TWI406410B - Semiconducting nanostructure - Google Patents

Abstract

The present invention relates to a semiconducting nanostructure. The semiconducting nanostructure includes a substrate and at least one ridge. The substrate includes a first crystal plane and a second crystal plane perpendicular to the first crystal plane. The at least one ridge extends from the first crystal plane along a crystal orientation of the second crystal plane.

Description

Semiconductor nanostructure

The present invention relates to a semiconductor nanostructure, and more particularly to a two-dimensional semiconductor nanostructure.

As the process scale of semiconductor electronic devices enters the nanometer scale, the scale of the inner core cell transistor is also required to develop to the nanometer scale. Metal oxide semiconductor field effect transistors (MOSFETs), which are commonly used in semiconductor electronic devices, when the scale of the metal oxide semiconductor field effect transistor is reduced to the order of nanometers, the physical properties of the P-type or N-type semiconductor structure The performance has also changed, mainly due to the significant decrease in the mobility of carriers (electrons or holes) in the semiconductor structure. In the prior art, the semiconductor structure applied to the MOSFET is mostly a film-like structure. In order to increase the carrier migration rate, a method is generally employed to apply a stress to change the lattice size of the semiconductor structure, thereby making the semiconductor The energy band of the structure changes, and the change in the band increases the mobility of carriers in the semiconductor structure. However, the above method fails to consider another important factor "impurity scattering" that restricts the increase in carrier mobility in a semiconductor structure. The impurity scattering means that when a carrier passes through an impurity atom, a Coulomb force interaction exists between the carrier and the impurity atom, so that the impurity atom and the carrier mutually attract or repel each other, thereby making the Carrier migration The offset occurs.

See "Quantum confinement of crystalline silicon nanotubes with nonuniform wall thickness: Implication to modulation doping", Appl. Phys. Lett, B. Yan et al, Vol 91, P103107 (2007)", which finds that the doped one The U.S. tube has a phenomenon in which the impurity scattering is small. Specifically, the U-tube has a non-uniform wall thickness, and the unevenness of the wall thickness allows the carrier to be positioned in a thicker wall. In practical applications, in order to increase the carrier concentration, the literature discloses that P-type or N-type doping can be performed in a thinner wall, the doping element will remain in the thinner wall, and the carrier will be mostly Distributed in a thicker wall, the phenomenon that the doping element is separated from the carrier phase can reduce the scattering of impurities that affect carrier mobility.

However, the semiconductor nanostructure disclosed in this document is only a one-dimensional semiconductor nanostructure, and its structure for reducing the scattering of impurities cannot be applied to a two-dimensional semiconductor nanostructure, that is, it does not reveal a kind of impurity reduction. A two-dimensional semiconductor nanostructure that affects the mobility of carriers.

In view of this, it is necessary to provide a two-dimensional semiconductor nanostructure which can reduce the influence of impurity scattering on carrier mobility.

A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate The first crystal plane begins to extend along the crystal plane orientation of the second crystal plane.

A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate The first crystal plane begins to extend along the crystal plane orientation of the second crystal plane, and the material of the substrate is germanium, and the material of the spine is composed of germanium and a plurality of P-type dopant atoms uniformly dispersed in the crucible. The crystal plane orientation of the first crystal plane is (110), and the crystal plane orientation of the second crystal plane is (001) perpendicular to the orientation of the first crystal plane, and the width of the cross section at one half height of the ridge is less than 10 nm. Meter.

A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate The first crystal plane begins to extend along the crystal plane orientation of the second crystal plane, and the material of the substrate is germanium, and the material of the spine is composed of germanium and a plurality of N-type dopant atoms uniformly dispersed in the crucible. The crystal plane orientation of the first crystal plane is (001), and the crystal plane orientation of the second crystal plane is perpendicular to the (110) orientation of the first crystal plane, and the width of the cross section at one half height of the ridge is less than 10 Nano.

Compared with the prior art, since the semiconductor nanostructure provided by the present invention allows holes or electrons to be strongly bound in the substrate, and according to the modulation doping effect, the doping atoms and holes of the ridge are spatially separated from each other. That is, most of the doping atoms are distributed in the ridge, and holes or electrons are mostly distributed in the substrate, so that the scattering of impurities has less influence on the migration speed of holes or electrons, thereby greatly increasing the holes or electrons. Migration speed.

