Ion implantation system with resonator, linear accelerator configuration and toroidal resonator

Abstract

The device may include a drift tube assembly arranged to transmit an ion beam. The drift tube assembly may include a first ground electrode; an RF drift tube assembly disposed downstream of the first ground electrode; and a second ground electrode disposed downstream of the RF drift tube assembly. The RF drift tube assembly may define a triple gap configuration. The device may include a resonator, the resonator includes a toroidal coil, the toroidal coil having a first end connected to a first RF drift tube of the RF drift tube assembly and a second end connected to a second RF drift tube of the RF drift tube assembly.

Description

Technology Field

[0001] The present disclosure generally relates to ion implantation devices, and more specifically to high-energy beamline ion implanters. Background Technology

[0002] Ion implantation is a process of introducing dopants or impurities into a substrate through ion bombardment. Ion implantation systems may include an ion source and a series of beamline components. The ion source may include a chamber where ions are generated. The ion source may also include an extraction electrode assembly and a power source positioned adjacent to the chamber. Beamline components may include, for example, a mass spectrometer, a first acceleration or deceleration stage, a collimator, and a second acceleration or deceleration stage. Much like a series of optical lenses for manipulating a light beam, beamline components can filter, focus, and manipulate ions or ion beams having specific species, shapes, energies, and / or other qualities. The ion beam may pass through the beamline components and be directed toward a substrate mounted on a platen or clamp.

[0003] Implantation devices capable of generating ion energies of approximately 1 MeV or higher are often referred to as high-energy ion implanters or high-energy ion implantation systems. One type of high-energy ion implanter is referred to as a linear accelerator, or LINAC, in which a series of electrodes arranged as tubes conduct an ion beam along successive tubes and accelerate it to increasingly higher energies, where the electrodes receive an AC voltage signal. Known (RF) LINACs are driven by RF voltages applied at frequencies between 13.56 MHz and 120 MHz.

[0004] In order to reach a target final energy, e.g., 1 MeV, several MeV, or more, in known LINACs (for brevity, the term LINAC as used herein may refer to an RF LINAC that uses RF signals to accelerate an ion beam), the ion beam can be accelerated in a number of acceleration stages. Each successive stage of the LINAC can receive an ion beam of increasingly higher energy and can accelerate the ion beam to even higher energies.

[0005] Depending on the number of drift tubes (acceleration electrodes), known acceleration stages may adopt a so-called double-gap configuration or a so-called triple-gap configuration. The advantage of the triple-gap configuration is that three acceleration gaps are provided within a given acceleration stage, allowing the accelerated ions to increase their energy by a maximum increase equal to four times the product of the ion charge state and the maximum rf voltage amplitude generated on the electrodes. For comparison, for the same ion species, a double-gap configuration can accelerate the ion beam by up to twice the product of the ion charge state and the maximum rf voltage amplitude on the acceleration drift tubes. Therefore, for a given maximum available driving voltage, a triple-gap configuration can accelerate the ion beam to the target ion energy using fewer acceleration stages than a double-gap configuration.

[0006] Although the use of a triple-gap configuration within a given acceleration stage may present a more efficient configuration than double-gap configurations, the size of the LINACs is still relatively long, partly due to the large resonator components required to generate high rf voltages on the drift tubes (acceleration electrodes).

[0007] The present disclosure is provided in relation to these and other considerations.

[0008] In one embodiment, an apparatus is provided comprising a drift tube assembly arranged to transmit an ion beam. The drift tube assembly may include a first ground electrode; an RF drift tube assembly disposed downstream of the first ground electrode; and a second ground electrode disposed downstream of the RF drift tube assembly. By doing so, the RF drift tube assembly may define a triple-gap configuration. The apparatus may also include a resonator comprising a toroidal coil, wherein the toroidal coil has a first end connected to a first RF drift tube of the RF drift tube assembly and a second end connected to a second RF drift tube of the RF drift tube assembly.

[0009] In another embodiment, an ion implanter is provided comprising an ion source for generating an ion beam and a linear accelerator for transporting and accelerating the ion beam, wherein the linear accelerator comprises a plurality of acceleration stages. A given acceleration stage among the plurality of acceleration stages may comprise an RF power assembly arranged to output an RF signal and a drift tube assembly arranged to transmit an ion beam and coupled to the RF power assembly, wherein the drift tube assembly defines a triple-gap configuration. A given acceleration stage may further comprise a resonator comprising a toroidal coil, wherein the toroidal coil has a first end connected to a first RF drift tube of the drift tube assembly and a second end connected to a second RF drift tube of the drift tube assembly.

