A method for doping of a material, a method of fabricating an electronic device and an electronic device
Strain-assisted ion implantation improves diamond doping efficiency and accuracy by temporarily expanding its lattice, addressing the challenges of low efficiency and accuracy in existing methods, enabling efficient diamond semiconductor production.
Patent Information
- Application Number
- PCT/CN2025/078259
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-02-29
- Filing Date
- 2025-02-20
- Publication Date
- 2025-09-04
AI Technical Summary
Diamond's rigid lattice structure makes it difficult to introduce dopants efficiently, leading to low doping efficiency and accuracy in ion implantation and epitaxial growth, hindering the development of diamond semiconductor devices.
Applying strain-assisted ion implantation by temporarily increasing the lattice constant of diamond through tensile strain, followed by ion implantation and restoring the lattice to its original state, allowing precise and efficient doping.
Enhances doping efficiency and accuracy, enabling higher doping concentrations with reduced crystal damage, facilitating mass production of diamond semiconductor devices.
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Abstract
Description
A METHOD FOR DOPING OF A MATERIAL, A METHOD OF FABRICATING AN ELECTRONIC DEVICE AND AN ELECTRONIC DEVICETechnical Field:
[0001] The present invention relates to doping technique, in particularly to strain-assisted doping of diamond for improving doping efficiency thereof.Background:
[0002] It is essential to dope semiconductor materials and make them n-or p-type semiconductive in order to make any basic electronic devices. The doping process can be finished by diffusion, ion implantation or epitaxial growth. So far, the most widely employed doping method for semiconductor especially integrated circuit (IC) is ion implantation, which has been proved to be more precise, more reliable and more repeatable compared with diffusion and epitaxial growth.
[0003] In this regard, doping is an essential and one of the basic processes for making semiconductor devices. In the doping process, one or more elements are introduced into a material (e.g., the doping of phosphorus to make n-type or boron to making p-type in silicon) .
[0004] During ion implantation, the dopant element is accelerated into a specific region of the solid target (e.g., silicon) , changing its electrical properties. While silicon has been developed as the most popular semiconductor material, it has some limitations. For example, with the decrease of transistor size, more transistors are being integrated into a certain area (e.g., in CPU and GPU) . As a result, more heat is generated, and due to that silicon only has a thermal conductivity of 1.5 W cm-1 K-1, efficient heat dissipation becomes a challenge, which limits the performance of semiconductor devices.
[0005] Diamond, as an ultra-wide bandgap semiconductor material, has a high thermal conductivity of 24 W cm-1 K-1, which can overcome the heat dissipation problem. Moreover, diamond has a crystal structure of isometric form (similar with that of silicon, which does not suffer from piezoelectricity effect) , therefore can be applied in integrated circuits, making diamond a promising candidate for semiconductor industry. However, due to the very rigid lattice structure of diamond, it is difficult to be doped. That is, for diamond, due to its rigid lattice and small lattice parameter, it is hard to introduce other elements into diamond, which remains to be a problem not only for the doping of diamond, but also for the development of diamond semiconductor devices.
[0006] The ion-implantation method has been demonstrated to have a very low doping efficiency in diamond and it can easily bring damage to diamond lattice. So far, the doping of diamond is mainly completed during epitaxial growth of chemical vapor deposition. However, during the doping of epitaxial growth, the whole material is doped, which cannot achieve doping for a specific small region (which is essential for making integrated circuits) , and the slow growth speed cannot guarantee mass production.
[0007] Therefore, there is a need for improving the efficiency of the ion-implantation process and making it more suitable for the doping of diamond and for the mass production of diamond electronic devices.Summary of Invention:
[0008] It is an objective of the present invention to provide devices and methods to address the aforementioned shortcomings and unmet needs in the state of the art. To tackle such the problems, a strain-assisted doping strategy is proposed in the present invention. The lattice parameter of diamond is elastically stretched, followed by the doping of elements. In this manner, the doping efficiency can be improved. As such, the method of the present invention solves the problem of low doping efficiency of diamond.
