JP6412573B2 - How to process a workpiece - Google Patents

Description

  This application claims priority from US Provisional Patent Application No. 61 / 847,776, filed July 18, 2013, the disclosure of which is incorporated herein by reference.

  Embodiments of the present disclosure relate to a method for improving the quality of an ion beam in an ion implantation system, and more particularly to a method for improving the quality of a boron ion beam.

  Semiconductor workpieces are often implanted with dopant species to produce the desired conductivity. For example, a solar cell can be implanted with dopant species to create an emitter region. This injection can be performed using a wide variety of mechanisms. In one embodiment, an ion source is used. The ion source may include a chamber that ionizes the source gas. Ions from these source gases can be extracted from the chamber opening using one or more electrodes. These extracted ions are directed to the workpiece and injected into the workpiece to form a solar cell.

  To increase process efficiency and reduce costs, in some embodiments, ions extracted from the ion source are accelerated directly toward the workpiece without mass analysis. In other words, ions generated by the ion source are accelerated and directly injected into the workpiece. Mass analyzers are used to remove unwanted species from the ion beam. Removal of the mass analyzer means that all ions extracted from the ion source are injected into the workpiece. Thus, in that case, undesirable species that may be generated in the ion source are also injected into the workpiece.

  This phenomenon is most noticeable when the source gas is a halogen-based compound, such as a fluoride. Fluorine ions and neutrals (metastable or excited states) can react with the inner surface of the ion source and release undesirable ions such as silicon, oxygen, carbon, aluminum, and heavy metals present as impurity elements.

  Thus, a method for improving beam quality is particularly beneficial for embodiments using halogen-based source gases.

  A method of processing a workpiece is disclosed, which method first coats an ion chamber with a desired dopant species and other species. Following this conditioning process, a feed gas containing fluorine and the desired dopant species is introduced into the chamber and ionized. Thereafter, ions are extracted from the chamber, accelerated toward the workpiece, and first injected into the workpiece without mass analysis. Other species used during the conditioning process may be Group 3, 4 or 5 elements. The desired dopant species can be boron.

  In one embodiment, a method for processing a workpiece is disclosed. The method comprises introducing a conditioning gas into a chamber of an ion source, wherein the conditioning gas includes a hydride containing a desired dopant species and a conditioning cogas, the conditioning cogas comprising a hydride of a Group 4 element or 10% to 40% of the total amount of gas introduced comprises a hydride of the species having the opposite conductivity of the desired dopant species, and the conditioning gas and the conditioning cogas are fed into the chamber Forming a coating on the wall of the chamber by ionizing within, changing a gas introduced into the chamber after the coating is formed, and supplying a feed gas containing fluorine and the desired dopant species Introducing into the chamber; and Generating ions in the chamber and extracting the ions from the chamber and accelerating towards the workpiece so that the ions are injected into the workpiece without mass analysis. .

  In the second embodiment, a workpiece processing method is disclosed. The method comprises introducing a conditioning gas into a chamber of an ion source, wherein the conditioning gas includes borane and a conditioning co-gas, the conditioning co-gas includes a hydride of a group 4 or group 5 element, and Forming a coating of borane and the Group 4 or Group 5 element on the wall of the chamber; and introducing a feed gas containing fluorine and boron into the chamber after the coating is formed. And ionizing the feed gas in the chamber to generate ions, and extracting the ions from the chamber and accelerating them toward the workpiece.

In a third embodiment, a method of processing a workpiece is disclosed that performs a conditioning process on the ion source chamber to coat the walls of the ion source chamber with boron and a Group 4 or Group 5 element. And performing an implantation process after a coating is formed on the wall, wherein in the implantation process, a feed gas comprising fluorine and boron is ionized to generate ions, and the ions are introduced into the chamber. And is accelerated toward the workpiece, and the ions are injected into the workpiece without mass spectrometry. In some embodiments, the conditioning process comprises ionizing a conditioning gas comprising borane and a conditioning cogas comprising a hydride of the Group 4 element or Group 5 element. In some other embodiments, the conditioning co-gas can be phosphine (PH ₃ ), arsine (AsH ₄ ), germane (GeH ₄ ), or silane (SiH ₄ ).