[0010] In another embodiment, a resonator for a linear accelerator is provided. The resonator may include an RF enclosure and a toroidal coil disposed within the RF enclosure. The toroidal coil may include a first half forming a first coil having a first plurality of turns wound in a first direction; and a second half forming a second coil having a second plurality of turns wound in the first direction. Thus, the first half may further include a first end for coupling to a first electrode of the linear accelerator, and the second half may further include a second end for coupling to a second electrode of the linear accelerator. The resonator may also include an exciter coil disposed within the toroidal coil, and the exciter coil has a first leg connected to ground and a second leg coupled to receive RF power. Brief explanation of the drawing

[0011] FIG. 1 illustrates an exemplary apparatus according to embodiments of the present disclosure; FIG. 2 presents a detailed front view of an embodiment of a toroidal coil; FIGS. 3a, 3b, and 3c respectively illustrate a side view, a perspective view, and a front view of an acceleration stage according to embodiments of the present disclosure; FIG. 4a illustrates an exciter coil according to embodiments of the present disclosure; FIG. 4b illustrates the exciter coil of FIG. 4a within an exemplary toroidal coil; FIG. 4c illustrates an embodiment of a tuner for a resonator according to embodiments of the present disclosure; FIG. 4d illustrates the dependence of the resonant frequency on the tuner structure of FIG. 4c; FIGS. 5a-5d illustrate the electrical characteristics of a toroidal resonator coil employed as a triple-gap configuration resonator according to embodiments of the present disclosure; FIG. 5e presents a simulation of the electromagnetic characteristics of a resonator coil arranged according to embodiments of the present disclosure; FIGS. 6a and 6b illustrate alternative embodiments of a toroidal coil for use as a resonator according to different embodiments of the present disclosure; FIG. 7 illustrates the dependence of coil tube diameter versus tube length for the coil embodiment shown in FIG. 6b; FIGS. 8a-8c respectively illustrate a side view, a perspective view, and a front view of a toroidal coil according to embodiments of the present disclosure; FIGS. 9a and 9b illustrate alternative configurations of a toroidal resonator according to different embodiments of the present disclosure; FIG. 10 illustrates a schematic diagram of an ion implanter device according to embodiments of the present disclosure. The drawings are not necessarily in scale. They are merely representations and are not intended to depict specific parameters of the present disclosure. The drawings are intended to illustrate exemplary embodiments of the present disclosure and should not be construed as limiting the scope. In the drawings, similar numbers indicate similar elements. Specific details for implementing the invention

[0012] Now, the apparatus, system, and method according to the present disclosure will be described more fully below with reference to the accompanying drawings, in which embodiments of the system and method are illustrated. The system and method may be implemented in many different forms and should not be construed as being limited to the embodiments presented herein. Rather, such embodiments are provided to ensure that the present disclosure is thorough and complete, and to fully convey the scope of the system and method to a person skilled in the art.

[0013] In this document, terms such as "top," "bottom," "top," "bottom," "vertical," "horizontal," "lateral," and "longitudinal" may be used to describe the geometry and orientation of components of a semiconductor manufacturing device as shown in the drawings, and the relative arrangement and orientation of these components and their constituent parts. The terms may include specifically mentioned words, their derivatives, and words of similar meaning.

[0014] As used herein, elements or operations referred to in the singular and preceded by a singular word are understood to potentially include plural elements or operations. Furthermore, references to "one embodiment" in this disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also include the mentioned features.

[0015] Approaches to improved high-energy ion implantation systems and components based on beamline architecture, in particular, ion implanters based on linear accelerators, are provided herein. For brevity, ion implantation systems may also be referred to herein as "ion implanters." Various embodiments involve novel approaches that provide the ability to flexibly adjust the effective drift length within the acceleration stages of a linear accelerator.