[0009] The existing doping technique of diamond usually includes: (1) ion implantation doping or (2) epitaxial growth doping. For ion implantation doping, the dopant element is accelerated into a solid target. However, when the lattice parameter of the target (e.g., diamond) is too small, the ion implantation becomes difficult to take place. Therefore, epitaxial growth doping has been more commonly used. However, doping during epitaxial growth cannot realize precise doping of an accurate position.
[0010] In the present invention, the provided approach is the strain-assisted ion implantation doping, of which the lattice structure of the target is stretched, which allows a higher doping efficiency by ion implantation. Compared with the existing epitaxial growth doping and conventional ion implantation doping, the provided approach of the present invention can achieve the result of both high efficiency and high accuracy of both dose and the depth.
[0011] In accordance to a first aspect of the present invention, there is provided a method for doping of a material, comprising: providing a wafer of an intrinsic material; temporally increasing a crystal volume or a lattice constant of the wafer thereby increasing a doping efficiency in an ion implantation process; performing ion implantation to introduce dopant atoms into the wafer with the increased crystal volume or lattice constant; restoring the crystal volume or the lattice constant to an original value of the intrinsic material; and activating the dopant atoms within the wafer.
[0012] In accordance with the first aspect, the intrinsic material includes a semiconductor material.
[0013] In accordance with the first aspect, the wafer is provided on a substrate having a high modulus mechanical property.
[0014] In accordance with the first aspect, the step of temporally increasing the crystal volume or the lattice constant comprising the step of deforming the wafer by applying tensile strain with a predetermined strain value to the wafer.
[0015] In accordance with the first aspect, the tensile strain is applied to the wafer of the intrinsic material along the
[0111] crystalline orientation.
[0016] In accordance with the first aspect, the predetermined strain values of the tensile strain applied to a diamond wafer ranges from 0 to 9%.
[0017] In accordance with the first aspect, the dopant atoms comprise phosphorus for n-type dopants of the diamond wafer or boron for p-type dopants of the diamond wafer.
[0018] In accordance with the first aspect, the predetermined strain values of the tensile strain applied to a gallium nitride wafer ranges from 0 to 14%.
[0019] In accordance with the first aspect, the dopant atoms comprise germanium / silicon for n-type dopants of the gallium nitride wafer, or magnesium for p-type dopants of the gallium nitride wafer.
[0020] In accordance with the first aspect, the predetermined strain values of the tensile strain applied to a silicon wafer ranges from 0 to 16%.
[0021] In accordance with the first aspect, the dopant atoms comprise phosphorus / arsenic for n-type dopants of the silicon wafer, or boron for p-type dopants of the silicon wafer.
[0022] In accordance with the first aspect, the predetermined strain values of the tensile strain applied to a silicon carbide wafer ranges from 0 to 15%.
[0023] In accordance with the first aspect, the dopant atoms comprise phosphorus / nitrogen for n-type dopants of the silicon carbide wafer, or aluminium for p-type dopants of the silicon carbide wafer.
[0024] In accordance with the first aspect, the dopant atoms are activated by high-temperature annealing.
[0025] In accordance with the first aspect, the wafer of the intrinsic material is fixed on a substrate layer.
[0026] In accordance with the first aspect, the method further comprises the step of defining a doped region for ion implantation such that the dopant atoms are introduced to only within the doped region of the layer of intrinsic material.
[0027] In accordance with the first aspect, the step of providing a wafer of an intrinsic material comprises the step of depositing the layer of intrinsic material on the substrate layer using chemical vapor deposition.
[0028] In accordance with a second aspect of the present invention, there is provided a method of fabricating an electronic device, comprising the step of: preparing a wafer having a doped region of an intrinsic material doped with dopant atoms according the method of the first aspect, and fabricating the electronic device including two or more electrodes disposed on the layer of intrinsic material.
[0029] In accordance with the second aspect, the electronic device comprises a source electrode, a drain electrode and a gate electrode, wherein the gate electrode is disposed above the doped region and between the source electrode and the drain electrode.
[0030] In accordance with a third aspect of the present invention, there is provided an electronic device comprising a layer of intrinsic material processed by the method in accordance with the second aspect.