10,20‧‧‧Semiconductor nanostructure

12,22‧‧‧Base

13,23‧‧‧First crystal face

14,24‧‧‧ ridge

15,25‧‧‧second crystal face

16,26‧‧‧Channel

18,28‧‧‧protection layer

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a semiconductor nanostructure according to a first embodiment of the present invention.

Fig. 2 is a view showing the relationship between the occupation ratio of holes in the ridges, the energy difference between the ridges and the substrate, and the width of the top surface of the ridges in the semiconductor nanostructure of the first embodiment of the present invention.

3 is a schematic view showing the structure of a semiconductor nanostructure according to a second embodiment of the present invention.

The semiconductor nanostructure provided by the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

The present invention provides a semiconductor nanostructure comprising a substrate and at least one ridge. The substrate includes a first crystal plane and a second crystal plane perpendicular to the first crystal plane, and the at least one ridge is oriented from the first crystal plane of the substrate along the crystal plane of the second crystal plane Extend out. The crystal plane orientation of the first crystal plane is (001) or (110), and the crystal plane orientation of the second crystal plane is (110) or (001) perpendicular to the crystal plane orientation of the first crystal plane. Specifically, if the crystal plane orientation of the first crystal plane of the substrate is (001), the crystal plane orientation (110) of the second crystal plane of the substrate, if the crystal plane orientation of the first crystal plane of the substrate is ( 110), the crystal plane orientation of the second crystal face of the substrate is (001).

Referring to FIG. 1, a first embodiment of the present invention provides a semiconductor nanostructure 10 including a substrate 12, a plurality of ridges 14, and a plurality of channels 16. The substrate 12 has a first crystal plane 13 having a crystal plane orientation of (110) and a second crystal plane 15 having a crystal plane orientation of (001). The plurality of ridges 14 are oriented from the first crystal plane 13 in the substrate 12 along the crystal plane of the second crystal plane 15 ( 001) is extended, and the plurality of ridges 14 are continuously spaced apart along the length direction of the substrate 12. The adjacent two ridges 14 are defined as a channel 16.

The substrate 12 is a semiconductor material formed by laminating a plurality of atomic layers of the semiconductor material, and the material thereof may specifically be tantalum, niobium, tantalum carbide or tantalum or the like. The shape of the substrate 12 is a film-like structure in which the thickness direction is the z-axis direction, the width direction is the x-axis direction, and the length direction is the y-axis direction. The width and length of the substrate 12 are not limited and can be selected according to actual needs. The thickness of the substrate 12 cannot be too large, and if it is too large, the quantum confinement effect does not occur, so that holes cannot be confined to the inside of the substrate 12. Therefore, the substrate 12 should have a small thickness when the thickness of the substrate 12 is When the value is as small as a fixed value, the energy level is changed, so that the quantum confinement effect occurs. Preferably, the thickness of the substrate 12 is 5 atomic layers of the base material layer to 15 atomic layers of the base material. In this embodiment, the substrate 12 is a single crystal germanium film having a thickness of 8 germanium atoms, that is, the thickness of the germanium film is 13.4 Å. The so-called quantum confinement effect means that at least one dimension in the microstructure is equivalent to the deBroglie wavelength, so the motion of electrons in this dimension is limited, the electronic state is quantized, and the continuous energy band is decomposed into Discrete energy levels, when the energy level spacing is greater than some characteristic energy (such as thermal motion), the microstructure will exhibit even unique properties that are different from bulk samples.

The ridge 14 is integrally formed with the substrate 12, and the material of the ridge 14 is the same as that of the substrate 12. This embodiment is a single crystal crucible. The host material of the ridge portion 14 is further uniformly doped with an acceptor dopant atom, and the concentration of the acceptor dopant atom in the substrate 12 is not limited, and may be selected according to actual conditions. The subject The main doping atom may be boron, indium or gallium, etc., and the acceptor doping atom may cause the entire semiconductor nanostructure 10 to have a higher concentration of holes, thereby making the entire semiconductor nanostructure 10 a P-type semiconductor Rice structure.

In this embodiment, the plurality of ridges 14 are uniformly doped with boron as the acceptor atom. The doping atoms are only doped to the ridges 14. According to the modulation doping effect, the doping atoms and the holes are spatially separated, that is, after doping, the doping atoms are substantially distributed in the plurality of ridges. In 14, the holes provided by the dopant atoms are mostly distributed in the substrate 12.