[0016] FIG. 1 illustrates an exemplary apparatus of a first configuration according to embodiments of the present disclosure. The apparatus (100) represents an acceleration stage comprising a drift tube assembly (102) and an associated resonator (110) for accelerating an ion beam (104) in a linear accelerator. As illustrated in FIG. 10, which is discussed below, the apparatus (100) may be implemented as a plurality of acceleration stages of a linear accelerator (314) for accelerating an ion beam (306) in an ion implanter (300).

[0017] In the embodiment of FIG. 1, the drift tube assembly (102) comprises an upstream grounded drift tube and a downstream grounded drift tube, labeled similarly to grounded drift tube electrodes (102B). The drift tube assembly (102) further comprises a pair of RF drift tube electrodes separated by a gap between them, illustrated as RF drift tube electrodes (102A). Collectively, the RF drift tube electrodes (102A) and the grounded drift tube electrodes (102B) define a triple-gap configuration.

[0018] The resonator (110) includes an rf enclosure (can) (112) to house a toroidal coil (114) and to form an electric oscillating circuit through the generated coil-enclosure electrostatic capacitance. The toroidal coil (114) and similar resonator coils are described in detail in the following embodiments. Briefly, FIG. 2 presents a detailed front view of an embodiment of the toroidal coil (114). As used herein, the term “toroidal coil” may refer to two distinct coils arranged relative to define a toroidal shape, wherein each of the distinct coils may form a part of the toroidal shape, e.g., similar halves of the toroid.

[0019] As illustrated in FIG. 2, the toroidal coil (114) comprises a plurality of loops or turns. The toroidal coil (114) comprises two coils arranged in two halves, each having N turns and composed of a suitable conductor such as copper tubing. As illustrated in FIG. 2, the turns of each half of the toroidal coil (114) are wound in the same direction. In the upper portion of the toroidal coil (114), the two ends of the toroidal coil (114) are extended by a length (10) and pass through an opening of the RF enclosure (can) to allow for separate connections to the two separate powered RF drift tube electrodes described above and for further integration in the enclosure. In the bottom portion, the loops of the toroidal coil (114) are connected to a grounded can wall.

[0020] A toroidal coil (114) is powered by an exciter coil (116) and is positioned symmetrically between the grounded legs of the toroidal coil (114). An insulating sleeve (118) ensures electrical insulation between the powered legs of the exciter coil and the grounded can wall. The exciter coil (116) is arranged to receive RF power as part of an RF power assembly, illustrated as an RF circuit (124) comprising an RF generator (120) and an impedance element (122). The resonator (110) further comprises a tuner (130), and the tuner may be arranged as a capacitive structure, as described in detail below.

[0021] The device (100) differs from known triple-gap accelerator stages in that the resonator (110) transmits voltage to the drift tube assembly (102) through a toroidal coil (114), in contrast to the solenoid (or helical) coils of known triple-gap accelerator stages. As discussed in more detail in relation to FIGS. 5a-5d, the toroidal coil resonator structure of FIG. 1 benefits from the fact that magnetic flux is contained within the toroidal coil (114), avoiding leakage of the line of force outside the toroidal coil (114), and thus leading to fewer eddy currents induced in the rf enclosure (112) of the resonator.

[0022] FIGS. 3A, FIGS. 3B, and FIGS. 3C respectively illustrate a side view, a perspective view, and a front view of an acceleration stage (200) according to embodiments of the present disclosure. The acceleration stage includes insulating holders (128) as well as a drift tube electrode assembly arranged in a triple-gap configuration within an ion beam housing (126). The acceleration stage (200) further includes a resonator (210) comprising the toroidal coil (114) described above. The resonator (210) further includes a tuner (130), and the tuner (130) includes a tuner body disposed in a first portion and a second portion, respectively, along a first side of the toroidal coil (114) and a second side of the toroidal coil (114). Details of an embodiment of the tuner (130) are illustrated in FIG. 4C and are discussed in detail below. Briefly, the tuner (130) may be movable along the main axis of the toroidal coil (114), which is illustrated as the x-axis in the illustrated Cartesian coordinate system. The movement of the tuner (130) along the X-axis may change the capacitance of the electric RLC circuit limited by the resonator (210), thereby allowing the resonant frequency of the resonator (210) to be adjusted.