[0031] By using the strain-assisted doping strategy, the lattice structure of diamond is stretched elastically, making it easier to introduce the dopant into diamond, so as to improve / solve the afore-mentioned problems as follows.
[0032] (1) The main challenge of the ion implantation of diamond is the low doping efficiency caused by the rigid and small lattice structure of diamond. In the present invention, elastic strain engineering is employed to increase the lattice constant of diamond temporarily, which tackles the low doping efficiency problem, and allows a higher doping concentration with less crystal damage.
[0033] (2) By employing the strain-assisted doping, ion-implantation becomes possible for diamond, which can solve the low doping accuracy (of both dose and depth) problem of epitaxial growth.Brief Description of Drawings:
[0034] Embodiments of the invention are described in more details hereinafter with reference to the drawings, in which:
[0035] FIG. 1 shows schematic drawings of strain-assisted doping of phosphorus in diamond according to one embodiment of the present invention;
[0036] FIG. 2 shows formation energy change of phosphorus doping of diamond with tensile and compressive strain applied according to one embodiment of the present invention;
[0037] FIG. 3 shows schematic drawings of stain-assisted doping of diamond according to one embodiment of the present invention;
[0038] FIG. 4A shows a schematic drawing of ion-implantation according to one embodiment of the present invention;
[0039] FIG. 4B shows a process flow diagram of the method for doping of a material in accordance with an embodiment of the present invention;
[0040] FIG. 5 shows a flowchart of the process of strain-assisted doping according to one embodiment of the present invention; and
[0041] FIG. 6 is an illustration showing a step-by-step change of the material of the doped layer after each step of the doping process in accordance with an embodiment of the present invention.Detailed Description of the Invention:
[0042] In the following description, devices and methods using strain-assisted doping of diamond for improving doping efficiency thereof and the likes are set forth as preferred examples. It will be apparent to those skilled in the art that modifications, including additions and / or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.
[0043] It is to state that diamond itself is extremely difficult to be doped and so that how to dope diamond well serves as an inventive part of the present invention. The present invention aims to tackle the diamond doping challenge, while other existing prior arts are hardly made for dealing with this challenge. Herein, in the present disclosure, in various embodiments, there are diamond for an ultra-wide bandgap material, phosphorus for n-type dopant of diamond, and boron for p-type dopant of diamond.
[0044] Taking the doping of phosphorus in diamond as an example. Due to the relatively larger atom size of phosphorus compared with carbon, phosphorus has a low doping efficiency in diamond crystal. Thus, the most commonly used way to dope diamond with phosphorus is by introducing phosphorus during epitaxial growth of diamond, while the ion implantation method is hard to achieve.
[0045] With reference to Figures 1 to 6, there is shown an embodiment of strain-assist doping of an intrinsic material with dopant atoms. In this example, the doping method comprising the steps of: providing a wafer of an intrinsic material; temporally increasing a crystal volume or a lattice constant of the intrinsic material thereby increasing a doping efficiency in an ion implantation process; performing ion implantation on the wafer to introduce dopant atoms into the wafer with the increased crystal volume or lattice constant; restoring the crystal volume or the lattice constant to an original value of the intrinsic material; and activating the dopant atoms within the wafer.
[0046] In this example, dopant materials, such as boron and phosphorous, may be introduce to intrinsic semiconducting material such as silicon and diamond (i.e. cardon with the diamond lattice structure) by ion-implantation, where C / Si atoms in the lattice by the introduced a predetermined number of B / P atoms to provide a desired amount of electron or holes to increase electronic carrier concentration of the material when compare to that of the intrinsic material.
[0047] Without wishing to be bound by theory, the dopants needs to be activated upon forming strong chemical bonds with the atoms of the intrinsic material, thus it is preferable that the dopant atoms are successfully introduced physically into the material followed by an annealing process that facilitate chemical bond formation to rearrange the atoms of the dopants as well as the intrinsic / semiconductor material in a proper lattice configuration. Preferably, the method in accordance with the present invention includes specially a step of temporally increasing a crystal volume or a lattice constant of the intrinsic material thereby increasing a doping efficiency in an ion implantation process, which may improve the rate of dopant atoms being successfully introduced into the bulk or layer of material being doped.