  For a better understanding of the present disclosure, please refer to the accompanying drawings, which are incorporated herein by reference.

1 shows one injection system of different embodiments. Fig. 5 shows another injection system of a different embodiment. Fig. 4 shows yet another injection system of a different embodiment. Figure 5 is a graph showing dopant current and contamination level as a function of dilution gas concentration. (A) and (B) are graphs showing the ratio of contaminants to total beam current when two different conditioning processes are used. (A), (B) is a figure which shows the difference of two conditioning processes.

  As mentioned above, ionization of halogen-based species, such as fluoride, can inject particles released from the inner surface of the ion source into the workpiece. These contaminants may include aluminum, carbon, nitrogen, oxygen, silicon, halogen-based compounds, and other undesirable species (such as heavy metals present as impurity elements). One way to deal with damage due to free halogen ions is to introduce a second source gas during implantation.

  1A-1C illustrate various embodiments in which a second source gas can be introduced into the chamber 105 of the ion source 100. FIG. In each of these figures, the ion source 100 includes a chamber 105 defined by a number of plasma chamber walls 107, which may be composed of graphite or other suitable material. One or more source gases stored in the source gas container 170 may be supplied to the chamber 105 via the gas inlet 110. This source gas may be excited by the RF antenna 120 or other mechanism. The RF antenna 120 is in electrical communication with an RF power source (not shown) that supplies power to the RF antenna 120. A dielectric window 125 such as a quartz window or an alumina window may be disposed between the RF antenna 120 and the inside of the ion source 100. The ion source 100 also includes an opening 140 through which ions can pass. In order to extract positively charged particles from within the chamber 105 through the opening 140 toward the workpiece 160, a negative voltage is supplied to an extraction (extraction) electrode disposed outside the opening 140. In some embodiments, the opening 140 is located on the opposite side of the ion source 100 from the dielectric window 125 side. Ions extracted from the chamber 105 are formed into an ion beam 180 and directed to the workpiece 160. As described above, a mass analyzer that filters ions before they strike the workpiece 160 is not used. In one particular embodiment shown in FIG. 1A, a second source gas can be stored in the second gas container 175 and introduced into the chamber 105 via the second gas inlet 111. In another embodiment shown in FIG. 1B, a second source gas may be stored in the second gas container 176 and introduced into the chamber 105 via the same gas inlet 110 used for the first source gas. In yet another embodiment shown in FIG. 1C, the second source gas may be mixed with the first source gas in a single gas container 178. This mixed gas can be introduced into the chamber 105 via the gas inlet 110.

  In any of these embodiments, the first source gas and the second source gas may be introduced into the chamber 105 simultaneously or sequentially.

The first source gas is also called a feed gas and can contain a dopant such as boron in combination with fluorine. Thus, the feed gas may be in the form of DF _n or D _m F _n , where D represents a dopant atom and may be boron, gallium, phosphorus or arsenic, or a group 3 or group 5 element. The second source gas is also referred to as a diluent gas, it can be a molecule having the chemical formula of XH _n or X _m H _n, where H is hydrogen. X can be a dopant species, such as any of the elements described above. Alternatively, X may be an atom that does not affect the conductivity of the workpiece 160. For example, when the workpiece 160 is made of silicon, X may be a group 4 element such as silicon and gallium.

In other words, the feed gas can be BF ₃ or B ₂ F ₄ , while the diluent gas can be, for example, PH ₃ , SiH ₄ , NH ₃ , GeH ₄ , B ₂ H ₆ , or AsH ₃ . This list shows some possible species that can be used. Of course, other feed gas and dilution gas species are possible.