[0023] According to embodiments of the present disclosure, FIG. 4a illustrates an exciter coil (116), while FIG. 4b illustrates an exciter coil (116) placed within a toroidal coil (114). The exciter coil (116) may have a first leg (right leg) connected to ground and a second leg (left leg) coupled to an RF power assembly. As shown in FIG. 4a, the leg of the exciter coil (116) coupled to the RF power assembly may be insulated from the RF enclosure (112) by an insulating sleeve (118).

[0024] In various embodiments, the exciter coil (116) is a single-turn loop made of metal tubing, such as copper tubing, for fluid cooling. The loop diameter (d) can be arranged to be approximately equal to the radius of the toroidal coil (114). The angle of the angled opening (θ) can be between 15 and 20 degrees and is set according to the spatial separation required to prevent arcing on the grounded leg of the toroidal coil (114). To maximize the mutual coupling coefficient (M) between the exciter coil and the toroidal coil, the exciter coil plane (in this case, the XY plane) can be arranged perpendicular to the azimuth axis of the toroid defined by the toroidal coil (114), centered on this axis, and placed at an intermediate distance between the last grounded side loops of the toroidal halves, as also illustrated in FIG. 3a and 3b.

[0025] Now, referring to FIG. 4c, an embodiment of a tuner (130) comprising first and second half sections, illustrated as crowns (130A), arranged to be on opposite sides of a toroidal coil (114) is shown. In this embodiment, the crowns (130A) are arranged as toroidal crowns that mimic the shape of the toroidal coil (114). A cross-shaped holder (130B) is attached to each of the half sections, while also being attached to the rods (130C). The rods (130C) can be mounted on a guide stage (not shown) and pass through the rf enclosure (112). The rods (130C) can be driven from outside the rf enclosure (112) by a mechanism, such as an electric linear motion stage, which can translate the rods (130C) along the x-axis. In one embodiment, to maximize the tuning range, the radius of curvature of the crowns (130A) may be set to be equal to the negative radius of the torus forming the toroidal coil (114); in an embodiment, the height (h) of the crown (130A) may be slightly greater than 2r, which is the negative diameter of the toroid. The tuner (130) may be set to ground potential so that the toroidal coil-toroidal crown assembly forms an electrical circuit or system formed by two capacitors connected in parallel. As the coil-to-crown distance increases, the capacitance decreases, leading to an increase in the resonant frequency.

[0026] In various non-limiting embodiments, the features of the toroidal resonator are designed so that the operating resonant frequency matches the operating frequency of a suitable RF power supply or RF generator, e.g., 13.56 MHz. Since the cavity containing the toroidal coil forms an RLC circuit, the circuit,

[0027] (1)

[0028] It will vibrate at a specific frequency f0 having a value at resonance given by, where L is the inductance of the coil and C is the capacitance of the system.

[0029] Referring to FIG. 4d, the dependence of the resonant frequency on the tuner structure of FIG. 4c is shown as a function of changing the position of the crowns (130A). As shown in FIG. 4d, for a translation of 50 mm from x=100 mm to x=150 mm from the azimuth plane (Oyz), the tuner (130) produces a tuning range greater than 1.5 MHz around a desired frequency of 13.56 MHz.

[0030] Refer to FIGS. 5a-5d, which illustrate the electrical characteristics of a toroidal resonator coil employed as a resonator in a triple-gap configuration according to embodiments of the present disclosure. In FIG. 5a, an rf current (current shown by dark arrows) traveling through an exciter coil (116) at a given moment during an rf cycle is illustrated. The rf power applied to the input of the exciter coil (116) will generate an rf current (152), and the current will further generate a local time-varying magnetic field. As illustrated in FIG. 5b, mutual coupling between the exciter coil (116) and the toroidal coil (114) allows the magnetic flux lines (154) to be closed through the volume of the toroidal coil (114). Since rf power is transferred from the rf generator through the exciter coil to an electric oscillating circuit, the magnetic energy of the toroidal coil (114) is,

[0031] (2)

[0032] Here, B is the magnetic field strength of the coil, μ0 is the permeability of vacuum, and electrostatic energy

[0033] (3)

[0034] It will be periodically converted, where ε0 is the permittivity of vacuum and E is the electrostatic field at the ends of the toroidal coil (114) at the top of the drawing. The voltage generated at the RF drift tube electrodes (102A) creates electrostatic equipotential lines (156) in the three gaps between the RF drift tube electrodes (102A) and the grounded drift tube electrodes (102B), where the electric field vectors (158) are shown in FIG. 5d. As is known, the electric field thus formed will oscillate according to the frequency of the applied RF signal. By applying precise timing of the arrival of ions of the pulsed or focused ion beam at the entrance of the acceleration gaps, the ions can obtain energy equal to up to four times the product of the charge and the RF voltage amplitude.