[0048] With reference to FIG. 1, there is shown an example embodiment of strain-assisted doping of phosphorus 102 in diamond 104. In this example, diamond 104 is the intrinsic material and phosphorus 102 is introduced as dopant atoms. Preferably, a tensile strain is applied first to expand the volume of diamond lattice 104, followed by ion-implantation of phosphorus 102. The tensile strain is removed after doping is finished so as to restore the crystal volume or the lattice constant to an original value of the intrinsic material diamond 104.
[0049] Specifically, as shown in FIG. 1, during the doping process, where elastic strain engineering is employed, e.g. the diamond layer 104 may be applied with tensile strain using a strain-locking device, which may effectively secure the strain while ensuring a precise value is applied. When tensile strain is applied, the lattice constant (crystal volume) may be increased temporarily. Then, ion implantation of phosphorus 102 is conducted. The expanded volume of the diamond lattice 104 facilitates the ion implantation process and allows a higher doping concentration of phosphorus 102. Because the deformation of diamond is elastic, the lattice structure can be relaxed to the strain-free state and the intrinsic superior properties of diamond can be maintained. For the doping of diamond, the implanted elements include boron (for p-type doping) , phosphorus (for n-type doping) and nitrogen (for n-type doping, and as part of the process for the preparation of nitrogen vacancy center for quantum applications) .
[0050] Preferably, the tensile strain is applied to the wafer of the intrinsic material along the
[0111] crystalline orientation. To apply strain along the
[0111] direction, it may be preferable to first identify the
[0111] orientation of the diamond wafer (e.g., using transmission electron microscopy) , then the tensile strain may be applied and fixed using a strain-locking device, and in turn temporally increases the lattice constant of the intrinsic material.
[0051] FIG. 2 shows formation energy change of phosphorus doping of diamond with tensile strain applied according to one embodiment of the present invention. The decreased formation energy (the right part) indicates that tensile strain facilitates the doping process. As shown in FIG. 2, with tensile strain applied from 0 to 11 %, the formation energy of phosphorus in diamond decreases. Formation energy reflects whether it is easy or difficult to dope an element into a material. Therefore, it can be seen that tensile strain makes the doping process easier to take place.
[0052] The inventors devised that the formation energy of phosphorus in diamond without strain is 3.17 eV. When a tensile strain of 11%is applied along
[0111] direction, the formation energy is reduced to -0.28 eV, meaning that the doping efficiency can be improved more than 100%.
[0053] Because of the relatively larger bonding length between carbon atoms, doping-induced lattice distortion should be less compared with the ion-implantation without strain. Although large tensile strain helps improve doping efficiency, the setup of high strain may require higher cost. To balance the cost and the performance, according to one embodiment of the present invention, the strain values applied to diamond are preferred to be from 0 to 9%, which can be achieved by experimental observation.
[0054] It may also be observable that this invention is effective for various lattice directions, such as the three most common orientations:
[0100] ,
[0101] , and
[0111] . Alternatively, the method of strain-assisted doping may also be applicable to other directions / orientations.
[0055] FIG. 3 shows schematic drawings of the method 300 of stain-assisted doping of diamond according to one embodiment of the present invention. Diamond, as a deposited layer 302 fixed on substrate layer 304 is elastically stretched first, followed by ion implantation 306. The strain is removed after implantation process is completed. With the use of photoresist (PR) 308 and by adjusting the ion-implantation time, a specific dose of dopant can be introduced into a specific region 302A of diamond.
[0056] Specifically, as illustrated in FIG. 3, it shows how strain engineering is carried out for diamond doping. In this example, diamond is fixed onto a substrate material (which can be silicon, tungsten, or any material with high modulus) . While the substrate material is stretched, tensile strain is applied to diamond wafer, followed by ion implantation. Advantageously, the high modulus facilitates effective strain application. While silicon and tungsten serve only as substrates, and diamond remains the semiconductor material.