  By mixing the feed gas with the diluent gas, the adverse effects of fluorine ions can be reduced. For example, without being limited to any particular theory, the introduction of hydrogen can produce a coating or coating on the dielectric window 125. This helps protect the dielectric window 125 and reduces the amount of contaminants generated from the dielectric window 125 that are incorporated into the extracted ion beam 180. In addition, the dilution gas can coat the inner surface of the plasma chamber wall 107, which can be another source of contamination. This coating can reduce the interaction between the fluorine ions and the inner surface of the plasma chamber wall 107 and can reduce the amount of contaminants produced.

The introduction of a diluent gas can reduce the generation of contaminants and the incorporation of these contaminants into the ion beam. Conversely, the introduction of a large amount of diluent gas can adversely affect the production of dopant ions used in the ion beam. For example, the introduction of an excessive amount of diluent gas can reduce the dopant beam current generated in the ion source. In addition, an excessive amount of dilution gas containing hydrogen can cause etching and cause additional contamination. Hydrogen is known to etch several materials. For example, hydrogen can react with graphite walls to produce CH _x gas.

  Surprisingly, it was confirmed that the reduction in contamination did not decrease in proportion to the increase in dilution gas concentration. In other words, when the amount of dilution gas increases above a predetermined threshold, the ratio of contamination current to dopant current actually increases. This may be due to the fact that above a predetermined threshold, the additional coating on the inner surface of the plasma chamber wall 107 provides little or no additional protection against fluorine. In addition, plasma parameters, such as high plasma voltage, can change with a high dilution gas rate and cause additional sputtering of the chamber walls by dilution gas ions. In addition, high dilution gas rates can cause wall material etching and add contamination. Additional sputtering of the chamber walls can result in increased contamination levels. Thus, as the dopant current decreases as a function of dilution gas concentration, and the contamination concentration remains constant or increases after a predetermined threshold, the proportion of contaminants in the ion beam necessarily increases.

  FIG. 2 shows a representative graph showing the effect of dilution gas concentration on both the dopant beam current and the contaminant to dopant ratio in the ion beam. As noted above, the contaminant may be an ionic species such as silicon, nitrogen, oxygen, hydrogen, aluminum, carbon, carbon compounds, fluorine, fluorine compounds, or other non-dopant species.

As shown in FIG. 2, the dopant current represented by the bar graph is maximum when no diluent gas is present. Dopant current decreases almost linearly as the concentration of the diluent gas is GeH ₄ increases in this example. Although this graph shows a specific relationship between dopant current and dilution gas concentration, this relationship may be specific to the test conditions used. For example, different dilution gases, different RF power levels, or different pressures (or flow rates) in the plasma chamber can produce different results. This bar graph is therefore intended to represent a general trend between dopant current and diluent gas concentration.

Curve 300 shows a measurement of beam impurity, defined as a specific contaminant to dopant ratio in the ion beam, where the contaminant can be one of those specified above. As expected, beam impurity decreases as the dilution gas concentration increases from 0% to 10%. As mentioned above, this can be attributed to the covering action of hydrogen in the dilution gas. Other species in the dilution gas may provide a coating action. For example, in the case of GeH ₄ , the hydrogen molecules are light and are therefore rapidly released. However, since GeH ₄ is a heavy molecule with attached hydrogen, it takes a long time to transport and increases the probability of reacting with and coating the chamber surfaces. For example, a compound having a composition such as GeH ₄ may coat the wall and protect the wall material from fluorine etching. Surprisingly, however, the beam impurity remains relatively flat until the dilution gas concentration reaches about 30%. In other words, despite the introduction of a larger amount of diluent gas, the amount of contaminant relative to the amount of dopant remains relatively constant. Through the range of about 5% to 30%, the beam impurity is about 1% or less. Surprisingly, as the dilution gas concentration increases above 30%, the beam impurity increases fairly dramatically, reaching levels above 5% when the gas mixture is a 60% dilution gas. Beam impurity can be minimized when the concentration of diluent gas is between 5% and 30%.

  1A-1C use an ion source with an RF antenna 120 and an RF power source to generate the required ions. However, it will be appreciated that other types of ion sources such as IHC, hollow cathode, helicon, and microwave ion sources may be used. For example, in some embodiments, an indirectly heated cathode (IHC) that uses heat to produce thermionic emission of electrons may be used.

