METHOD AND ARRANGEMENT FOR DETERMINING THE CARBON CONTENT IN SILICON

Abstract

Method for determining the carbon content in a silicon sample (102), the method comprising the following: Generating electrically active polyatomic complexes within the silicon sample (102), wherein the polyatomic complexes comprise at least one carbon atom, at least one oxygen atom and at least one hydrogen atom; Determining a quantity that is indicative of the content of the generated polyatomic complexes in the silicon sample (102); and Determining the carbon content in the silicon sample (102) from the determined quantity, where at least some of the polyatomic complexes are configured as flat donors.

Description

Technical area

[0001] Various embodiments generally relate to methods and measuring arrangements for determining the carbon content in a silicon sample. background

[0002] To achieve a stable doping profile induced by proton irradiation, very low-oxygen zone-melt (ZM) silicon material is required. This, however, comes at the expense of a limited wafer diameter, as the production of ZM silicon for wafers with a diameter of 300 mm and larger, which are required for various applications, is not feasible. Therefore, there is particular interest in silicon wafers with a diameter of 300 mm and larger. Wafers with such large diameters can be produced from silicon ingots grown by the Czochralski process, in particular the magnetic Czochralski (MCz) process.

[0003] In MCz silicon, carbon and oxygen are the most common impurities. In the case of proton doping, the final doping concentration is critically affected by the presence of carbon atoms, which are predominantly arranged on substitution lattice sites.

[0004] In the following description, substitution impurities, i.e., impurities located on substitution lattice sites, are designated with an "S." Interstitial impurities are designated with an "I."

[0005] The carbon content in silicon is typically in the range of 5·10 14 up to 1·10 16 cm -3 , which is enough to critically influence the proton-induced doping profiles. Therefore, accurate measurement of the carbon content in this region is necessary to control the final proton-induced doping concentration.

[0006] Traditionally, the carbon content in silicon is determined by SIMS (secondary ion mass spectroscopy) or FTIR (Fourier transform infrared spectroscopy). However, the use of these methods is limited due to their rather high detection limits for carbon contents of approximately 3 10 15 cm -3 limited.

[0007] The sensitivity of FTIR is greatly affected by the interference of the signals from carbon (C S ) and silicon (Si S ) that have nearly the same resonance frequencies, or by the need to use reference samples with known low carbon contents that are not available as industry standards.

[0008] In addition, the conventional FTIR method can only detect substitution carbon atoms C S detect carbon atoms arranged on regular lattice sites. Interstitial carbon atoms C IHowever, carbon particles originating from other high-temperature or irradiation processing steps, which may constitute a significant portion of the carbon present in a silicon sample, are not detectable by this method. This also limits the sensitivity of conventional FTIR techniques.

[0009] Methods for determining the carbon content in a silicon sample are known from: JP 2015 - 156 420 A, Nakamura, M. (et. al.): Photoluminescence Measurement of Carbon in Silicon Crystals Irradiated with High Energy Electrons, J. Electrochem. Soc., Vol. 141, No. 12, pp. 3576-3580, and from Inoue, N. (et. al.): Infrared measurement and irradiation of ultra low carbon concentration silicon crystal, Phys. Status Solidi C 9, No. 10-11, 1931-1936 (2012). Brief description

[0010] According to the present invention, a method according to claim 1 and a measuring arrangement according to claim 15 are provided.

[0011] According to one aspect of the present disclosure, a method for determining the carbon content in a silicon sample is provided. The method comprises generating electrically active polyatomic complexes within the silicon substrate. Each polyatomic complex comprises at least one carbon atom. The method further comprises determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample and determining the carbon content in the silicon sample from the determined quantity.

[0012] According to a second aspect of the present disclosure, a measuring arrangement for determining the carbon content in a silicon sample is provided. The arrangement comprises a polyatomic complex generation unit configured to generate electrically active polyatomic complexes within the silicon sample. Each polyatomic complex comprises at least one carbon atom. The measuring arrangement further comprises a first determination unit configured to determine a quantity indicative of the content of the generated polyatomic complexes in the silicon sample, and a second determination unit configured to determine the carbon content in the silicon sample from the determined quantity. Short description of the drawings

[0013] In the drawings, like reference numerals generally designate the same components throughout the several views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which: Fig. 1 shows low-temperature FTIR spectra of several silicon samples; Fig. 2 an enlarged view of characteristic peaks at 241 cm -1 and 247 cm -1 of two FTIR spectra, which in Fig. 1 are shown; Fig. 3 the dependence of the sum of the intensities of characteristic peaks of polyatomic complexes in a silicon sample at 241 cm -1 and 247 cm -1 of the carbon content in the silicon sample; Fig. 4 shows a flow diagram of an exemplary method for determining the carbon content in a silicon sample; and Fig. 5 shows a schematic view of a measuring arrangement for determining the carbon content in a silicon sample. Description

[0014] The following detailed description refers to the accompanying drawings which show, by way of example, specific details and embodiments in which the invention may be practiced.