[0057] Preferably, the implanted elements can be boron, phosphorus and even more. With the stretching of diamond, the doping efficiency can be improved, and with less damage from the ion to the diamond lattice. As appreciated by a skilled person in the field, reducing damage of a lattice structure may also be beneficial as carrier mobility may also be degraded by defects such as dislocation of atoms in the lattice structure.
[0058] In addition, selective doping only within a doped region of the layer of intrinsic material may be enabled by the ion-implantation process, comparing with thermal diffusion either during epitaxial growth of the intrinsic material or after the layer of intrinsic material had been deposited, with appropriate mask layer applied and patterned above the layer of intrinsic material being deposited.
[0059] It should be appreciated by a skilled person in the art that the term “intrinsic material” in this disclosure refer to pure forms of material without significant impurities or doping, and it has substantially equal number of electron and holes (i.e. n-type and p-type carriers) responsible for electrical conductivity. It should also be appreciated that “intrinsic” is relative to “doped” or “heavily doped” material when comparing the electrical / material properties of each of the doped and intrinsic materials in concern. For example, in semiconductor materials, intrinsic semiconductors are made from pure elements, such as silicon (Si) or germanium (Ge) , without any intentional addition of impurities. Intrinsic semiconductor has the number of electrons in the conduction band is equal to the number of holes in the valence band, therefore the electrical conductivity of intrinsic semiconductors is relatively low compared to doped (extrinsic) semiconductors. This is because the number of charge carriers is limited by the material's intrinsic properties. Accordingly, intrinsic material doesn’ t necessarily absolutely free from impurities as appreciated by a person skilled in the art.
[0060] In addition, the strain-assisted ion implantation method may be used for increasing dopant concentrations within a doped region of a semiconductor material which has been doped. For example, the layer of intrinsic material here may refer to a relatively lower dopant concentration, e.g. 1015 cm-2 of phosphorous in bulk silicon which may be subsequently doped using the strain-assisted doping method in accordance to embodiments of the present invention to define a heavily doped region of 1018 cm-2 of phosphorous near the surface of the silicon substrate / wafer.
[0061] The term “wafer” and “substate” is used in the disclosure, "wafer" refers to the main semiconductor material to be doped, and "substrate" denotes the supporting layer for the semiconductor material. It should also be appreciated that in some alternative embodiments of the present invention, the intrinsic material being doped in the ion implantation process may itself also provided as the substrate layer, e.g. an intrinsic / semi-insulating silicon substrate may be used as both the substrate and electronic devices may be built directly on the substrate in an alternative embodiment of the present invention.
[0062] During the doping process, mask material such as photoresist (PR) can be employed, which will achieve doping of a specific small region, e.g. after appropriate PR patterning and developing process. As shown in the FIG. 3, only the exposed region 302A is doped. By adjusting the PR position and ion implantation time, doping of a specific region of an accurate dose and depth can be achieved. After ion implantation is finished, the elastic tensile strain can be removed.
[0063] In this example, after defining and doping of a doped region 302A of an intrinsic material doped with dopant atoms using the strain-assisted doping method, an electronic device including two or more electrodes disposed on the layer of intrinsic material may be fabricated. For example, the electronic device may comprise a source electrode, a drain electrode and a gate electrode, wherein the gate electrode is disposed above the doped region 302A and between the source electrode and the drain electrode.
[0064] It is important to note that semiconductor materials may be provide in monocrystalline form, as they are more stable and suitable for semiconductor applications. However the strain-assisted doping method can also be applied to non-monocrystalline materials, such as polycrystalline materials or composites, potentially improving doping efficiency. For example, polycrystalline silicon as source / drain electrodes in CMOS devices may also be doped using the strain-assisted doping method in accordance with embodiments of the present invention.
[0065] FIGs. 4A and 4B show a schematic drawing and process flow of ion-implantation process in the strain-assisted doping method according to one embodiment of the present invention. Firstly, a specific type of ion is generated from the ion source 402. Then, the ion is accelerated by the electrodes 404 and impinges on the surface of the strained samples 406, i.e. the layer of intrinsic material deposited on a substrate. The ion-implantation chamber is connected with vacuum system 408 to ensure a low-pressure environment (~10-10 -10-5 mba) which is necessary for this process. In one example embodiment, the ion-implantation process may be carried at room temperature (~300 K) .