As described above, an extracted ion beam 180 with reduced beam impurity can be generated using two source gases. The first source gas, or feed gas, can be a species containing both boron and fluorine, such as BF ₃ or B ₂ F ₄ . The second source gas, ie the diluent gas, can be a species containing either hydrogen and silicon or germanium, such as silane (SiH ₄ ) or germane (GeH ₄ ). These two source gases are introduced simultaneously or sequentially into the chamber 105 of the ion source 100 where they are ionized. The ion source can utilize RF energy generated by the RF antenna 120. In another embodiment, the ion source may utilize thermal thermionic emission of electrons using IHC. Other methods of ionizing the gas may be used with the ion source. These two source gases can be introduced so that 5% to 30% (volume%) of the total gas amount is a dilution gas and the rest is a feed gas. Ions from both source gases are extracted from the opening 140 by the electrodes 130 and 150, accelerated toward the workpiece 160, and injected into the workpiece 160. As described above, these ions are not mass analyzed. That is, all the extracted ions are implanted into the workpiece 160.

In another example, the diluent gas can include a dopant of opposite conductivity. For example, the first source gas, or feed gas, can be a species containing both boron and fluorine, such as BF ₃ or B ₂ F ₄ . The second source gas, i.e. the dilution gas, can be a species comprising hydrogen and a Group 5 element such as phosphorus, nitrogen or arsenic.

  The above disclosure states that the diluent gas ranges from about 5% to 30% of the total gas volume. However, in some embodiments, this range is different. For example, in some embodiments, the dilution gas concentration can be up to 10%, such as 1-10%, 2-10%, 3-10%, or 5-10%. In another embodiment, the dilution gas concentration can be up to 15%, for example 1-15%, 2-15%, 3-15%, 5-15% or 7-15%. In another embodiment, the dilution concentration can be up to 20%, for example 2-20%, 3-20%, 5-20%, 7-20% or 10-20%. In another embodiment, the dilution gas concentration can be up to 30%, such as 3-30%, 5-30%, 7-30%, 10-30%, or 15-30%. In another embodiment, the dilution gas concentration may be up to 40%, for example 3-40%, 5-40%, 7-40%, 10-40%, 15-40% or 20-40%. it can. In another embodiment, the dilution gas concentration may be up to 50%, for example 5-50%, 7-50%, 10-50%, 15-50%, 20-50% or 25-50%. it can. Finally, in another embodiment, the dilution gas concentration is up to 60%, eg 5-60%, 7-60%, 10-60%, 15-60%, 20-60%, 25-60% or It can be 30-60%.

  The above description details how to use a dilution gas with a feed gas to generate a plasma that is used to generate ions that are implanted into the workpiece. However, other techniques can be used in addition to or instead of this method.

  For example, in one embodiment, the inner surface of the chamber wall 107 of the ion source 100 can be conditioned prior to the implantation process. Conditioning is the process of coating the inner surface of these plasma chamber walls 107 with material. This material acts to protect the plasma chamber wall 107 from the adverse effects of halogens and reduces the amount of contaminants that are etched from the plasma chamber wall 107 and introduced into the extracted ion beam.

  Conditioning can be performed in several ways. In the first embodiment, conditioning is performed in the same manner as ion implantation. In other words, plasma is generated in the chamber 105 using energy from the RF antenna 120 or other plasma generator. Ions from the plasma are then extracted from the chamber 105 by applying a bias voltage to the electrodes 130,150. During this time, ions from the unextracted plasma can be deposited on the plasma chamber wall 107 and dielectric window 125 of the chamber 105.

  In the second embodiment, a bias voltage is not applied to the electrodes 130 and 150. In this way, the plasma and ions remain in the chamber 105. Again, ions from the plasma can be deposited on the plasma chamber wall 107 of the chamber 105.

