Methods and systems useful for producing aluminum ions

Abstract

To provide a method of generating aluminum ions in an ion source having an ion source chamber.SOLUTION: A method comprises: in an ion source chamber 12 that contains aluminum dopant source, making fluorine-containing gas selected from BF3, PF3, PF5, GeF4, XeF2, CF4B2F4, SiF4, Si2F6, AsF3, AsF5, XeF4, XeF6, WF6, MoF6, CnF2n+2, CnF2n, CnF2n-2, CnHxF2n+2-x, CnHxF2n-x, CnHxF2n-2-x (n=1, 2, 3..., -x=0, 1, 2...), COF2, SF6, SF4, SeF6, NF3, N2F4, HF, F2, or a combination thereof, and hydrogen-containing gas flow into the ion source chamber: and generating aluminum ions within the ion source chamber.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention generally relates to devices, systems, and methods for ion implantation, and more particularly to an ion source useful for generating an aluminum ion beam.

Background Art

[0002] The implantation of aluminum ions into a substrate such as a semiconductor material is used in the fabrication of semiconductor and microelectronic devices. As an example, aluminum has been used as a p-type dopant for doping a portion of the transistor structure of a microelectronic device. For example, aluminum can be implanted into silicon or silicon carbide.

[0003] Ion implantation as practiced in semiconductor manufacturing involves the doping of a substrate, such as a microelectronic device wafer, with a species by the collision of energetic ions of the species with the substrate. To generate ion dopant species, a dopant source, which can be in the form of, for example, a halide or hydride of the dopant species, is ionized. This ionization is performed using an ion source (also known as an "ion source device") to generate an ion beam containing the dopant species. The ion source generates ions within an "ionization chamber" or "arc chamber".

[0004] Past methods of generating aluminum ions by an ion source have generated aluminum ions by combining an aluminum dopant source in an arc chamber with a fluorinated compound, i.e., a "co-gas" (also sometimes referred to as a "carrier gas" or "co-reactant"), where the fluorinated compound is boron trifluoride (BF 3 ) or phosphorus trifluoride (PF 3) It is. Aluminum is introduced into the ionization process as a solid aluminum-containing target material. The fluorinated compound reacts with solid aluminum (including chemical reactions and physical sputtering) to release aluminum from the aluminum target into the arc chamber, where the aluminum is ionized.

[0005] Other solid materials such as tungsten or molybdenum also exist in the arc chamber as structures of the arc chamber. During ionization, the fluorine-containing co-gas is ionized or decomposed in the arc chamber to generate neutral or ionized fluorine-containing species. These fluorine-containing species react with solid materials in the arc chamber other than the solid aluminum target, including tungsten. As a result, ionic tungsten (W + ) or tungsten fluoride compounds (WF x + ) or ionic molybdenum (Mo + ) or molybdenum fluoride compounds (MoF x + ) and other ionic species other than the desired aluminum ions are generated. In the arc chamber, these unwanted non-aluminum ionic species can accumulate as residues in the arc chamber over the service life of the arc chamber. The residues can deposit on operating components such as cathodes, counter cathodes, insulators, or other structures. The deposited substances can cause harmful effects on the performance of the ion source, such as a decrease in beam current over time or a shortening of the ion source life.

[0006] Micro-arcing, sometimes called "glitching," will spread more as an insulator in the extraction electrode or other supply source area components where WF x + or MoF x + residues are deposited. Micro-arcing can result in non-uniformity of the beam hitting the substrate and can affect device yield.

[0007] Fluoride reaction products of refractory metals used in the arc chamber (WF x + or MoF x + ) erosion has detrimental consequences for the arc chamber exit aperture. The arc chamber exit aperture creates the initial ion beam shape as the ion beam travels through the device to the target substrate. The ion beam shape can be distorted by erosion of the aperture due to the transfer of tungsten or molybdenum within the arc chamber. The erosion changes the shape of the exit aperture to an extent that the device cannot compensate for the appropriate beam shape and / or uniformity. This non-uniform beam shape results in non-uniform doping of the substrate and can affect device yield. SUMMARY OF THE INVENTION

[0008] In one aspect, the present invention relates to a method of generating aluminum ions in an ion source having an ion source chamber. The method includes BF 3 , PF 3 , PF 5 , GeF 4 , XeF 2 , CF 4 B 2 F 4 , SiF 4 , Si 2 F 6 , AsF 3 , AsF 5 , XeF 4 , XeF 6 , WF 6 , MoF 6 , C n F 2n+2 , C n F 2n , C n F 2n-2 , C n H x F 2n+2-x , C n H x F 2n-x , C n H x F 2n-2-x(n = 1, 2, 3, …, x = 0, 1, 2, …), COF 2 , SF 6 , SF 4 , SeF 6 , NF 3 , N 2 F 4 , HF, F 2 , or flowing a fluorine-containing gas and a hydrogen-containing gas selected from combinations thereof into the ion source chamber, and generating aluminum ions in the ion source chamber.

[0009] In another aspect, the present invention relates to a method of forming aluminum ions in an ion source chamber. The method includes flowing PF 5 into an ion source chamber containing an aluminum source, and generating aluminum ions in the ion source chamber.

[0010] In another aspect, the present invention relates to an ion source device capable of generating an ion mixture containing aluminum ions. The device includes an ion source chamber having an interior and an internal structure including an aluminum target, and a source of a fluorine-containing gas in fluid communication with the interior, the fluorine-containing gas being BF 3 , PF 3 , PF 5 , GeF 4 , XeF 2 , CF 4 B 2 F 4 , SiF 4 , Si 2 F 6 , AsF 3 , AsF 5 , XeF 4 , XeF 6 , WF 6 , MoF 6 , C n F 2n+2 , C n F 2n , C n F 2n-2 , C n H x F 2n+2-x , C n H x F2n-x , C n H x F 2n-2-x (n = 1, 2, 3…, x = 0, 1, 2…), COF 2 , SF 6 , SF 4 , SeF 6 , NF 3 , N 2 F 4 , HF, F 2 , or a combination thereof, a source of fluorine-containing gas, and a source of hydrogen-containing gas in fluid communication with the interior.

[0011] In yet another aspect, the present invention relates to an ion source device capable of generating an ion mixture containing aluminum ions. The device includes an ion source chamber having an interior and an internal structure including an aluminum target, and a source of PF 5 in fluid communication with the interior.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure relates to an ion implantation method and, in various aspects, to an apparatus, system, device, and method for generating aluminum ions in an ion source chamber and an ion implantation system.

[0014] According to an exemplary method, aluminum ions are generated from an aluminum dopant source by an ion source, and during the generation of the aluminum ions, there is a flow of a fluorine-containing co-gas into the ion source (into the "ion source chamber" or "arc chamber" of the ion source). In some exemplary methods, the aluminum ions are generated using an aluminum dopant source in combination with a flow of both a fluorine-containing co-gas and a hydrogen-containing co-gas into the ion source. In yet other exemplary methods, an inert gas (e.g., N 2 , He, Ar, Kr, Ne, or Xe) can be flowed into the ion source together with a fluorine-containing gas, a hydrogen-containing co-gas, or a combination of a fluorine-containing gas and a hydrogen-containing co-gas.

[0015] The ion source includes a source of aluminum for ionization, which may also be referred to as an "aluminum dopant source" or an "aluminum ion source". The aluminum dopant source may be any aluminum-containing solid material or gaseous material that can be made to be present within the ion source chamber for ionization. The aluminum dopant source may be an aluminum-containing gas that flows into the ion source chamber from an external source. Alternatively, the aluminum dopant source may be a solid aluminum target material that is contained as a solid within the interior of the ion source chamber, such as a sidewall, as part of an exchangeable liner structure or as another solid structure. In some configurations, the solid aluminum target material may be biased to a certain voltage to assist in the sputtering of aluminum from the solid aluminum target.