[0066] Preferably, the dopant atoms may be activated by high-temperature annealing. For example, a high-temperature and vacuum annealing may be implemented after the ion-implantation, at ~ 1100 K and ~10-10 -10-5 mba, to activate the dopant atoms and repair any possible damage to the crystal matrix during ion-implantation. Advantageously, high-temperature annealing activates the dopant atoms and repairs potential crystal damage. In addition, since strain-assisted doping can expand material volume and minimize crystal damage, it should also facilitate the annealing process, and thereby reducing the required annealing time.
[0067] Preferably, in one example embodiment, the intrinsic material comprises a layer of intrinsic wafer disposed on a substrate layer, e.g. a diamond wafer may be grown or deposited on a piece of semi-insulating silicon (111) wafer as the substrate layer using chemical vapor deposition.
[0068] With reference also to Figures 5 and 6, the process of strain-assisted doping of diamond preferably comprises at least the four key steps as below: Step 502: High-quality single-crystal diamond is prepared by chemical vapor deposition (CVD) , preferably by microwave plasma assisted CVD. Depending on the growth time, diamond wafers can be prepared of various sizes (from 1 to 8 inch) . This is a standard method. Step 504: Using the provided strain-assisted doping strategy, dopant such as boron (for p-type doping) , phosphorus (for n-type doping) and nitrogen (for n-type doping, and as part of the process for the preparation of nitrogen vacancy center for quantum applications) is doped into diamond. Step 506: After doping of diamond is finished, strain is removed. Step 508: High-temperature annealing is conducted, at ~ 1100 K and ~ 10-10 –10-5 mba, to activate the dopant atoms and repair any possible damage to the crystal matrix during ion-implantation.
[0069] Such a strategy of strain-assisted doping can be used not only for the n-type doping of diamond, but also for the p-type doping of diamond and doping of other semiconductor materials such as silicon, gallium nitride, and silicon carbide. The strain-assisted doping method for other semiconductor materials would be similar to that of diamond, but there would be some differences (dopant atoms and strain values) as follows: · Silicon: the dopant atoms include boron (for p-type doping) , phosphorus (for n-type doping) and arsenic (for n-type doping) . The preferred strain for silicon is 0 -16%; · Gallium nitride: the dopant atoms include magnesium (for p-type doping) , silicon (for n-type doping) and germanium (for n-type doping) . The preferred strain for gallium nitride is 0 -14%; and · Silicon carbide: the dopant atoms include aluminum (for p-type doping) , nitrogen (for n-type doping) and phosphorus (for n-type doping) . The preferred strain for silicon carbide is 0 -15%.
[0070] In these alternative examples, the elastic tensile strain limits for Si, GaN, and SiC are 16%, 14%, and 15%, and thus the maximum value of tensile strain applied may be preferably capped at these levels to avoid inducing damage to the lattice structure of the doped material.
[0071] Advantageously, the present invention provides a method of preparing doped diamond by applying stretching during dopants are implanted. Embodiments of the present invention is different from alternative approach of applying strain to a layer of semiconductor in an electronic device for enhancing carrier mobility. For example strain engineering may be applied where dopants such as boron, nitrogen and phosphorus may be introduced. However, the purpose of performing strain engineering in a fabricated layer is different.
[0072] Different from strain-assisted doping in accordance with embodiments of the present invention, strain engineering may be applied to modulate the electrical properties of the boron-, nitrogen-, or phosphorus-doped diamond (i.e., to stretch or compress a diamond that is already doped with these elements) of a layer of material, however strain engineering has nothing to do with the doping process.
[0073] To better understand a fundamental different between strain engineering and strain-assisted doping, it should be understood that Strain engineering is a technique used to enhance the performance of semiconductor devices by improving carrier mobility, e.g. by altering atomic lattice structure and modify energy band structure which may lead to a reduction in effective mass of the charge carriers (electrons and holes) , which in turn increases their mobility. In addition, strain in semiconducting material may also reduce the scattering of charge carriers by altering the phonon spectrum and reducing the interaction between charge carriers and phonons. This leads to less resistance and higher mobility. With improved carrier mobility, the semiconductor devices can operate at higher speeds and with greater efficiency.