[0015] The word "exemplary" as used herein means "serving as a model, example, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily intended to be preferred or advantageous over other embodiments or designs.

[0016] The deficiencies of the conventional method for determining the carbon content in a silicon sample discussed above can be overcome by a method for determining the carbon content in a silicon sample, which comprises: generating electrically active polyatomic complexes within the silicon sample, determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample, and determining the carbon content in the silicon sample from the determined quantity. Each polyatomic complex may comprise at least one carbon atom.

[0017] By this method, the carbon content is determined indirectly by determining a quantity indicative of the content of polyatomic complexes comprising at least one carbon atom, rather than by detecting signals directly emanating from substitution carbon atoms C STherefore, the overlap of signals discussed above, which are emitted by Si S and C S irrelevant for the inventive method and does not limit the achievable sensitivity. In this way, the sensitivity can be increased by almost an order of magnitude compared to the conventional method discussed above, to approximately 5·10 14 cm -3 be improved.

[0018] Before the formation of polyatomic complexes, a significant portion of the carbon atoms present in the silicon sample are found at substitution lattice sites. As indicated in equation (1) below, the generation of polyatomic complexes can involve the rearrangement of carbon atoms from the substitution lattice sites to interstitial sites. This can be achieved by particle irradiation of the silicon sample, particularly with protons and / or electrons and / or neutrons and / or alpha particles. Si I + C S → C I + Si S (1)

[0019] At room temperature (RT), interstitial carbon is unstable due to diffusion, which leads to the capture of migrating interstitial carbon atoms by interstitial oxygen atoms O I which leads to C I O I -interstitial complexes are formed, as given in equation (2). C I + O I → C I O I (2)

[0020] The interstitial complexes C I O I are stable up to 350 °C. According to one aspect of the present invention, higher thermal stability can be achieved by polyatomic interstitial complexes which, in addition to carbon, also contain at least one hydrogen atom H m and / or several interstitial oxygen atoms O nI Here, n, m are integers that represent the number of interstitial oxygen atoms O I or hydrogen atoms H, which are present in an individual polyatomic interstitial complex. Such polyatomic interstitial complexes can therefore contain at least one hydrogen atom H, which was introduced by particle irradiation, and several interstitial oxygen atoms O nIThese polyatomic interstitial complexes are described below with C I O nI -H m designated.

[0021] These complexes are thermally stable up to temperatures above 450 °C. In an exemplary embodiment, at least some or even most of the polyatomic interstitial complexes comprise multiple interstitial oxygen atoms O I and / or at least one hydrogen atom H. The generation efficiency of these interstitial complexes C I O nI -H m can be increased by annealing the silicon sample after its irradiation with particles.

[0022] The annealing may be performed at a temperature in a range of about 450°C to about 520°C. In an exemplary embodiment, the annealing may be performed at a temperature of about 490°C.

[0023] The annealing may be performed for a period of time ranging from about 30 minutes to about 7 hours. In an exemplary embodiment, the annealing may be performed for a period of time ranging from about 1 hour to about 5 hours.

[0024] The polyatomic interstitial complexes discussed above can act as hydrogen-induced shallow thermal donors (STD-H). This means that these polyatomic complexes can generate energy states in the silicon band gap close to the conduction band. The gap between these energy states and the conduction band is smaller than the thermal energy at room temperature.

[0025] In the far infrared (FIR) range, silicon samples containing C I O nI -H m Complexes include significant absorption peaks at 241 cm -1 and 247 cm -1 which are assigned to these complexes.

[0026] The determination of the quantity indicative of the content of polyatomic complexes in the silicon sample can be carried out by a spectroscopic method, in particular by Fourier transform infrared spectroscopy (FTIR).