[0016] Examples of solid aluminum target materials include aluminum oxide, aluminum nitride, aluminum carbide, aluminum boride, and combinations of any two or more thereof. Optionally, the solid aluminum target may contain isotopically enriched aluminum, i.e., the aluminum target may contain one or more aluminum isotopes in an amount greater than the natural abundance of such isotopes.

[0017] During the ionization process, a fluorine-containing gas is flowed into the ion source chamber. The fluorine-containing gas reacts with the aluminum dopant source or causes sputtering of the aluminum dopant source, such as a solid aluminum target, to produce a useful or desirable amount of aluminum source for the ionization of aluminum ions. The fluorine of the fluorine-containing gas is ionized by electrons generated within the ion source chamber. Fluorine or fluorine ions react with the aluminum of the solid aluminum target to release aluminum or aluminum ions into the chamber. The aluminum or aluminum ions are 2Al + Al + 、Al ++ 、Al +++is ionized or further ionized.

[0018] According to an exemplary method of this description, the applicant has identified various fluorine-containing compounds that can be useful or advantageous when used as a fluorine-containing gas for generating aluminum ions from an aluminum dopant source, particularly from a solid aluminum target such as aluminum oxide, aluminum nitride, aluminum carbide, aluminum boride, or a combination of two or more thereof, and optionally in the presence of a hydrogen-containing gas. Exemplary fluorine-containing gases are BF 3 、PF 3 、PF 5 、GeF 4 、XeF 2 、CF 3 、CF 4 、B 2 F 4 、SiF 4 、Si 2 F 6 、AsF 3 、AsF 5 、XeF 4 、XeF 6 、WF 6 、MoF 6 、C n F 2n+2 、C n F 2n 、C n F 2n-2 、C n H x F 2n+2-x 、C n H x F 2n-x 、C n H x F 2n-2-x (n = 1, 2, 3…, x = 0, 1, 2…), COF 2 、SF 6 、SF 4 、SeF 6 、NF 3 、N 2 F 4 、HF、F 2 、or any combination of two or more thereof.

[0019] In a particular method, aluminum ions are generated from an aluminum dopant source, such as a solid aluminum target, in the presence of a fluorine-containing gas within an arc chamber, and the fluorine-containing gas is PF 5 , GeF 4 , and includes them alone or together with a hydrogen-containing gas, or consists of them, or consists essentially of them. The fluorine-containing gas flowing into the arc chamber may include PF 5 , GeF 4 , or a combination thereof, or consists of them, or consists essentially of them, that is, at least 50, 60, 70, 80, 90, 95, 98, 99, or 99.5 percent (by volume) of the total amount of the fluorine-containing gas flowing into the arc chamber is PF 5 , GeF 4 , or a combination thereof. Optionally, the fluorine-containing gas may be flowed in combination with a hydrogen-containing gas.

[0020] Also, according to some exemplary methods, the aluminum ions can be adjusted using an ion source from an aluminum dopant source in the presence of a flow of a combination of a fluorine-containing gas and a hydrogen-containing gas. In an exemplary method, the hydrogen-containing gas may include H 2 , PH 3 , AsH 3 , SiH 4 , B 2 H 6 , CH 4 , NH 3 , GeH 4 , or a combination thereof. Possible advantages of the described methods that include the use of a fluorine-containing gas in combination with a hydrogen-containing gas with an ion source may include improved performance of the ion source in the form of a useful or improved beam current, improved source life, or a useful or advantageous combination or balance of beam current and source life.

[0021] The beam current means the output of a beam of aluminum ions generated and emitted from an ion source. A desirable beam current can be uniform and stable during use and may preferably have a high output (in milliamperes (mA)), but may be selected based on how much the strength of the beam current can affect the source life.

[0022] Various types of ion sources have been developed, including inductively heated cathode ion sources, Freeman-type ion sources, Bernas-type ion sources, and various others. Regardless of the specific type of ion source, the ion source must be able to operate continuously over a long period without being troubled by the need to shut down the ion source due to ion source defects or a decrease in performance level.

[0023] Ion source life (or "source life") means the operating time (e.g., the operating period) of an ion source (e.g., an ion source device used to generate ions for an ion implantation system) that is not accompanied by the ion source being shut down due to ion source defects or a decrease in performance level that requires maintenance, repair, or replacement of the ion source. Shutting down the ion source means reducing or eliminating the power supply to the ion source and ending the generation of aluminum ions as a supply of ions to a different or larger device or equipment such as an ion implantation system. The operating period can be continuous or can be interrupted if the interruption is not due to an ion source defect (including a decrease in performance) but is due to defects or different requirements for shutting down different components of the ion implantation system including the ion source.

[0024] Ion source failures that result in the end of the ion source life, i.e., require the shutdown and termination of the ion source operation, can occur due to any one or more of a variety of causes. These include the accumulation of deposits on the cathode surface in a form that adversely affects the thermionic emission of ions, resulting in a decrease in arc current, performance degradation, and shortening of the ion source life. Another cause can be the harmful corrosion, deposition, and degradation of ion source components caused by ionic substances, such as ionic fluorine species, that flow into the ion source chamber or are generated within the ion source chamber. Yet another cause can be the stripping or sputtering of the cathode material, resulting in a loss of the physical integrity of the cathode and a consequent decrease in ion source performance. Still another cause can be the coating of insulators in the source region, such as the extraction suppression electrode, due to fluoride residues that cause microarcing. Microarcing can reduce the process throughput of the equipment due to the readjustment of the ion source to eliminate the microarcing and can increase the non-uniformity of doping on the substrate, which can adversely affect the device yield. Still another cause can be the accelerated wear of the arc chamber exit aperture due to ionic fluorine species. This can create a wavy exit aperture and can adversely affect the beam uniformity in terms of shape or beam density. Non-uniformity in beam shape or density can reduce the device yield.

[0025] The supply source life or supply source durability can be measured in hours, days, or weeks that the ion source operates as part of a larger system, such as an ion implantation system. The end of the life of the ion source, i.e., the malfunction or performance degradation of the ion source sufficient to require shutting down the ion source, may be confirmed in various ways and may depend on the particular ion source device (e.g., type, model, manufacturer) and the particular larger system (e.g., type, model, manufacturer) in which the ion source, such as an ion implantation system, is used. The end of the supply source life and the need to shut down the ion source can be confirmed as a major supply source malfunction, for example, a malfunction of internal components, or an insulator of the ion source or an insulator of a downstream suppression electrode that will be coated and subject to micro-arching (referred to as "glitching"). Micro-arching causes process errors, resulting in the system operator or system software shutting down the ion source for maintenance (replacement or repair of the ion source).

[0026] According to some preferred methods described, in addition to the presence of a fluorine-containing gas ("cogas"), the presence of a hydrogen-containing gas (also as "cogas") in the ion source chamber can result in a useful or advantageous effect of improving the supply source life of the ion source, and preferably, the method also provides a preferably useful intensity of the beam of aluminum ions. Exemplary methods of this description include using a hydrogen-containing gas as cogas together with a fluorine-containing gas to extend the useful operating life of the ion source, the hydrogen-containing gas being flowed into the ion source as cogas, and the operating life of the ion source being extended compared to the operating life that would be obtained from the operation of a comparable ion source without the flow of the hydrogen-containing gas as cogas to the ion source. The presence of the hydrogen-containing gas as cogas together with the fluorine-containing gas can extend the operating life of the ion source by 10, 25, 50, 100, 200, or 400 percent. The improvement in ion source life can be measured as an increase in the period of use (operating period) of the ion source, i.e., as described herein, an increase in the operating period of the ion source without the need to shut down the ion source due to malfunctions or performance degradation of the ion source, such as "glitching" or any other obstacles or performance degradation that would require maintenance, repair, or replacement of the ion source.