[0035] FIG. 5e presents a simulation of the electromagnetic properties of a resonator coil arranged according to embodiments of the present disclosure. In the figure, B(t) represents a variable magnetic flux in the resonator coil, while V1(t) is a variable rf voltage on a first powered electrode coupled to one end of the resonator coil, and V2(t) is a variable rf voltage on a second powered electrode coupled to the second end of the resonator coil. The temporal variation of the magnetic flux and rf voltages on the electrodes is described by an rf phase equal to 2πf0t, where t is elapsed time. The magnetic flux may represent a flux flowing through the volume of a toroidal coil at a given moment. During half of the rf cycle, the flux will be oriented in one direction, e.g., clockwise, and during the next half period, the flux will be oriented counterclockwise.

[0036] As can be seen, there is a phase difference of π / 2 radians (equivalent to 90 degrees) between the voltages on the electrodes and the magnetic field. According to equations (2) and (3), the magnetic energy is zero when the electrostatic energy is maximum, and vice versa. Additionally, there is a phase difference of π radians between the voltages on the powered electrodes; therefore, the voltage on one electrode is +V 최대 When that, the voltage on the other electrode is -V 최대 am.

[0037] FIGS. 6a-6b and FIG. 7 illustrate alternative embodiments of a toroidal coil for use as a resonator according to different embodiments of the present disclosure. The toroidal coil (114A) of FIG. 6a may be composed of an electrically conductive tube having a constant tube diameter (meaning constant tube diameter), wherein the diameter is denoted as Φ for the sake of simplicity of construction, and the pitch between adjacent turns in the inner portion of the toroidal coil (114A) is defined as p. Since the RF current through the toroidal coil (114A) may be limited to a skin depth of approximately less than 20 micrometers for frequencies in the 13.56 MHz range, the thickness of the walls of the conductive tube does not need to be thicker than 50 micrometers, 100 micrometers, etc. However, to provide mechanical rigidity to the coil and prevent mechanical vibrations, tube walls with a thickness of several mm are used.

[0038] The toroidal coil (114B) of FIG. 6b may be composed of an electrically conductive tube having a continuously variable diameter, the outer tube diameter (Φ) along the outer side of the toroidal coil (114B) having a first dimension, and the inner tube diameter (Φ') along the inner side of the toroidal coil (114B) having a second dimension smaller than the first dimension. The result of this latter configuration is that the value of p is relatively larger than that of the embodiment of FIG. 6a, and thus the electric field between adjacent turns of the toroidal coil (114B) is relatively smaller. This lower electric field can help avoid arcing. In certain embodiments, as the tubing bends toward the inner part of the toroidal coil (114C), the diameter of the tube may be continuously reduced so that the tube has a minimum diameter at the inner positions of the toroidal coil, resulting in an increase in pitch to a larger value of p'. Additionally, a larger pitch implies smaller interloop capacitance and a resulting higher quality (Q) factor of the oscillating circuit.

[0039] (4)

[0040] It is noted that in variations of the aforementioned embodiments, the shape of the individual turns of the toroidal coil may be characterized by an elliptical cross section, e.g., a circular cross section. As shown in FIG. 7, a continuously variable diameter tubing is used to construct the coil shown in FIG. 6b, and the tubing has a maximum diameter (d) at the outermost positions of the coil. 최대 having ) and minimum diameter (d) at the innermost positions 최소 It has ) and has a periodicity of 2πr along the tube length.

[0041] FIGS. 8a, 8b, and 8c respectively illustrate a side view, a perspective view, and a front view of a toroidal coil (114C) according to embodiments of the present disclosure. In this example, the toroidal coil features coil turns defining a D-shaped cross section. Such a D-shaped cross section will increase the total volume within the toroidal coil compared to a toroidal coil having coil turns defined by a circular cross section, considering the same main diameter and the same coil turn diameter.

