dose of the doping element in the doped layer of each of the top surface of the semiconductor fin and the second sidewall. The doping method of the fin field effect transistor according to claim 4, wherein the step (a) further comprises repeatedly performing the steps (a-1) and (a-2) until each of the semiconductor fins The dose of the doping element in the doped layer of the first sidewall and the second sidewall reaches self-saturation. The doping method of the fin field effect transistor according to any one of claims 4-6, wherein an angle of incidence of the doping element with an angle of a normal of the substrate is between 2° and 45°, the doping The implantation energy of the element ranges from 200 eV to 2 keV, and the doping element is arsenic, phosphorus or boron, and the sputtering material is at least one of a base element, an inert element and a group IV element. The doping method of the fin field effect transistor according to claim 7, wherein the base element is ruthenium or osmium, the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium. A method for doping a fin field effect transistor, the fin field effect transistor comprising a substrate and a plurality of semiconductor fins (Fin) disposed on the substrate and spaced apart from each other, each semiconductor fin including a top surface a first side wall and a second side wall, wherein the doping method of the fin field effect transistor comprises the steps of: (i) top surface, first side wall and second side of each of the semiconductor fins Forming a doped layer on each of the sidewalls; and (ii) implanting a sputter material into the corresponding doped layers in a direction substantially flat to the top surface of each of the semiconductor fins to reduce a concentration of the doping element, wherein an angle between an injection direction of the sputter material and a top surface of each of the semiconductor fins is greater than 0 degrees and less than or equal to 5 degrees. The method of doping a fin field effect transistor according to claim 9, wherein the step (i) further comprises the step of: (i-1) implanting a doping element into a top surface of each of the semiconductor fins and a first sidewall; and (i-2) implanting the doping element into a top surface and a second sidewall of each of the semiconductor fins. The doping method of the fin field effect transistor according to claim 10, wherein the step (i-1) The method further includes self-saturating the dose of the doping element in the top surface of each of the semiconductor fins and the doped layer of the first sidewall, and step (i-2) further including: each of the semiconductor fins The dose of the doping element in the top surface and the doped layer of the second sidewall is self-saturated. The doping method of the fin field effect transistor according to claim 10, wherein the step (a) further comprises repeatedly performing the steps (i-1) and (i-2) until the first of each of the semiconductor fins The dose of the doping element in the doped layer of the sidewall and the second sidewall is self-saturated. The method for doping a fin field effect transistor according to any one of claims 10 to 12, wherein an angle of incidence of the doping element with an angle of a normal of the substrate is between 2° and 45°, the doping The implantation energy of the element ranges from 200 eV to 2 keV, and the doping element is arsenic, phosphorus or boron, and the sputtering material is at least one of a base element, an inert element and a group 1V element. The doping method of the fin field effect transistor according to claim 13, wherein the substrate element is ruthenium or osmium, the inert element is ruthenium, argon, osmium or iridium, and the group IV element is carbon, ruthenium or osmium.