[0027] The amounts of the fluorine-containing gas and optionally the hydrogen-containing gas flowing into the ion source chamber can be selected to result in efficient ionization of the aluminum dopant source and effective generation of an aluminum ion beam, taking into account the supply source life of the ion source. Useful or preferred relative amounts of the hydrogen-containing gas and the fluorine-containing gas can be selected to provide one or more of the desired effects of a useful beam current, a useful supply source life, or a balance of a desired beam current and a desired supply source life. The range of relative amounts of the hydrogen-containing gas and the fluorine-containing gas can have a balanced effect, including a relatively higher beam intensity with a decrease in supply source life obtained from a relatively lower relative amount of the hydrogen-containing gas compared to a useful or increased supply source life and a relatively lower beam intensity obtained from a relatively higher relative amount of the hydrogen-containing gas.

[0028] In an exemplary method, the useful relative amount range of the hydrogen-containing gas to the fluorine-containing gas can be within a range of 2 to 60 percent (by volume) of the hydrogen-containing gas per total amount of the hydrogen-containing gas and the fluorine-containing gas. Within this range, the specific relative amount of the hydrogen-containing gas per total of the hydrogen-containing gas and the fluorine-containing gas can be selected based on desired performance such as the desired ion beam intensity relative to the source life. In some examples, a lower relative amount of the hydrogen-containing gas to the fluorine-containing gas produces a beam current located at the upper limit or upper portion of the range. See FIGS. 6, 9, and 14. However, using a lower relative amount of the hydrogen-containing gas may result in a shorter source life than the source life obtained using a higher relative amount of the hydrogen-containing gas, i.e., as the relative amount of the hydrogen-containing gas increases, the source life is improved. For a combination of a longer source life and a lower (but acceptable) beam intensity, the amount of the hydrogen-containing gas can be within a range of 5 to 60 percent (by volume) hydrogen-containing gas per total amount of the hydrogen-containing gas and the fluorine-containing gas, for example, within a range of 10 to 50 percent (by volume) hydrogen-containing gas per total amount of the hydrogen-containing gas and the fluorine-containing gas.

[0029] The amount of the hydrogen-containing gas per total amount of the hydrogen-containing gas and the fluorine-containing gas has also been shown to affect the amount of undesirable non-aluminum ions generated within the arc chamber during ion generation. In particular, in an arc chamber containing tungsten on its inner surface, a higher relative amount of the hydrogen-containing gas per total amount of the hydrogen-containing gas and the fluorine-containing gas results in, during the generation of the desired aluminum ions, a lower amount of tungsten ions (W + ), tungsten fluoride ions (WF x + ), or both being desirably generated. See FIGS. 7, 8, 10, 11, 13, 15, 16, 18, and 19. Experimental data shows that a higher relative amount of the hydrogen-containing gas results in a lower amount of tungsten ions (W + ) or tungsten fluoride ions (WF x +) a useful or advantageous effect of reduction can be brought about, that is, during the operation of the ion source, a relatively small amount of tungsten ions (W + ) or tungsten fluoride ions (WF x + )(x = 1, 2, 3, 4, 5 or 6) or both will be generated. Reducing the amount of these non-aluminum ions during the ionization process can also affect (e.g., increase) the source life of the ion source.

[0030] The use of a hydrogen-containing gas as co-gas in the described manner has various effects on the method of generating aluminum ions using the ion source, based on the design of the ion source. The effects of the hydrogen-containing gas on beam current, the makeup of the beam spectrum, source life, etc. can vary depending on some of the characteristics of the design and operation of the ion source, such as the structure of the arc chamber, the position of the solid aluminum target, the composition of the solid aluminum target (AlN or Al 2 O 3 ), the shape and form of the aluminum target, the arc voltage, the presence and strength of the source magnet, and the position and chemical makeup of the cathode and the counter cathode. Various suppliers (manufacturers) of ion source devices have various designs regarding the above other ion source characteristics. Therefore, the effects of the presence and amount of the hydrogen-containing gas as co-flow gas among the methods of generating aluminum ions can vary based on the design (structure, makeup) of the ion source device and the operating parameters (e.g., arc voltage, strength of the source magnet).

[0031] As shown by the following examples, the presence of a hydrogen-containing co-gas added to the ion source and the fluorine-containing gas can result in various performance characteristics in terms of beam current (total beam intensity), beam spectrum (e.g., content of tungsten and other types of ions), and tungsten beam current (intensity of current related to tungsten ions) when generating aluminum ions. For each of these various performance characteristics, a desired optimal or maximum performance level can be determined in relation to the range of hydrogen-containing gas used. The position of the maximum performance level can depend on factors including the design of the ion source device, operating parameters, etc., as described. Thus, the method of the present invention can include flowing hydrogen gas into the ion source in an amount that provides a desired maximum or optimal performance with respect to peak beam current (total beam intensity), desired beam spectrum (e.g., low tungsten ion content), and tungsten beam current (beam intensity of the tungsten component), each of which is related to the range of hydrogen-containing gas. The method can function at a level of hydrogen-containing gas selected to identify any one of these respective performances and provide the best performance for a single factor, or can function at a level of hydrogen-containing gas selected to have a balanced effect on two or three of these factors.

[0032] As an example, the method can include flowing hydrogen-containing gas into the ion source in an amount at or near the level that generates the (total) peak beam current. The (total) beam current varies in relation to the amount of hydrogen-containing gas flowing into the ion source. The beam current exhibits a maximum current ("maximum beam current") at a position along the range. The maximum beam current can be at an amount (concentration, percentage) of hydrogen-containing gas that is zero, or at an amount (concentration, percentage) of hydrogen-containing gas that is greater than zero.

[0033] The described method may include flowing a hydrogen-containing gas into the ion source in an amount within the 2, 5, 10, 20, 30, 40, 50, or 60 percent points of the maximum beam current. If the maximum beam current is produced at 20 percent hydrogen, the method may flow the hydrogen-containing gas in an amount from 18 to 22 percent (which is within 2 percent points of 20 percent), or in an amount from 15 to 25 percent (which is within 5 percent points of 20 percent), or in an amount from 10 to 30 percent (which is within 10 percent points of 20 percent). If the maximum beam current is at or near the amount of 0 percent hydrogen-containing gas, an exemplary method of the invention may include flowing the hydrogen-containing gas into the ion source in an amount less than 10, 5, or 2 percent.

[0034] The magnitude of the range of useful amounts of hydrogen-containing gas (useful levels of flow as a percentage) for a particular ion source and method can vary based on the nature of the response of the beam current to the inflow of hydrogen-containing gas into the ion source. For a system that exhibits a relatively stable beam current level over a range of inflows of hydrogen-containing gas (see FIG. 21), the range of useful amounts of hydrogen-containing gas can be broader and can extend over a greater percentage point range from the peak or maximum value.

[0035] Other examples of this description may include flowing a hydrogen-containing gas into the ion source in an amount that achieves a desirable balance of high (total) beam intensity and a low amount of tungsten ions in the beam. The amount of tungsten ions in the ion beam produced according to this method varies in relation to the amount of hydrogen-containing gas flowed into the ion source and generally decreases as the amount of hydrogen-containing gas increases.

[0036] The described method involves tungsten ions (W in the ion beam +may include flowing a hydrogen-containing gas to the ion source in an amount that achieves a desired reduction. The hydrogen-containing gas, when compared to the amount of tungsten ions in an ion beam produced in a manner comparable but using a hydrogen-containing gas at a concentration of zero percent, results in a decrease in the amount of tungsten ions (W + ) in the ion beam of at least 5, 10, 20, 40, 50, or 60 percent. An example of the method described involves flowing a hydrogen-containing gas to the ion source in an amount that reduces the amount of tungsten ions (W + ) in the ion beam by at least 5, 10, 20, 40, 50, or 80 percent compared to the amount of tungsten ions that would be present in an ion beam produced using a hydrogen-containing gas at a concentration of zero percent flowing into the ion source. Exemplary amounts of the hydrogen-containing gas that may result in a reduction of tungsten ions (W + ) in the ion beam of at least one of these amounts may be at least 5, 10, 15, 20, 30, 40, 50, or 60 percent hydrogen-containing gas.