[0074] In contrast, in the present invention, it is to employ strain to facilitate the doping process, which is more related with how to prepare the doped diamond and make the device of high-quality.
[0075] If doped elements are introduced into diamond without strain / stress, then the material is stretched / compressed, it would be entirely different from applying strain to the doped material during the doping process. The applied process includes steps: (1) firstly stretch the diamond and then (2) dope the elements via ion implantation. which in turn improve the doping efficiency and thus enhancing the carrier mobility of the layer after the dopants are activated, whereas applying strain after doping process may only change the electrical properties, specifically carrier mobility, of diamond, it is only to stretch the diamond and free from compressing, because compressing doesn’ t help the doping process nor increasing the dopant concentration or doping efficiency within the layer of doped semiconducting material.
[0076] The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art.
[0077] The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated.
Claims
1.A method for doping of a material, comprising the steps of:providing a wafer of an intrinsic material;temporally increasing a crystal volume or a lattice constant of the intrinsic material thereby increasing a doping efficiency in an ion implantation process;performing ion implantation on the wafer to introduce dopant atoms into the wafer with the increased crystal volume or lattice constant;restoring the crystal volume or the lattice constant to an original value of the intrinsic material; andactivating the dopant atoms within the wafer.2.The method of Claim 1, wherein the intrinsic material includes a semiconductor material.3.The method of Claim 2, wherein the wafer is provided on a substrate having a high modulus mechanical property.4.The method of Claim 3, wherein the step of temporally increasing the crystal volume or the lattice constant comprising the step of deforming the wafer by applying tensile strain with a predetermined strain value to the wafer.5.The method of Claim 4, wherein the tensile strain is applied to the intrinsic material along the [111] crystalline orientation.6.The method of Claim 4, wherein the predetermined strain values of the tensile strain applied to a diamond wafer ranges from 0 to 9%.7.The method of claim 6, wherein the dopant atoms comprise phosphorus for n-type dopants of the diamond wafer or boron for p-type dopants of the diamond wafer.8.The method of Claim 4, wherein the predetermined strain values of the tensile strain applied to a gallium nitride wafer ranges from 0 to 14%.9.The method of Claim 8, wherein the dopant atoms comprise germanium / silicon for n-type dopants of the gallium nitride wafer, or magnesium for p-type dopants of the gallium nitride wafer.10.The method of Claim 4, wherein the predetermined strain values of the tensile strain applied to a silicon wafer ranges from 0 to 16%.11.The method of Claim 10, wherein the dopant atoms comprise phosphorus / arsenic for n-type dopants of the silicon wafer, or boron for p-type dopants of the silicon wafer.12.The method of Claim 4, wherein the predetermined strain values of the tensile strain applied to a silicon carbide wafer ranges from 0 to 15%.13.The method of Claim 12, wherein the dopant atoms comprise phosphorus / nitrogen for n-type dopants of the silicon carbide wafer, or aluminium for p-type dopants of the silicon carbide wafer.14.The method of Claim 1, wherein the dopant atoms are activated by high-temperature annealing.15.The method of Claim 3, wherein the wafer of the intrinsic material is fixed on the substrate layer.16.The method of Claim 15, further comprising the step of defining a doped region for ion implantation such that the dopant atoms are introduced to only within the doped region of the layer of intrinsic material.17.The method of Claim 15, wherein the step of providing a wafer of an intrinsic material comprises the step of depositing the layer of intrinsic material on the substrate layer using chemical vapor deposition.18.A method of fabricating an electronic device, comprising the step of:- preparing a wafer having a doped region of an intrinsic material doped with dopant atoms according the method of Claim 16, and- fabricating the electronic device including two or more electrodes disposed on the layer of intrinsic material.19.The method of claim 18, wherein the electronic device comprises a source electrode, a drain electrode and a gate electrode, wherein the gate electrode is disposed above the doped region and between the source electrode and the drain electrode.20.An electronic device comprising a layer of intrinsic material processed by the method in accordance with Claim 18.
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