[0027] FTIR is a spectroscopic technique for determining the ability of a sample to absorb electromagnetic radiation of a given wavelength in the infrared range, which is indicative of the individual composition of the sample being analyzed. FTIR involves irradiating the sample with an infrared light beam of a specified wavelength range. During irradiation, the sample's absorbance is measured, yielding an initial data point. Subsequently, the wavelength range of the light beam is modified several times, and the sample's absorption properties are measured for each light beam, yielding several corresponding data points. The light absorption for each wavelength is then calculated using Fourier transformation. The resulting spectrum includes several characteristic peaks corresponding to the individual components of the sample being analyzed.In this way, the peaks described above at 241 cm. -1 and 247 cm -1 be detected.

[0028] The respective heights and / or integrated areas of the peaks can be determined as the quantity indicative of the content of polyatomic interstitial complexes. Since several characteristic peaks are present in this case, the sum of the integrated areas of the peaks can also be determined as the quantity indicative of the content of polyatomic complexes.

[0029] Peak resolution can be increased by reducing the temperature of the sample being analyzed. FTIR performed at low temperatures is referred to as low-temperature FTIR (LT FTIR). Spectrum acquisition can be performed at a temperature ranging from approximately 4 to 20 K. In an exemplary embodiment, the temperature may be approximately 10 K. Such low temperatures can be provided by liquid helium, which has a temperature of approximately 4 K. Starting from this base temperature, the sample temperature can be increased by ohmic heating to a higher temperature within the above range.

[0030] In the case of polyatomic complexes acting as donors, the sample can be illuminated with visible light at a power of, for example, 100 W during FTIR spectrum acquisition to suppress or even eliminate the compensation of the donors due to acceptors present in the silicon sample. This allows the content of the polyatomic complexes to be determined more accurately.

[0031] In Fig. 1 shows LT-FTIR spectra of differently processed silicon samples. Fig. Figure 1 comprises a total of twelve spectra, grouped into six sets labeled "10," "11," "12," "13," "14," and "15," respectively. Each of the two spectra within each set was acquired from the same silicon sample, but under different illumination conditions. Specifically, the upper spectrum of a given set was acquired from an illuminated silicon sample, and the lower spectrum of a given set was acquired in a dark environment, meaning the sample was not illuminated during spectrum acquisition.

[0032] The details of the Fig. 1 The spectra groups shown are: 10: low carbon content, not irradiated with particles, not tempered, 11: high carbon content, not irradiated with particles, not tempered, 12: low carbon content, proton irradiated, not annealed, 13: high carbon content, irradiated with protons, not annealed, 14: low carbon content, irradiated with protons and annealed, 15: high carbon content, irradiated with protons and annealed.

[0033] Here, a low carbon content refers to a carbon content of approximately 1·10 15 cm -3 , and a high carbon content refers to a carbon content of approximately 3.3·10 15 cm -3 ,

[0034] The characteristic peaks at 241 cm -1 and at 247 cm -1 , which are the polyatomic complexes C I O nI -H m are assigned to Fig. 1 indicated by the vertical lines. As in Fig. 1, only the spectra of groups “14” and “15” show characteristic absorption peaks at 241 cm -1 and at 247 cm -1. In addition, the heights and areas of the characteristic peaks are correlated with the carbon contents of the individual silicon samples, ie, the heights and areas of the characteristic peaks increase with increasing carbon content. This correlation is shown in Fig. 2, in which only the characteristic peaks at 241 cm -1 and at 247 cm -1 The respective upper FTIR spectra of groups "14" and "15" are shown. The baselines of the spectra were aligned to more clearly show the different heights of the characteristic peaks, which correspond to different carbon contents.

[0035] As previously discussed, a quantity which is responsible for the content of complexes C I O nI -H m in the silicon sample, the sum of the areas of these characteristic peaks can be determined.

[0036] From the sum of the areas of these characteristic peaks, a corresponding carbon content can be derived using a calibration curve, which assigns a unique carbon content to the determined sum of peak areas.

[0037] A calibration curve can be determined in advance using several silicon samples with known carbon contents, measured, for example, by another LT-FTIR method (see, e.g., BH Ch. Alt, et al., Journal of The Electrochemical Society, 150 (8) G498 to G501 (2003)). These samples can be subjected to the procedure discussed above for generating the polyatomic complexes, i.e., particle irradiation and annealing. The absorption properties of the respective samples can then be determined by LT-FTIR, which provides the respective peak areas that can be assigned to the known carbon contents.

[0038] The relationship between the sum of the characteristic peaks of the C discussed above I O nI -H m -complexes and the corresponding carbon contents are shown in Fig. 3. By fitting a compensation function to these data values, a calibration curve can be derived.