[0037] Regarding the reduction of tungsten ions in the ion beam, there may be a reduction in beam glitching, for example, measured in glitches per hour during operation of the ion source. A single "glitch" is an abrupt, undesirable decrease in beam quality during ion generation at the ion source and can be caused by undesirable arcing inside the arc chamber or at the suppression electrode. The method described may include flowing a hydrogen-containing gas to the ion source in an amount that achieves a desired reduction in glitching of the ion source during the process of generating aluminum ions compared to the amount of glitching in a comparable process where no hydrogen-containing gas is flowed to the ion source.

[0038] The hydrogen-containing gas can reduce ion source glitching by at least 20, 50, 70, or 80 percent when compared to glitching that would occur when operating the ion source in a comparable manner but with the hydrogen-containing gas not flowing into the ion source. This reduction is the result of a mixture or parallel flow of the hydrogen-containing gas. An example of the method described can include flowing the hydrogen-containing gas into the ion source in an amount that reduces the amount of ion source glitching by at least 20, 50, 70, or 80 percent compared to the amount of glitching that would occur in the ion source with no flow of the hydrogen-containing gas. Exemplary amounts of the hydrogen-containing gas that can result in a desirable reduction of ion source glitching can be at least 5, 10, 15, 20, 30, 40, 50, or 60 percent hydrogen-containing gas.

[0039] Referring now to the figures, FIG. 1 is a diagram of an ion source 10 as a component of an ion implantation system. A gas supply line 14 is configured to supply one or more co-gases to the ion source 10 for use during an ionization process that takes place inside the ion source, i.e., within an ion source chamber (or “arc chamber”) 12 of the ion source 10. Thus, the ion source 10 provides an ion source chamber 12 that houses an aluminum dopant source, such as a solid aluminum target, that is likely to react with a fluorine-containing gas or a derivative thereof to cause the release of aluminum ions into the arc chamber.

[0040] Figure 2A is a cross-sectional view of the ion source 10 showing the generation of plasma 16 inside the ion source 10 (ion source chamber 12). One or more types of co-gas (e.g., a fluorine-containing gas, a hydrogen-containing gas, or both) are flowed through the co-gas supply line 14 in the direction indicated by arrow A. The ion source 10 houses inside thereof an aluminum dopant source such as a solid aluminum target that easily reacts with the fluorine-containing gas for the emission of aluminum ions into the ion source chamber. Exemplary aluminum dopant sources can be an exchangeable sidewall liner, a counter cathode, or a solid aluminum target in the form of an extension or "fin" disposed at an internal position within the ion source chamber.

[0041] As part of the ion source 10, other components suitable for the operation of the ion source 10 and the ion source chamber 12 are also included. Among the several possible functional components, they include sidewalls (including the bottom, top, opposing side faces, and opposing ends), a cathode, a counter cathode, a voltage source between the cathode and the counter cathode, and a magnet for causing the movement of electrons inside the arc chamber. The sidewalls or removable liners can be made of tungsten, molybdenum, graphite among several materials. The cathode and the counter cathode may be made of any useful material, typically each made of tungsten. The ion source chamber is designed to limit the gas (ion beam) from leaving the inside other than through the outlet opening.

[0042] Specific examples of solid aluminum targets in the form of three-dimensional extensions or “fins” that extend within the internal space of the ion source chamber are shown in FIGS. 2B, 2C, and 2D. FIGS. 2B, 2C, and 2D show the ion source chamber 12 that defines the interior. The inner surface of the ion source chamber 12 includes a top, a bottom, and side walls, as well as ends, and these can be made of known materials such as tungsten, molybdenum, or aluminum target material. FIGS. 2B and 2C are cross-sectional views of an exemplary ion source chamber 12 as seen from the position of the cathode at one end of the ion source, looking into the ion source chamber in the direction of the counter cathode at the opposite end. An ion beam containing a mixture of ions generated within the ion source chamber 18 exits through the top of the ion source chamber 18.

[0043] FIG. 2B shows an internal surface 20 in the form of an exemplary removable liner that can be removed and replaced, for example, during maintenance of the ion source chamber 12. In FIG. 2B, the removable liner that defines the bottom inner surface also includes an elongate aluminum target structure 22 that extends into the space defined as the ion source chamber 18. The elongate aluminum target structure 22 has a three-dimensional form including length, width, and height, and shows an aspect ratio of height (the dimension extending away from the inner surface of the ion source chamber 18) to width of at least 1:1, preferably at least 2:1, 5:1, 10:1, or at least 20:1. The height and width of the elongate aluminum target structure 22 are shown in the cross-sectional views of FIGS. 2B and 2C, and the structure 22 also has a length (not shown) that extends along the length of the ion source chamber 18 between the cathode and the counter cathode.

[0044] An alternative example of the elongate aluminum target structure 22, which may optionally be included as part of the removable liner, is shown in FIG. 2C. Compared to the single structure at the bottom of the ion source chamber 12 in FIG. 2B, there are two elongate aluminum target structures 22 in FIG. 2C, one on each side of the ion source chamber 12. The two elongate aluminum target structures 22 in FIG. 2C extend from the opposing sidewalls of the ion source chamber 12 and are oriented at an angle non-perpendicular to the surface of the sidewalls, as compared to extending from the bottom of the ion source chamber 12 in FIG. 2B.

[0045] FIG. 2D is a top view of the interior of another ion source chamber 200 including arc chamber walls 202a, 202b, 202c, and 202d. Inside the chamber, there is a cathode 204 at one end and an anode 206 at the other end. The arc chamber walls are covered on the sidewalls by arc chamber liners 210, 212, 214, and 216, and on the bottom side by arc chamber liners 218, 220, and 222. There is also a gas injection opening 208 on the bottom wall. In embodiments, one, two, three, four, five, or six of the arc chamber liners 210, 212, 214, 216, 218, 220, and / or 222 may be made of an aluminum-containing (aluminum target) material. In embodiments, the arc chamber liner 218 or 220 may be made of an aluminum-containing (aluminum target) material.

[0046] A solid aluminum target including an elongate structure extending into the space of the ion source chamber 18 positions the solid aluminum target directly within the magnetic field of the ion source chamber. The magnetic field of the ion source chamber is adapted to confine electrons emitted from the cathode toward the space at the center or middle portion of the chamber. An anode or reflecting electrode pushes back the electrons that have passed through the magnetic field. The magnetic field also provides the spin of the electrons emitted from the cathode to enhance the likelihood of collision with atoms or molecules of the gas contained within the chamber. A solid aluminum target extending from the inner surface (bottom or sidewall) of the ion source chamber to a portion of the solid aluminum target at a more interior location (e.g., the central portion) of the ion source chamber positions the target at a location of a stronger portion of the magnetic field. This positioning positions a portion of the solid aluminum target in more direct contact with the plasma of the ion source.

[0047] FIG. 3 is a diagram of an ion implantation process system 300 that includes an ion source 316 and at least one (optionally two or more) storage and dispensing containers 302 that hold a co-gas or combination of co-gases as described. An exemplary co-gas is a fluorine-containing gas that is supplied to the ion source 316 to generate aluminum ions for ion implantation doping of a substrate 328 in an ion implantation chamber 301 shown to react in situ with a fixed aluminum target disposed within the ion source 316. Although only a single dispensing container 302 is shown, the system 300 can include two or more such containers to supply two or more different co-gases or co-gas mixtures to the ion source 316.