The ridge portion 14 may have any shape with a height direction of a z-axis direction and a height greater than that of the atomic layers of the four base materials. The higher the height, the higher the content of dopant atoms doped into the ridge portion 14 may be. And the content of holes provided by the dopant atoms is also higher. According to the quantum confinement effect, most of the holes provided by the dopant atoms are confined in the substrate 12, so that the substrate 12 of the semiconductor nanostructure 10 can be made. Has a larger hole concentration. The width direction of the ridge portion 14 is the y-axis direction, and the width and length of the ridge portion 14 are set based on the cross-sectional width and length at one half height of the ridge portion 14. The half-height of the ridge portion 14 has a smaller cross-sectional width. 10 nm. In addition, the width of the plurality of ridges 14 may be the same or different. The longitudinal direction of the section at the half height of the ridge 14 is the x-axis direction in the drawing, and the length is not limited.

In this embodiment, the ridge portion 14 has a cubic shape, and the height of the ridge portion 14 is the height of the atomic layer of the four base materials, that is, 5.5 Å. The length of the ridge 14 may be the same as or different from the width of the substrate 12. In this embodiment, the length of the ridge 14 is the same as the width of the substrate 12.

Referring to FIG. 2, the dotted line indicates the relationship between the width of the ridge 14 and the energy between the ridge 14 and the substrate 12. As can be seen from the figure, the energy difference between the substrate 12 and the ridge 14 and the ridge 14 The width is inversely proportional. Therefore, when the width of the ridge 14 is small, as shown in the figure, less than 10 nm, the energy difference between the ridge 14 and the substrate 12 is large, and the quantum confinement effect is more obvious, so that the hole is It is strongly confined to the substrate 12, so that the mobility of holes can be improved. The solid line in the figure indicates the relationship between the width of the ridge 14 and the occupancy of the cavity at the ridge 14. As can be seen from the figure, the occupancy of the cavity in the ridge 14 is proportional to the width of the ridge 14, that is, As the width of the top surface of the ridge 14 becomes larger, the occupancy of the cavity in the ridge 14 becomes larger. It can be seen from the figure that the cavity occupancy of the ridge 14 is less than 10 nm. Smaller, i.e., less than 14%, has a significant quantum confinement effect such that only a small portion of the holes provided by the dopant atoms are distributed in the ridges 14, most of which are distributed in the substrate 12, since the ridges 14 have A larger number of doped atoms make the scattering of impurities affecting the hole mobility in the substrate 12 less pronounced, resulting in higher hole mobility. Therefore, the smaller the width of the ridge 14 is, the more pronounced the quantum confinement effect is, the larger the hole occupation ratio in the substrate 12 of the semiconductor nanostructure 10 is, and since the ridge 14 has more dopant atoms, The scattering of impurities is made inconspicuous, and the hole mobility becomes high. The width of the ridge 14 should be less than 10 nm, preferably 0.6 nm to 2.1 nm. In this embodiment, the width of the ridge 14 is 1 nm.

The width of the channel 16, i.e., the distance between adjacent two ridges 14 is such that there is no direct interaction between the adjacent two ridges 14 so that the ridge 14 is empty. The holes can only move to the substrate 12, but cannot move between the respective ridges 14, making the quantum confinement effect more pronounced, and the width of the channel 16 The direction is the y-axis direction in the figure. In this embodiment, the width of the channel 16 needs to be greater than 10 atomic layers of the base material.

It can be seen that the semiconductor nanostructure 10 as a whole is a patterned structure which can cause a quantum confinement effect, the distribution of holes is significantly modulated, and the holes are strongly bound in the substrate 12. The ridge portion 14 extends from the first crystal face 13 of the substrate 12 along the crystal face orientation (001) of the second crystal face 15, and the extension direction causes the energy bands in the substrate 12 and the ridge portion 14 to be respectively The anisotropy, so that the valence band top in the semiconductor nanostructure 10 is strongly confined within the substrate 12, so that the distribution of the holes of the entire semiconductor nanostructure 10 is modulated such that the holes are strongly confined to the substrate 12. Inside. Specifically, the patterned semiconductor nanostructure 10 can have a banding effect on the energy band therein and form a first sub-valency band and a second sub-valence band, and the valence band of the band is away from the second sub-portion. The valence band, that is, the wider band gap between the top of the valence band and the second sub-price band, makes the hole more difficult to transition between the two, so the migration of holes is mainly the first around the top of the valence band. The influence of the sub-valence band, and the valence band top has substantially the same spatial distribution as the holes in the first sub-valence band, that is, the holes therein are substantially completely distributed inside the substrate 12, so that the quantum confinement effect is obvious, that is, Most of the holes of the semiconductor nanostructure 10 are confined in the substrate 12.