  In either embodiment, this plasma generation produces ions, a portion of which adheres to the inner surface of the plasma chamber wall 107 and produces a coating on those surfaces. Although this conditioning process may run for about 60 minutes, this amount of time is not limited by this disclosure. In other embodiments, the conditioning plasma can be run until a coating of a predetermined thickness is produced.

In some embodiments, a hydride containing the desired dopant species is used to condition the plasma chamber wall 107. The desired dopant species can be the dopant used during the subsequent implantation process. In other words, in scenarios where the feed gas includes boron to be injected into the workpiece during the injection process, borane can be used as the conditioning gas during the conditioning process. The borane can be diborane (B ₂ H ₆ ), pentaborane (B ₅ H ₉ ), decaborane (B ₁₀ H ₁₄ ), or any other borane. Different hydrides can be used as the conditioning gas when different dopants are implanted.

In addition, a conditioning co-gas can be used with the hydride. In some embodiments, the conditioning co-gas can be a noble gas, such as helium, argon, krypton, or xenon. In other embodiments, the conditioning co-gas can be, but is not limited to, a hydride comprising a Group 4 element, such as silicon hydride (silane SiH ₄ ) or germanium hydride (ie, germane GeH ₄ ). In yet other embodiments, the conditioning co-gas can be a hydride comprising a species that is oppositely conductive to the desired dopant. In other words, when the feed gas contains boron, a hydride containing a Group 5 element can be used as a conditioning co-gas. The conditioning co-gas can be phosphine (PH ₃ ) or arsine (AsH ₃ ) in this scenario.

  The content of the co-gas can be changed. For example, in some embodiments, the conditioning co-gas can be 10-40% of the total gas introduced into the chamber 105. In other embodiments, the conditioning co-gas can be 20-40% of the total gas. In still other embodiments, the conditioning co-gas can be about 30% of the total gas introduced during the conditioning process.

In one particular example, BF ₃ or B ₂ F ₄ is used as the feed gas for workpiece injection. Diborane can be used with the conditioning co-gas to condition the plasma chamber wall 107 of the ion source 100. This conditioning co-gas can be, for example, a noble gas such as helium, argon, krypton or xenon, a group 4 hydride such as SH ₄ or GeH _4, or a group 5 hydride such as PH ₃ or AsH ₃ . This list is not exhaustive and, of course, other molecules may be used as conditioning co-gas during the conditioning process.

Surprisingly, the addition of conditioning co-gas during conditioning has a significant effect on the quality of subsequent injections. For example, in one test, the conditioning process was performed on an ion source using only diborane as the conditioning gas. This conditioning was performed for 1 hour. After conditioning, plasma was generated in chamber 105 with RF power of about 3 kW using, for example, a B ₂ F ₄ feed gas, and the workpiece was implanted with a boron-based ion beam. Furthermore, 10% of the total gas introduced during the implantation process was a dilution gas containing GeH ₄ . In this test, an extraction energy of 10 ekV was used. While the workpiece was being implanted, the ion beam was analyzed. It was confirmed that the contamination (ratio to the total beam current) was greater than 1% while B ₂ F ₄ implantation using 10% GeH ₄ as the diluent gas was less than 2 hours. This can be illustrated graphically in FIG. 3A, where the curve 400 represents the proportion of contaminants in the ion beam. Contaminants include, but are not limited to, carbon, nitrogen, oxygen, fluorine, aluminum and compounds containing any of these elements.

In the second test, conditioning was performed using a combination of conditioning gas (diborane) and conditioning co-gas (german). This conditioning was also performed for 1 hour. Similarly, after conditioning, a plasma was generated in chamber 105 using, for example, a B ₂ F ₄ feed gas with a 10% GeH 4 diluent gas, and the workpiece was implanted with a boron-based ion beam. While the workpiece was being implanted, ion beam analysis was performed. Unlike the first test result, in this case the contaminant level was less than 1% of the total beam current even after 9 hours of continuous treatment. This can be illustrated graphically in FIG. 3B, where the curve 410 represents the proportion of contaminants in the ion beam.