[0048] The storage and dispensing container 302 comprises a container wall surrounding an internal volume that holds the cogas or a mixture of cogases. The container 302 may be a conventional gas cylinder having an internal volume adapted to hold only gas, or the container may contain an absorbent material having an adsorption affinity for the reactive gas, and the cogas is desorbable from the absorbent material for discharge from the container under dispensing conditions. The storage and dispensing container 302 includes a valve head 308 that is in gas flow communication and connected to a discharge line 312. A pressure sensor 310 is disposed within the line 312 together with a mass flow controller 314. Other monitoring and sensing components may be connected to the line and to control means such as an actuator, a feedback and computer control system, a cycle timer, and the like.

[0049] One type of coflow gas or a combination of coflow gases (a hydrogen-containing gas, a fluorine-containing gas, or both) can flow from the container 302 through a conduit and through associated controllers (not shown) such as, for example, a pressure controller, a temperature controller, a mass flow controller, etc. The plurality of containers 302 can be any useful storage containers used to individually handle and separately store cogases such as hydrogen-containing gases, fluorine-containing gases, etc. For example, the system 300 may include two separate containers 302, namely, one container that holds a high-purity fluorine-containing gas as described and a second container 302 that holds a high-purity hydrogen-containing gas as described. For example, there may be additional additional containers 302 for supplying an inert gas. According to other exemplary systems and containers, the container 302 can hold a mixture of a fluorine-containing gas and a hydrogen-containing gas in a single container. The two types of gases can be any of those described herein, and the two different gases can be contained in the container (without including other gases) in any of the relative amounts described herein.

[0050] Container 302 may be any storage container useful for supplying one or more types of fluorine-containing gases or hydrogen-containing gases to system 300. Examples thereof include non-absorbent type pressurized storage containers and absorbent-based storage containers capable of storing co-gas at superatmospheric or subatmospheric pressure for delivery at superatmospheric or subatmospheric pressure. Examples of absorbent-based gases and non-absorbent-based storage and supply containers include those commercially available from Entegris, Inc. (Billerica, Massachusetts, USA). Specific examples of absorbent-based products are marketed under the trademark of SDS. Examples of pressure regulating containers including an internal gas regulator (alternatively, the pressure regulator may be incorporated into the valve) are commercially available from Entegris, Inc. (Billerica, Massachusetts, USA) under the trademark of VAC. Absorbent-based containers may include any useful type of solid adsorbent material, such as metal organic framework (MOF) adsorbents like zeolite inorganic framework (ZIF), carbon-based adsorbents, etc.

[0051] Ion implantation chamber 301 houses ion source 316 for receiving one or more types of co-gas dispensed from line 312. The fluorine-containing gas can react with the solid aluminum target within the ion source chamber to generate aluminum ions, and these aluminum ions form ion beam 305 containing aluminum ions. Ion beam 305 exits the ion source through the ion source exit aperture and passes through the extraction suppression electrode. Ion beam 305 passes through mass analyzer unit 322, which selects the desired ions for implantation, i.e., aluminum ions, and rejects the non-selected ions.

[0052] The selected ions pass through acceleration electrode array 324 and then through deflection electrode 326. The resulting focused ion beam is made to impinge on substrate element 328 disposed on rotatable holder 330 mounted on spindle 332 to form a doped (aluminum-doped) substrate as an ion implantation product.

[0053] The various sections of the ion implantation chamber 301 are evacuated by pumps 320, 342, and 346, respectively, through lines 318, 340, and 344.

[0054] According to some exemplary methods of the present invention, a solid aluminum ion precursor, i.e., a solid aluminum target containing aluminum nitride (AlN) or a solid aluminum target containing alumina (Al 2 O 3 ) can be used to generate aluminum ions in an ion source chamber (or "arc chamber") of an ion source in combination with a fluorine-containing gas, a hydrogen-containing gas, or both. The solid aluminum target may be in the form of an exchangeable liner or other solid structure to be housed within the ion source chamber. The generated aluminum ion beam exhibits a useful or advantageous intensity while also exhibiting a useful or relatively long source life, and the aluminum ion beam persists over a useful period.

[0055] The following examples show that various fluorine-containing gases can be useful for generating a beam of aluminum ions using an ion source according to the methods and apparatus described herein, and that various combinations of fluorine-containing gases and hydrogen-containing gases can also be useful.

Example

[0056] Example 1 (FIG. 4) Aluminum nitride precursor with various fluorine-containing co-gases but without hydrogen-containing co-gases.

[0057] FIG. 4 shows experimental examples of the Al + beam current obtained by using solid aluminum nitride as a solid aluminum target with different (single) fluorine-containing co-gases and no hydrogen-containing co-gases. The results show that various different fluorine-containing gases can be used to generate a useful aluminum ion beam from an ion source.

[0058] The data in Figure 4 shows that for PF 3 , PF 5 , GeF 4 , BF 3 , and XeF 2 , each is effective as a co-gas in the ion source for generating aluminum ions using aluminum nitride as a solid aluminum target over various flow rates of the co-gas. As a specific observation result, PF 5 is effective as a co-gas and provides a beam current strength superior to other fluorine-containing gases over various gas flow rates.

[0059] Example 2 (Figure 5) Aluminum oxide precursors with various fluorine-containing co-gases but without hydrogen-containing co-gases.

[0060] Figure 5 shows experimental examples of the Al + beam current obtained by using solid aluminum oxide as a solid aluminum target with different (single) fluorine-containing co-gases and without any hydrogen-containing co-gases. The results show that various different fluorine-containing gases can be used (alone) to generate a useful aluminum ion beam from the ion source.

[0061] The data in Figure 5 shows that for PF 3 , PF 5 , GeF 4 , BF 3 , and XeF 2 , each is effective as a co-gas in the ion source for generating aluminum ions using aluminum nitride as a solid aluminum target over various flow rates of the co-gas. The various fluorine-containing gases have various performance levels and generate beam currents of various strengths. As a specific observation result, PF 5 provides a beam current strength superior to other fluorine-containing gases over various gas flow rates.

[0062] Example 3 (Figs. 6, 7, and 8) PF 5 Aluminum nitride precursors with fluorine-containing coke oven gas and various amounts of hydrogen-containing coke oven gas (H 2 ).

[0063] FIG. 6 shows solid aluminum nitride as a solid aluminum target, PF 5 fluorine-containing coke oven gas, and various amounts of hydrogen (H 2 ) as hydrogen-containing coke oven gas, and an experimental example of the Al + beam current obtained by using them. The data was generated by a process in which PF was flowed at 1 standard cubic centimeter per minute (sccm) while varying the flow rate of hydrogen. The arc voltage (ArcV) was 75 volts and the output of the source beam was 20 milliamperes (mA). 5

[0064] The results in FIG. 6 show that the beam current changes over various relative amounts of hydrogen-containing gas relative to the total of hydrogen-containing gas and fluorine-containing gas. The less the amount of hydrogen, the relatively larger beam current is provided. However, by using a larger amount of hydrogen, as a result, the level of certain non-aluminum ions will decrease (see FIGS. 7 and 8), whereby the source life can be extended. The maximum beam current occurs at approximately 5 percent hydrogen. To maximize the total beam current strength, the method of the present invention can be performed by flowing hydrogen to the ion source in an amount of about 5 percent. Alternatively, to obtain a balanced and desirably high beam current strength by a relatively longer ion source life or a relatively smaller amount of tungsten ions in the ion beam, the method can be performed by flowing different (more) amounts of hydrogen in the range of, for example, 2 to 60 percent, or 3 to 40 or 45 percent, or 1 to 15 or 25 percent, to the ion source.

[0065] The maximum beam current occurs at a hydrogen concentration of approximately 5 percent, but the maximum beam current can be larger or smaller for various ion source designs and various operating parameters (e.g., arc voltage) with other factors being similar. A useful method for different ion sources or different operating parameters is to adjust the amount of hydrogen-containing gas based on the amount of hydrogen-containing gas that has been found to result in the maximum beam current.