[0042] FIGS. 9a and 9b illustrate alternative configurations of a toroidal resonator according to different embodiments of the present disclosure. Due to azimuthal half-symmetry, the toroidal geometry is highly versatile for being arranged into different configurations: this versatility will allow for the minimization of the resonator footprint. Configuration (250) illustrates a housing (212) in which the beam direction (along the Z-axis) moves in and out of the plane of the drawing. Configuration (260) also illustrates a housing (212) in which the beam direction (along the Z-axis) moves in and out of the plane of the drawing. As illustrated, the axis of the toroidal coil of the resonator (210) is aligned along the X-axis. When the resonators are aligned along the Z-axis, the configuration (250) illustrated in FIG. 9a is preferred (the height of the can resonator is generally smaller than the diameter). Conversely, when the resonators are distributed in both the z-direction and the azimuth direction, the configuration (260) shown in FIG. 9b is preferred.

[0043] FIG. 10 illustrates a schematic diagram of an apparatus according to embodiments of the present disclosure. The ion implanter (300) includes a linear accelerator (314). The ion implanter (300) may represent a beamline ion implanter, and for clarity of description, some elements are not illustrated. The ion implanter (300) may include an ion source (302) and a gas box (307), as is known in the art. The ion source (302) may include an extraction system comprising extraction components and filters (not illustrated) to generate an ion beam (306) with a first energy. Examples of ion energies suitable for the first ion energy are in the range of 5 keV to 300 keV, while embodiments are not limited to this context. To form a high-energy ion beam, the ion implanter (300) includes various additional components for accelerating the ion beam (306).

[0044] The ion implanter (300) may include an analyzer (310) that functions to analyze the ion beam (306) as in a known device by changing the trajectory of the ion beam (306) as illustrated. The ion implanter (300) may also include a collector (312) and a linear accelerator (314) (illustrated by dashed lines) positioned downstream of the collector (312), wherein the linear accelerator (314) is arranged to accelerate the ion beam (306) to form a high-energy ion beam (315) greater than the ion energy of the ion beam (306) before it enters the linear accelerator (314). The collector (312) may receive the ion beam (306) as a continuous ion beam and output the ion beam (306) to the linear accelerator (314) as a collected ion beam. The linear accelerator (314) may include a plurality of acceleration stages represented by resonators (110) arranged in series, as illustrated. In various embodiments, the ion energy of the high-energy ion beam (315) may represent the final ion energy, or approximately the final ion energy, for the ion beam (306). In various embodiments, the ion implanter (300) may include additional components, such as a filter magnet (316), a scanner (318), and a collimator (320), wherein the general functions of the scanner (318) and the collimator (320) are well known and will not be described in further detail herein. Thus, the high-energy ion beam represented by the high-energy ion beam (315) can be delivered to a terminal station (322) to process a substrate (324). The non-limiting energy range for the high-energy ion beam (315) includes 500 keV - 10 MeV, wherein the ion energy of the ion beam (306) is increased stepwise through various acceleration stages of the linear accelerator (314). According to various embodiments of the present disclosure, the acceleration stages of the linear accelerator (314) are powered by resonators (110), and the design of the resonators (110) may follow the embodiments of FIG. 1-9b.

[0045] With the foregoing in mind, the present disclosure provides at least the following advantages. Regarding one advantage, a smaller resonator footprint can be realized by using the toroidal coil resonator of the embodiments, and accordingly, a smaller LINAC footprint can be realized compared to known LINAC-based ion implanters. The embodiments further provide the advantage of a higher quality factor (Q) of the vibration circuit compared to solenoid-type resonators.

[0046] Although specific embodiments of the present disclosure have been described herein, the present disclosure is not limited thereto, as the scope of the present disclosure is broad as the art would allow, and the present specification can be read as such. Therefore, the above description should not be interpreted as a limitation. A person skilled in the art will conceive other modifications within the scope and spirit of the appended claims.