In operation, a conditioning cycle is first performed to coat the plasma chamber wall 107 of the ion source 100 with a material. As described above, in some embodiments, this coating is a boron-based material that is produced by introducing borane, such as diborane, into the chamber 105. The conditioning gas is then excited into the plasma, and ions from the plasma adhere to the plasma chamber wall 107 and cover the wall. As mentioned above, a conditioning co-gas can be used with borane to improve the thickness and quality of the conditioning process. This conditioning co-gas can be a noble gas such as helium, argon, krypton or xenon. In other embodiments, the conditioning co-gas can be a hydride containing a Group 5 element, such as PH ₃ or AsH ₃ . In other embodiments, the conditioning co-gas can be a hydride comprising a Group 4 element. This conditioning co-gas can be introduced at least partially simultaneously with borane.

  Because this conditioning process serves to coat the plasma chamber wall 107, impurities and other contaminants contained within the plasma chamber wall 107 are separated from the plasma. This coating contains a dopant contained in the conditioning gas, for example a Group 3 element such as boron. This coating can also contain molecules present in the conditioning co-gas, for example group 4 elements such as germanium or silicon or group 5 elements such as phosphorus or arsenic. A sufficiently thick coating can be applied. The duration of the conditioning process may be based on elapsed time, for example, a one hour conditioning cycle, and may be based on the coating thickness measured as it accumulates on the plasma chamber wall 107. .

The gas supplied to the chamber 105 is then changed to the gas used during the injection process. Specifically, feed gas is introduced. The conditioning gas and the conditioning co-gas may or may not continue to be introduced into the chamber 105. As mentioned above, the feed gas can be a dopant and fluorine containing molecule, such as B ₂ F ₃ or B ₂ F ₄ , but other gases may be used. The dopant used for the implantation process can be the same as described above for the conditioning process. Furthermore, a dilution gas can also be supplied to the chamber 105 during the injection process. The diluent gas may be, but is not limited to, a hydride containing a Group 3, 4 or 5 element, such as B ₂ H ₆ , GeH ₄ , SH ₄ , PH ₃ , AsH ₃ . As described above, in scenarios where the desired dopant species is a Group 3 element, the diluent gas may include a Group 4 or Group 5 element. In some embodiments, the diluent gas and the conditioning co-gas can be the same gas. In other embodiments, the dilution gas and the conditioning can be the same gas. In still other embodiments, the dilution gas may include both a conditioning gas and a conditioning co-gas. The implanted gas is then excited into the plasma, and ions are extracted from the plasma by applying a bias voltage to the electrode 130. The extracted ions are then directed to the workpiece and injected into the workpiece without first being mass analyzed.

  This implantation process may be used for a plurality of workpieces 160 and may continue for a specific period of time or may be stopped when the level of contaminant in the extracted ion beam reaches a predetermined level. Good. For example, the implantation process can continue until the contaminant level reaches about 1% of the total beam current, although other contamination levels may be selected. 4A and 4B show a comparison of two different conditioning processes. In the first embodiment shown in FIG. 4A, the conditioning is performed using only diborane as the conditioning gas. Conditioning is performed for 1 hour, after which the infusion process is started. The injection process ends when the contaminant level reaches a predetermined level, for example 1%. As can be seen, this results in a duty cycle of about 50%, and conditioning the chamber 105 spends the same amount of time as workpiece injection. In a second embodiment shown in FIG. 4B, conditioning is performed using diborane with a conditioning co-gas (which can be germane in this example). As shown in FIG. 3B, this combination can withstand the adverse effects of halogens and increase the implantation time. In this particular example, the conditioning process was run for 1 hour, and then the infusion process was run for about 9 hours. After 9 hours, the contaminant level was equal to or lower than the predetermined level. In other words, the duty cycle (injection execution time / total usage time) in this particular embodiment is about 90%. This difference in duty cycle is extremely important. In other words, in a 10 day period, at 90% duty cycle, the infusion is performed over 216 hours. In contrast, at a 50% duty cycle, an 18 day period is required to achieve the same infusion time. This directly reflects work efficiency and the cost of each workpiece. This example is illustrative and results may vary depending on the choice of different gases and / or implantation energies.