[0066] Figure 7 shows the beam current versus atomic mass unit (AMU) for aluminum ions and non-aluminum ions generated in Example 3.

[0067] The results in Figure 7 show that as the relative amount of hydrogen-containing co-gas increases, the specific beam current of non-aluminum ion species decreases. Specifically, the beam has a significantly reduced amount of W ++ ions, W + ions, and WF x + ions, which are ions that can adversely affect the performance and source life of the ion source, for example, by causing "glitching" deposition or eroding the arc chamber exit aperture.

[0068] Figure 8 shows the beam current of tungsten ions (W + ) versus various amounts of hydrogen (percentage), and shows that as the level of hydrogen increases, the level of tungsten ions in the resulting ion beam gradually decreases.

[0069] For the system and method of Example 3, the preferred range of hydrogen is the amount of tungsten ions (W +) may be in a range that causes a desirable decrease, which can be an amount of hydrogen of at least 5, 10, 20, 30, 40, 50, or 60 percent as shown in FIGS. 7 and 8. Optionally, the specific amount of hydrogen used can be balanced with the desirable (e.g., optimized) beam current intensity as shown in FIG. 6. An exemplary way to balance a desirably large total beam current (FIG. 6) with a desirably small tungsten ion beam current (FIGS. 7, 8) is to flow hydrogen (or another hydrogen-containing gas) in an amount in the range from 2 to 60 percent, or in the range from 5 or 10 percent to 20, 25, 30, 35, 40, 45, 50, or 55 percent.

[0070] Within these ranges, the system can function while suppressing the level of beam instability or glitching caused by the useful level of hydrogen gas. According to the method of the present invention, the amount of hydrogen used can be selected to result in a reduction in the level of glitching, for example, at least 5, 10, 20, 50, 70, or 80 percent reduction in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0071] Example 4 (FIGS. 9, 10, and 11) PF 5 Aluminum oxide precursors with fluorine-containing co-gas and various amounts of hydrogen-containing co-gas (H 2 ).

[0072] FIG. 9 shows an experimental example of the Al 2 beam current obtained by using solid aluminum oxide as a solid aluminum target, PF5 fluorine-containing co-gas, and various amounts of hydrogen-containing co-gas (H + ). The data was generated by a process of flowing 1.2 standard cubic centimeters per minute (sccm) of PF 5 while varying the flow rate of hydrogen. The arc voltage (ArcV) was 75 volts and the output of the source beam was 20 milliamperes (mA).

[0073] The results in FIG. 9 show that the beam current varies over various relative amounts of the hydrogen-containing gas relative to the total of the hydrogen-containing gas and the fluorine-containing gas. The less the amount of hydrogen, the relatively greater beam current is provided, although the beam current is relatively consistent for the use of the hydrogen-containing gas in the range of hydrogen up to about 30 or 35 percent. Also, the greater amount of hydrogen will result in a reduction in the level of certain non-aluminum ions (see FIGS. 10 and 11), whereby the source life can be extended.

[0074] The maximum beam current occurs at approximately 10 percent hydrogen. To maximize the overall beam current strength, the method of the present invention can be carried out by flowing hydrogen to the ion source in an amount of about 10 percent. Alternatively, to obtain a balanced and desirably high beam current strength with a relatively longer ion source life or a relatively lesser amount of tungsten ions in the ion beam, the method can be carried out by flowing different (greater) amounts of hydrogen to the ion source in an amount within the range of, for example, 3 to 60 percent, or 5 to 35, 40, 45, 50, 55, or 60 percent, or from 5 or 10 percent to 25 or 30 percent.

[0075] The maximum beam current occurs at approximately 10 percent hydrogen, although the maximum beam current can be greater or less for various ion source designs and various operating parameters (e.g., arc voltage). A useful method for different ion sources or operating parameters can be to adjust the amount of the hydrogen-containing gas based on the amount of the hydrogen-containing gas that has been found to result in the maximum beam current.

[0076] FIG. 10 shows the beam current versus atomic mass unit (AMU) for aluminum ions and non-aluminum ions generated according to Example 4.

[0077] The results in Figure 10 show that the use of hydrogen-containing coke oven gas reduces the specific beam current of non-aluminum ion species. For example, the beam is significantly reduced in the amount of W by a flow of 20 percent hydrogen gas. + It contains.

[0078] Figure 11 shows the beam current of tungsten ions (W + ) for various amounts of hydrogen (percentage), and shows that the level of tungsten ions in the resulting ion beam gradually decreases as the level of hydrogen increases.

[0079] For the system and method of Example 4, the preferred range of hydrogen may be a range that results in a desired reduction of tungsten ions (W + ) in the ion beam, which may be at least 5, 10, 20, 30, 40, 50, or 60 percent hydrogen as shown in Figures 10 and 11. Optionally, the specific amount of hydrogen used may be balanced with the desired (e.g., optimized) beam current intensity as shown in Figure 9. An exemplary method for balancing a preferably large total beam current (Figure 9) with a preferably small tungsten ion beam current (Figures 10, 11) may be to flow hydrogen (or another hydrogen-containing gas) in an amount within the range of 2 to 60 percent, or from 5 or 10 percent to 20, 25, 30, 35, 40, 45, 50, or 55 percent.

[0080] Within these ranges, the system can function while suppressing the level of glitching caused by useful levels of hydrogen gas. According to the method of the present invention, the amount of hydrogen used can be selected to result in a reduction in the level of glitching, for example, at least 20, 50, 70, or 80 percent reduction in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0081] Example 5 (Figure 12) GeF 4Aluminum nitride precursors with fluorine-containing coal gas and various amounts of hydrogen-containing coal gas (H 2 ).

[0082] FIG. 12 shows solid aluminum nitride as a solid aluminum target, GeF 4 fluorine-containing coal gas, and various amounts of hydrogen-containing coal gas (H 2 ), and an experimental example of the Al + beam current obtained by using it. The data was generated by a process in which GeF 4 at 0.5 standard cubic centimeters per minute (sccm) was flowed while varying the flow rate of hydrogen. The arc voltage (ArcV) was 75 volts, and the output of the source beam was 20 milliamperes (mA).

[0083] The experiment also showed that this beam current varied over various relative amounts of hydrogen-containing gas relative to the total of hydrogen-containing gas and fluorine-containing gas. The less the amount of hydrogen, the relatively larger beam current is provided. However, by using a larger amount of hydrogen, the level of certain non-aluminum ions will be substantially reduced as a result (see FIG. 12), thereby extending the source life.

[0084] The maximum beam current occurs when there is no flow of hydrogen. To obtain a desirably high beam current intensity with a balanced balance by a relatively longer ion source life or a relatively smaller amount of tungsten ions in the ion beam, the method can be performed by flowing an amount of hydrogen greater than zero into the ion source.

[0085] The maximum beam current occurs at zero percent hydrogen, but the maximum beam current can occur at a greater (non-zero) amount of hydrogen for different ion source designs and different operating parameters (e.g., arc voltage). A useful method for different ion sources or operating parameters can adjust the amount of hydrogen-containing gas based on the amount of hydrogen-containing gas that has been found to result in the maximum beam current.

[0086] Figure 12 shows the beam current versus atomic mass unit (AMU) of aluminum ions and non-aluminum ions generated in Example 5.

[0087] The results in Figure 12 show that the use of hydrogen-containing co-gas reduces the specific beam current of non-aluminum ion species. Specifically, the beam contains a significantly reduced amount of W + ions and WF x + ions, which can negatively affect the performance and source life of the ion source, for example, by causing "glitching" or eroding the arc chamber exit aperture.