In addition, the semiconductor nanostructure 10 further includes a protective layer 18 covering all surfaces of the semiconductor nanostructure 10, or only the ridges 14 and trenches of the semiconductor nanostructure 10 The surface of the track 16 prevents lattice relaxation on the surface of the semiconductor nanostructure 10, affecting the physical properties of the entire structure. In this embodiment, the protective layer 18 is a hydrogen atom layer.

It can be understood that the ridge portion 14 of the semiconductor nanostructure 10 can also be one. The specific number can be determined according to the concentration of carriers required in practical applications. If a higher carrier concentration is required, more can be set. The ridges 14 are thus doped with more acceptor atoms. If the required carrier concentration is lower, fewer ridges 14 can be provided, so that fewer acceptor atoms can be doped.

Referring to FIG. 3, a second embodiment of the present invention provides a semiconductor nanostructure 20 including a substrate 22, a plurality of ridges 24, and a plurality of channels 26. The substrate 22 includes a first crystal plane 23 having a crystal plane orientation of (001) and a second crystal plane 25 having a crystal plane orientation of (110); the plurality of ridge portions 24 from the first crystal plane of the substrate 22 23 begins to extend along the crystal plane orientation (110) of the second crystal plane 25, and the plurality of ridges 24 are spaced apart from each other; the adjacent two ridges 24 are defined as a channel 26.

The surface of the semiconductor nanostructure 20 further includes a protective layer 28 overlying the surface of the plurality of ridges 24 and the plurality of trenches 26 of the semiconductor nanostructure 20. The difference between this embodiment and the first embodiment is that the crystal plane orientation of the first crystal plane 23 in the present embodiment is (001), and the crystal plane orientation of the second crystal plane 25 is (110).

The material of the ridge portion 24 is the same as the material of the substrate 22, and the material of the ridge portion 24 further includes a donor dopant atom uniformly doped to the host material, and the donor dopant atom may be phosphorus, arsenic or antimony. Alternatively, the donor dopant atoms can cause the entire semiconductor nanostructure 20 to have a higher concentration of electrons, thereby making the entire semiconductor nanostructure 20 an N-type semiconductor nanostructure.

In this embodiment, the dimensions of the substrate 22, the ridges 24, and the channels 26 of the semiconductor nanostructure 20, such as the length, width, and height, affect the properties of the semiconductor nanostructure 20, and are the same as in the first embodiment. The size of the substrate 12, the ridges 14 and the channels 16 have similar effects on the properties of the semiconductor nanostructures 10. Therefore, the substrate 22, the ridges 24 and the trenches 26 have a size selection principle and the substrate of the first embodiment. 12. The selection of the dimensions of the ridges 14 and the channels 16 is the same, and will not be described herein.

The semiconductor nanostructure 20 in this embodiment is a patterned structure that can make the energy band anisotropy in the substrate 22 and the ridges 24 such that the valence band top is strongly confined within the substrate 22. Thereby the electron distribution is significantly modulated. Specifically, the patterned semiconductor nanostructure 20 can have a banding effect on the energy band therein and form a first sub-valence band and a second sub-valency band, and the band edge of the band is away from the second sub-portion The valence band, that is, the wide band gap between the top of the price band and the second sub-price band makes the electrons difficult to transition between the two. Therefore, the migration of electrons is mainly subject to the first sub-price around the top of the price band. The influence of the band, and the valence band top has substantially the same spatial distribution as the electrons in the first sub-valence band, that is, the electrons therein are substantially completely distributed inside the substrate 22, so that the quantum confinement effect is obvious, and the electrons are strongly It is trapped in the substrate 22, and the electrons are spatially separated from the above-mentioned dopant atoms, thereby reducing the influence of impurity scattering on the electron mobility. It can be understood that the number of ridges can also be selected as one, and the specific number depends on the concentration of carriers required in practical applications.