Claims

Claim 1 A device comprising: a drift tube assembly arranged to transmit an ion beam, wherein the drift tube assembly comprises: a first ground electrode; an RF drift tube assembly disposed downstream of the first ground electrode; and a second ground electrode disposed downstream of the RF drift tube assembly, wherein the RF drift tube assembly defines a triple gap configuration; a resonator, wherein the resonator comprises a toroidal coil, wherein the toroidal coil has a first end connected to a first RF drift tube of the RF drift tube assembly and a second end connected to a second RF drift tube of the RF drift tube assembly; and a tuner, wherein the tuner comprises a tuner body, wherein the tuner body is disposed in a first portion along a first side of the toroidal coil and disposed in a second portion along a second side of the toroidal coil. Claim 2 A device according to claim 1, wherein the toroidal coil has a first half and a second half, and the first half includes a first number of turns equal to the second number of turns of the second half. Claim 3 In claim 1, the toroidal coil is a device that defines an elliptical cross-section. Claim 4 In claim 1, the toroidal coil is a device that defines a D-shaped cross-section. Claim 5 In claim 1, the toroidal coil comprises an electrically conductive tube having a constant tube diameter, forming a device. Claim 6 A device according to claim 1, wherein the toroidal coil comprises an electrically conductive tube having a non-uniform tube diameter, the outer tube diameter disposed along the outer side of the toroidal coil has a first dimension, and the inner tube diameter disposed along the inner side of the toroidal coil has a second dimension smaller than the first dimension. Claim 7 delete Claim 8 The device according to claim 1, further comprising an exciter coil disposed inside the toroidal coil, wherein the exciter coil has a first leg connected to ground and a second leg coupled to an RF power assembly. Claim 9 An ion implanter comprising: an ion source for generating an ion beam; and a linear accelerator for transporting and accelerating said ion beam, wherein the linear accelerator comprises a plurality of acceleration stages, and a given acceleration stage among the plurality of acceleration stages comprises: an RF power assembly arranged to output an RF signal; a drift tube assembly arranged to transmit said ion beam and coupled to said RF power assembly, wherein the drift tube assembly defines a triple gap configuration; a resonator, wherein the resonator comprises a toroidal coil, and the toroidal coil has a first end connected to a first RF drift tube of said drift tube assembly and a second end connected to a second RF drift tube of said drift tube assembly; and a tuner, wherein the tuner comprises a tuner body, wherein the tuner body is disposed in a first portion along a first side of said toroidal coil and disposed in a second portion along a second side of said toroidal coil. Claim 10 An ion implanter according to claim 9, wherein the toroidal coil has a first half and a second half, and the first half includes a first number of turns equal to the second number of turns of the second half. Claim 11 In claim 9, the toroidal coil is an ion implanter that defines an elliptical cross-section. Claim 12 In claim 9, the toroidal coil is an ion implanter that defines a D-shaped cross-section. Claim 13 In claim 9, the toroidal coil comprises an electrically conductive tube having a constant tube diameter, an ion implanter. Claim 14 An ion implanter according to claim 9, wherein the toroidal coil comprises an electrically conductive tube having a non-uniform tube diameter, the outer tube diameter disposed along the outer side of the toroidal coil has a first dimension, and the inner tube diameter disposed along the inner side of the toroidal coil has a second dimension smaller than the first dimension. Claim 15 delete Claim 16 An ion implanter according to claim 9, further comprising an exciter coil disposed inside the toroidal coil, wherein the exciter coil has a first leg connected to ground and a second leg coupled to an RF power assembly. Claim 17 A resonator for a linear accelerator, comprising: an RF enclosure; a toroidal coil disposed within the RF enclosure, wherein the toroidal coil comprises: a first half forming a first coil having a first plurality of turns wound in a first direction; and a second half forming a second coil having a second plurality of turns wound in the first direction, wherein the first half further comprises a first end for coupling to a first electrode of the linear accelerator and the second half further comprises a second end for coupling to a second electrode of the linear accelerator—; and an exciter coil disposed within the toroidal coil, wherein the exciter coil has a first leg connected to ground and a second leg coupled to receive RF power. Claim 18 In Clause 17, the toroidal coil is a resonator that defines an elliptical cross-section. Claim 19 In Clause 17, the toroidal coil is a resonator that defines a D-shaped cross-section. Claim 20 A resonator according to claim 17, wherein the toroidal coil comprises an electrically conductive tube having a non-uniform tube diameter, the outer tube diameter disposed along the outer side of the toroidal coil has a first dimension, and the inner tube diameter disposed along the inner side of the toroidal coil has a second dimension smaller than the first dimension.

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