[0088] The system of Example 5 can function while suppressing the level of glitching brought about by useful levels of hydrogen gas. According to the method of the present invention, the amount of hydrogen used can be selected to result in a reduction in the level of glitching, for example, at least 20, 50, 70, or 80 percent reduction in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0089] Example 6 (Figure 13) Aluminum oxide precursor with fluorine-containing co-gas and various amounts of hydrogen-containing co-gas (H 4 ) 2 )

[0090] Figure 13 shows an experimental example of the Al 4 beam current obtained by using solid aluminum oxide as a solid aluminum target, fluorine-containing co-gas, and various amounts of hydrogen-containing co-gas (H 2 ). The data was generated by a process of flowing 0.4 standard cubic centimeters per minute (sccm) of GeF + while varying the flow rate of hydrogen. The arc voltage (ArcV) was 60 volts, and the output of the source beam was 20 milliamperes (mA). 4

[0091] The experiments also showed that the beam current varied over a range of different relative amounts of the hydrogen-containing gas with respect to the total of the hydrogen-containing gas and the fluorine-containing gas. The less the amount of hydrogen, the relatively greater beam current is provided. Also, by using a greater amount of hydrogen, as a result, the level of certain non-aluminum ions is substantially reduced (see Figure 13), whereby the source life can be extended.

[0092] The maximum beam current occurs with no flow of hydrogen. To obtain a desirably high beam current strength that is balanced by a relatively longer ion source life or a relatively lower amount of tungsten ions in the ion beam, the method can be performed by flowing an amount of hydrogen greater than zero to the ion source.

[0093] The maximum beam current occurs at zero percent hydrogen, but the maximum beam current can occur at a greater (non-zero) amount of hydrogen for different ion source designs and different operating parameters (e.g., arc voltage). A useful method for different ion sources or operating parameters can be to adjust the amount of the hydrogen-containing gas based on the amount of the hydrogen-containing gas that has been found to result in the maximum beam current.

[0094] Figure 13 shows the beam current versus atomic mass unit (AMU) of aluminum ions and non-aluminum ions generated in Example 6.

[0095] The results in Figure 13 show that the use of the hydrogen-containing co-gas reduces the specific beam current of non-aluminum ion species. Specifically, the beam contains a significantly reduced amount of W + ions and WF x + ions, which are ions that can adversely affect the performance and source life of the ion source, for example, by causing "glitching" or eroding the arc chamber exit aperture.

[0096] The system of Example 6 can function while suppressing the level of glitching caused by useful levels of hydrogen gas. According to the method of the present invention, the amount of hydrogen used can be selected to result in a reduction in the level of glitching, such as at least a 20, 50, 70, or 80 percent reduction in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0097] Example 7 (Figures 14, 15, and 16) PF 3 Aluminum oxide precursor containing fluorine-containing cogas and various amounts of hydrogen-containing cogas (H 2 ).

[0098] Figure 14 shows an experimental example of the Al 3 beam current obtained by using solid aluminum oxide as a solid aluminum target, PF 2 fluorine-containing cogas, and various amounts of hydrogen-containing cogas (H + ). The data was generated by a process of flowing 0.75 standard cubic centimeters per minute (sccm) of PF 3 while varying the flow rate of hydrogen. The arc voltage (ArcV) was 75 volts and the output of the source beam was 20 milliamperes (mA).

[0099] The results in Figure 14 show that the beam current changes over various relative amounts of hydrogen-containing gas relative to the total of the hydrogen-containing gas and the fluorine-containing gas. The less the amount of hydrogen, the relatively larger beam current is provided. However, by using a larger amount of hydrogen, as a result, the level of certain non-aluminum ions is substantially reduced (see Figures 15 and 16), whereby the source life can be extended.

[0100] The maximum beam current occurs in the absence of a hydrogen flow. To obtain a balanced and desirably high beam current strength, relative to a relatively long ion source lifetime or a relatively low amount of tungsten ions in the ion beam, the method can be performed by flowing an amount of hydrogen within the range of more than zero, for example, from 1, 2, or 3 to 45, 50, 55, or 60 percent, or up to 35, 40, or 45 percent, or from 10 percent to 25, 30, 35, or 40 percent, into the ion source.

[0101] The maximum beam current occurs at zero percent hydrogen, but the maximum beam current can occur at a greater (non-zero) amount of hydrogen for different ion source designs and different operating parameters (e.g., arc voltage). A useful method for different ion sources or operating parameters can be to adjust the amount of hydrogen-containing gas based on the amount of hydrogen-containing gas that has been found to result in the maximum beam current.

[0102] Figure 15 shows the beam current versus atomic mass unit (AMU) for aluminum ions and non-aluminum ions generated in Example 7.

[0103] The results in Figure 15 show that the use of hydrogen-containing co-gas reduces the specific beam current of non-aluminum ion species. Specifically, the beam contains a significantly reduced amount of W ++ ions, W + ions, and WF x + ions, which are ions that can negatively affect the performance and source lifetime of the ion source, for example, by causing "glitching" or eroding the arc chamber exit aperture.

[0104] Figure 16 shows the beam current of tungsten ions (W + ) versus various amounts of hydrogen (percentage), and shows that the level of tungsten ions in the resulting ion beam decreases as the level of hydrogen increases.

[0105] For the system and method of Example 7, the preferred hydrogen range may be a range that results in a desirable decrease in tungsten ions (W + ) in the ion beam, which may be an amount of hydrogen of at least 3, 5, 10, 20, 30, 40, 50, or 60 percent as shown in FIGS. 19 and 20. The specific amount of hydrogen used may be balanced with the desired beam current strength as shown in FIG. 18. An exemplary method for balancing a preferably large total beam current (FIG. 14) and a preferably small tungsten ion beam current (FIGS. 15, 16) may be to flow hydrogen (or another hydrogen-containing gas) in an amount within the range of 2 to 60 percent, or from 3 or 5 percent to 20, 25, 30, 35, 40, 45, 50, or 55 percent.

[0106] Within these ranges, the system may function while suppressing the level of glitching caused by a useful level of hydrogen gas. According to the method of the present invention, the amount of hydrogen used may be selected to result in a decrease in the level of glitching, for example, at least 20, 50, 70, or 80 percent decrease in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0107] Example 8 (FIGS. 17, 18, and 19) BF 3 Aluminum oxide precursors with fluorine-containing co-gas and various amounts of hydrogen-containing co-gas (H 2 ).

[0108] FIG. 17 shows an experimental example of the Al 3 beam current obtained by using solid aluminum oxide as a solid aluminum target, BF 2 fluorine-containing co-gas, and various amounts of hydrogen-containing co-gas (H + ). The data shows the BF at 1 standard cubic centimeter per minute (sccm) while varying the flow rate of hydrogen 3It was generated by a process of flowing. The arc voltage (ArcV) was 75 volts and the output of the source beam was 20 milliamperes (mA).

[0109] The results in FIG. 17 show that the beam current is relatively stable over various relative amounts of hydrogen-containing gas with respect to the total of hydrogen-containing gas and fluorine-containing gas. The maximum beam current occurs at approximately 25 percent hydrogen. To maximize the total beam current strength, the method of the present invention can be carried out by flowing hydrogen to the ion source in an amount of about 25 percent. Alternatively, to obtain a balanced and desirably high beam current strength by a relatively longer ion source life or a relatively small amount of tungsten ions in the ion beam, the method can be carried out by flowing different (more) amounts of hydrogen to the ion source in an amount within the range of, for example, 5 to 40 percent, or 20 to 30 percent, or 25 to 35 percent. However, due to the consistent range of beam current with respect to hydrogen gas, any hydrogen level between zero and 60 percent can be useful.

[0110] FIG. 18 shows the beam current versus atomic mass unit (AMU) of aluminum ions and non-aluminum ions generated according to Example 8.