  It is surprising that these various gases and co-gas can be used in an ion implantation system that does not use mass spectrometry, and all of the ions generated in the chamber are ultimately injected into the workpiece. It is unpredictable that species other than the dopant species can be used without adversely affecting the workpiece during both the conditioning and implantation processes.

The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, in addition to the embodiments set forth herein, various other embodiments and modifications of the disclosure will be apparent to those skilled in the art from the foregoing description and accompanying drawings. Accordingly, such other embodiments and modifications are intended to be included within the scope of this disclosure. Further, although the present disclosure has been described herein in the context of a specific implementation for a specific purpose in a specific environment, those skilled in the art will not be limited in their usefulness by the present disclosure. Will recognize that it can be beneficially implemented for some purposes in some environments. Accordingly, the claims set forth below should be construed in view of the full scope and spirit of the present disclosure as described herein.

Claims (14)

A method of processing a workpiece, comprising:
Introducing a conditioning gas into the chamber of the ion source, the conditioning gas comprising a hydride containing a desired dopant species and a conditioning co-gas, the conditioning co-gas being a rare gas, a hydride of a group 4 element or Including a hydride of a species having a conductivity opposite to the desired dopant species, wherein 10% to 40% of the total amount of gas introduced is the conditioning co-gas;
Ionizing the conditioning gas and the conditioning co-gas in the chamber to form a coating on the walls of the chamber;
Changing the gas introduced into the chamber after the coating is formed, and introducing a feed gas comprising fluorine and the desired dopant species into the chamber;
Ionizing the feed gas in the chamber to generate ions;
Extracting the ions from the chamber and accelerating towards the workpiece such that the ions are injected into the workpiece without mass spectrometry;
A method comprising:   The method of claim 1, wherein the desired dopant species comprises boron.   The method of claim 2, wherein the conditioning co-gas comprises a hydride of a Group 4 element.   The method of claim 2, wherein the conditioning co-gas comprises a hydride of a Group 5 element.   The method of claim 2, wherein the conditioning co-gas comprises a noble gas. A method of processing a workpiece, comprising:
Introducing a conditioning gas into a chamber of an ion source, wherein the conditioning gas includes borane and a conditioning co-gas, and the conditioning co-gas includes a hydride of a group 4 or group 5 element;
Forming a coating of borane and the Group 4 or Group 5 element on the wall of the chamber;
Introducing a feed gas comprising fluorine and boron into the chamber after the coating is formed;
Ionizing the feed gas in the chamber to generate ions;
Extracting the ions from the chamber and accelerating towards the workpiece;
A method comprising:   The method of claim 6, wherein the ions are implanted into the workpiece without mass spectrometry.   A dilution gas is introduced into the chamber along with the feed gas, the dilution gas comprising a hydride of a group 4 or 5 element, and the method further ionizes the dilution gas in the chamber to generate ions. The method of claim 6 comprising the step of:   The method of claim 6, wherein the coating is formed by ionizing the conditioning gas and the conditioning co-gas in the chamber. A method of processing a workpiece, comprising:
Performing a conditioning process in the ion source chamber to coat the walls of the ion source chamber with boron and a Group 4 or Group 5 element;
Performing an injection process after a coating has been formed on the wall;
In the implantation process, a feed gas containing fluorine and boron is ionized to generate ions, the ions are extracted from the chamber, accelerated toward the workpiece, and the ions are implanted into the workpiece without mass spectrometry To
Method.   The method of claim 10, wherein the conditioning process comprises ionizing a conditioning gas comprising borane and a conditioning co-gas comprising a Group 4 or Group 5 element hydride in the chamber.   The method of claim 11, wherein the conditioning co-gas comprises phosphine or arsine.   The method of claim 11, wherein the conditioning co-gas comprises germane or silane.   The method of claim 10, wherein the extracted ions form an ion beam, and the method further comprises repeating the conditioning process when a percentage of contaminants in the ion beam exceeds a predetermined threshold.

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