The semiconductor nanostructure of the embodiment of the invention has the following advantages: the semiconductor nanostructure provided by the embodiment of the invention can make holes or electrons strongly bound In the substrate, and according to the modulation doping effect, the doping atoms and electrons or holes of the ridge are spatially separated from each other, that is, the doping atoms are mostly distributed in the ridge, and the holes or electrons are mostly distributed on the substrate. Therefore, the scattering of impurities has less influence on the mobility of holes or electrons, thereby greatly increasing the mobility of holes or electrons.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Semiconductor nanostructure

12‧‧‧Base

13‧‧‧First crystal face

14‧‧‧ ridge

15‧‧‧Second crystal face

16‧‧‧Channel

18‧‧‧Protective layer

Claims (17)

A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate The first crystal plane begins to extend along the crystal plane orientation of the second crystal plane, and the thickness of the substrate is a thickness of 5 atomic layers of the base material to 15 atomic layers of the base material. The semiconductor nanostructure of claim 1, wherein the crystal plane orientation of the first crystal plane is (110), and the crystal plane orientation of the second crystal plane is (001). The semiconductor nanostructure of claim 1, wherein the crystal plane orientation of the first crystal plane is (001), and the crystal plane orientation of the second crystal plane is (110). The semiconductor nanostructure of claim 2, wherein the cross-sectional width at one half of the ridge is less than 10 nm. The semiconductor nanostructure of claim 2, wherein the ridge is further doped with a dopant atom, and the dopant atom is boron, indium or gallium. The semiconductor nanostructure of claim 3, wherein the ridge is further doped with a dopant atom, which is phosphorus, arsenic or antimony. The semiconductor nanostructure of claim 2, wherein the semiconductor nanostructure comprises a plurality of ridges, the plurality of ridges being continuously spaced apart along a length of the substrate, the adjacent two The ridges are defined as a channel. The semiconductor nanostructure of claim 7, wherein the substrate is formed by laminating a plurality of atomic layers. The semiconductor nanostructure of claim 8, wherein the channel Width greater than 10 atomic layers of substrate material. The semiconductor nanostructure of claim 8, wherein the thickness of the substrate is 8 thicknesses of the atomic layer of the base material. The semiconductor nanostructure of claim 1, wherein the material of the substrate and the ridge is ruthenium. The semiconductor nanostructure of claim 1, wherein the semiconductor nanostructure further comprises a protective layer disposed on the ridge and the channel surface of the semiconductor nanostructure. The semiconductor nanostructure of claim 12, wherein the protective layer is composed of a plurality of hydrogen atoms. A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate The first crystal plane begins to extend along the crystal plane orientation of the second crystal plane, and the material of the substrate is germanium, and the material of the spine is composed of germanium and a plurality of P-type dopant atoms uniformly dispersed in the crucible. The crystal plane orientation of the first crystal plane is (110), and the crystal plane orientation of the second crystal plane is (001) perpendicular to the orientation of the first crystal plane, and the width of the cross section at one half height of the ridge is less than 10 nm. Meter. The semiconductor nanostructure of claim 14, wherein the semiconductor nanostructure comprises a plurality of ridges defined as a channel between the two adjacent ridges, the channel having a width greater than 10 An atomic layer of the substrate material. A semiconductor nanostructure comprising: a substrate and at least one ridge, the substrate comprising a first crystal plane and a second crystal plane perpendicular to the first crystal plane, the at least one ridge from the substrate a first crystal face begins along the second crystal face The orientation of the crystal plane is extended, and the material of the substrate is ruthenium, and the material of the ridge portion is composed of ruthenium and a plurality of N-type dopant atoms uniformly dispersed in the ruthenium, and the crystal plane orientation of the first crystal plane is (001), The crystal plane orientation of the second crystal plane is oriented perpendicular to the first crystal plane orientation (110), and the width of the cross section at one half height of the ridge portion is less than 10 nm. The semiconductor nanostructure of claim 16, wherein the semiconductor nanostructure comprises a plurality of ridges defined as a channel between the two adjacent ridges, the channel having a width greater than 10 An atomic layer of the substrate material.