[0111] The results in FIG. 18 show that the use of hydrogen-containing co-gas reduces the specific beam current of non-aluminum ion species. Specifically, the beam contains a significantly reduced amount of W + ions and WF x + ions, and these ions can adversely affect the performance and source life of the ion source, for example, by causing "glitching" or eroding the arc chamber exit aperture. Also, the use of hydrogen as a co-flow gas does not cause a significant decrease in the level of Al + in the ion beam.

[0112] FIG. 19 shows tungsten ions (W+ shows the beam current of (), and shows that as the hydrogen level increases, the level of tungsten ions in the resulting ion beam decreases accordingly.

[0113] For the system and method of Example 8, the preferred range of hydrogen may be a range that results in a desirable decrease in tungsten ions (W + ) in the ion beam, which can be an amount of hydrogen of at least 3, 5, 10, or 15 percent as shown in FIGS. 18 and 19. The specific amount of hydrogen used can be balanced with the desired beam current intensity as shown in FIG. 17. An exemplary way to balance a preferably large total beam current (FIG. 17) with a preferably small tungsten ion beam current (FIGS. 18, 19) can be to flow hydrogen (or another hydrogen-containing gas) in an amount within the range of 2 to 60 percent, or from 3 or 5 to 30, 35, 40, or 45 percent.

[0114] Within these ranges, the system can function while suppressing the level of glitching caused by a useful level of hydrogen gas. According to the method of the present invention, the amount of hydrogen used can be selected to result in a decrease in the level of glitching, for example, at least 20, 50, 70, or 80 percent decrease in the level of glitching compared to the amount of glitching that occurs when no hydrogen is included.

[0115] Example 9 (FIG. 20) PF 3 Aluminum oxide or aluminum nitride precursors with fluorine-containing co-gas and various amounts of hydrogen-containing co-gas (H 2 ).

[0116] FIG. 20 shows an experimental example of the Al 3 beam current obtained by using solid aluminum oxide or aluminum nitride as a solid aluminum target, PF + fluorine-containing co-gas, and various amounts of hydrogen-containing co-gas.

[0117] The results in Fig. 20 show that the weight change of the cathode decreases in the presence of a certain amount of hydrogen-containing coke oven gas. The weight change of the cathode during the operation of the ion source can indicate the level of tungsten deposition on the cathode.

Claims

1. 1. A method for producing aluminum ions in an ion source having an ion source chamber, comprising: In an ion source chamber containing an aluminum dopant source, BF ３ , P.F. ３ , P.F. ５ , GeF ４ , XeF ２ , C.F. ４ B ２ F ４ , SiF ４ , Si ２ F ６ , AsF ３ , AsF ５ , XeF ４ , XeF ６ , W.F. ６ , MoF ６ , C ｎ F ２ｎ＋２ , C ｎ F ２ｎ , C ｎ F ２ｎ－２ , C ｎ H ｘ F ２ｎ＋２－ｘ , C ｎ H ｘ F ２ｎ－ｘ , C ｎ H ｘ F ２ｎ－２－ｘ (n=1, 2, 3..., -x=0, 1, 2...), COF ２ , S.F. ６ , S.F. ４ , SeF ６ , N.F. ３ , N ２ F ４ , H.F., F. ２ or a combination thereof; and Hydrogen-containing gas into the ion source chamber; generating aluminum ions in the ion source chamber; A method comprising:

2. 10. The method of claim 1, wherein the aluminum dopant source comprises a solid aluminum target selected from aluminum oxide, aluminum nitride, aluminum carbide, aluminum boride, and combinations thereof.

3. 2. The method of claim 1, wherein the hydrogen-containing gas and the fluorine-containing gas are flowed into the ion source chamber in relative amounts of 2 to 60 percent (by volume) of the hydrogen-containing gas based on the total of the hydrogen-containing gas and the fluorine-containing gas.

4. 2. The method of claim 1, wherein the hydrogen-containing gas and the fluorine-containing gas are flowed into the ion source chamber in relative amounts of 5 to 60 percent (by volume) of the hydrogen-containing gas based on the total of the hydrogen-containing gas and the fluorine-containing gas.

5. 2. The method of claim 1 , wherein flowing the hydrogen-containing gas into the ion source as a co-gas extends an operational lifetime of the ion source by at least 10 percent as compared to an operational lifetime that would result from comparable operation of the ion source without the hydrogen-containing gas.

6. 2. The method of claim 1, wherein flowing the hydrogen-containing gas into the ion source as a co-gas reduces glitching of the ion source by at least 20 percent compared to an amount of glitching that would result from comparable operation of the ion source without the hydrogen-containing gas.

7. 10. The method of claim 1, wherein a maximum beam current occurs within a range of from greater than 0 to 60 percent hydrogen containing gas, and the hydrogen containing gas is flowed in an amount within the 60 percentile of the maximum beam current.

8. 10. The method of claim 1, comprising generating neutral or ionized fluorine-containing species from the fluorine-containing gas, and reacting the fluorine-containing species with an aluminum target to generate aluminum ions.

9. the ion source chamber comprising: an interior defined by an interior surface including a sidewall, a bottom, and a top; a cathode and an anticathode in the interior; Equipped with the interior surface comprises tungsten or molybdenum; The method of claim 1.

10. During the generation of the aluminum ions, non-aluminum ions are also generated, and the non-aluminum ions are converted into tungsten ions (W ＋ ) or molybdenum (Mo ＋ ), tungsten or molybdenum fluoride ion (WF ｘ ＋ , MoF ｘ ＋ ) (x=1, 2, 3, 4, or 5), or both; The hydrogen-containing gas is mixed with the tungsten ions (W ＋ ) or molybdenum (Mo ＋ ), tungsten or molybdenum fluoride ion (WF ｘ ＋ , MoF ｘ ＋ ), or decreasing the amount of both, 10. The method of claim 9.

11. The fluorine-containing gas is PF ３ , P.F. ５ , or GeF ４ and The hydrogen-containing gas is H ２ That is, The method of claim 1.

12. The fluorine-containing gas is PF ５ and The hydrogen-containing gas is H ２ That is, The method of claim 1.

13. The hydrogen-containing gas is H ２ , P.H. ３ , A.S.H. ３ , SiH ４ , B ２ H ６ , C.H. ４ , N.H. ３ , GeH ４ , or A ｘ H ｙ 2. The method of claim 1, wherein A is any element except H, and x, y=1, 2, 3, 4, 5, 6, 7, 8, 8, or 10, and combinations thereof.

14. 1. A method for forming aluminum ions in an ion source chamber, comprising: P.F. ３ and P.F. ５ flowing a fluorine-containing gas selected from the group consisting of: generating aluminum ions in the ion source chamber; A method comprising:

15. 15. The method of claim 14, wherein the aluminum dopant source comprises a solid aluminum target selected from aluminum oxide, aluminum nitride, aluminum carbide, aluminum boride, and combinations thereof.

16. The method of claim 14 comprising flowing a hydrogen-containing gas into the ion source chamber.

17. The hydrogen-containing gas is H ２ , P.H. ３ , A.S.H. ３ , SiH ４ , B ２ H ６ , C.H. ４ , N.H. ３ , GeH ４ , A ｘ H ｙ 17. The method of claim 16, wherein A is any element except H, and x, y=1, 2, 3, 4, 5, 6, 7, 8, 8, or 10, and combinations thereof.

18. PF in a relative amount of hydrogen-containing gas of 2 to 60 percent (by volume) based on the total of hydrogen-containing gas and fluorine-containing gas. ５ and flowing the hydrogen-containing gas into the ion source chamber.

19. PF in a relative amount of hydrogen-containing gas of 2 to 60 percent (by volume) based on the total of hydrogen-containing gas and fluorine-containing gas. ３ and flowing the hydrogen-containing gas into the ion source chamber.

20. 15. The method of claim 14, comprising generating neutral or ionized fluorine-containing species from the fluorine-containing gas, and reacting the fluorine-containing species with the aluminum dopant source to generate aluminum ions.

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