[0039] In Fig. 3, a linear function of the general form y = mx + t was fitted to the measured data points, which yields a value of 5·10 -14 for m and -0.0006 for t. The assumed linear relationship between the sum of the peak areas and the carbon content is expressed by an R 2 -value of 0.9843, which indicates a high quality of fit.

[0040] The fitting function can be used to assign a measured sum of peak areas to a corresponding carbon content. This also allows extrapolation down to low carbon contents for which no industry standards—i.e., samples with a known carbon content—are available. The error according to such an extrapolation is minor due to the high quality of the fit.

[0041] The specific quantity indicative of carbon content, such as the heights and integrated areas of the characteristic peaks obtained by FTIR, may also depend on the oxygen content of the sample to be analyzed.

[0042] The oxygen content can be observed using a respective calibration curve. In an exemplary embodiment, multiple sets of standards with known carbon contents and a known fixed oxygen content for each set can be used to derive multiple calibration curves for different oxygen contents. The oxygen concentration in silicon can be easily and very accurately measured using room-temperature FTIR (RT-FTIR).

[0043] In practice, the oxygen content in silicon can be precisely controlled. Therefore, for a given application, large variations in oxygen content between different samples can be avoided. Consequently, the influence of variations in oxygen content on the accuracy of carbon content determination according to the present method can essentially be ignored.

[0044] In Fig. 4 shows a flow diagram of an exemplary method 10 for detecting the carbon content in a silicon sample, which summarizes what has been described above.

[0045] Method 10 may include: Irradiating a silicon sample with protons (12), Annealing the sample (14), Recording an absorption spectrum of the annealed silicon sample using low-temperature FTIR (16), Identifying characteristic absorption peaks in the spectrum (18), Determining the integrated area of ​​the identified characteristic peaks (20), and Determination of the carbon content in the silicon sample from the determined integrated peak area (22).

[0046] The methods described above can be particularly applied to Czochralski silicon samples due to their higher oxygen content compared to zone-melt silicon. A high oxygen content can be advantageous for the generation of a large number of the polyatomic complexes described above, which include interstitial oxygen atoms as carbon capture sites.

[0047] In the Czochralski process, polycrystalline silicon fragments are melted inside a silica crucible. Silicon single crystals are grown by slowly pulling a seed crystal from the molten silicon. This creates an ingot from which wafers can be cut in subsequent process steps.

[0048] In an exemplary embodiment, the silicon sample can be grown using the magnetic Czochralski (MCz) method. This method is similar to the conventional Czochralski method, except that the ingot is grown in a strong magnetic field, which is used to dampen oscillations in the silicon melt. Specifically, in the magnetic Czochralski method, the Lorentz force resulting from the applied magnetic field influences the flow of molten silicon in the crucible and reduces the amplitude of fluctuations in the melt. This allows for better control of the oxygen concentration.

[0049] In Fig. Figure 5 shows a schematic drawing of a measuring arrangement 100 for determining the carbon content in a silicon sample 102 according to the method described above. The above explanations regarding the method also refer to a measuring arrangement 100.

[0050] As in Fig. 5, the measuring arrangement 100 may include a polyatomic complex generation unit 104 configured to generate the electrically active polyatomic complexes within the silicon sample 102, a first determination unit 106 configured to determine the quantity indicative of the content of the generated polyatomic complexes in the silicon sample 102, and a second determination unit 108 configured to determine the carbon content in the silicon sample 102 from the determined quantity.

[0051] The polyatomic complex generation unit 100 may comprise an irradiation subunit 111 configured to irradiate the silicon sample 102 with particles 112, such as protons and / or electrons and / or neutrons and / or alpha particles. As shown in Fig. 5, the irradiation subunit 111 may comprise a particle source 114, such as a hydrogen cell, which emits protons 112, which can be accelerated by an electric field toward the silicon sample 102.

[0052] The polyatomic complex generation unit 104 may further comprise an annealing subunit 116 configured to anneal the silicon sample 102 at temperatures of several hundred degrees Kelvin, as discussed above with respect to the method.

[0053] The first determination unit 106 may include a spectrometer 118 for determining the quantity indicative of the content of polyatomic complexes in the silicon sample 102. The spectrometer 118 may be configured as an FTIR spectrometer. As also discussed above, the resolution of the FTIR spectrometer may be improved by operating the spectrometer 118 at low temperatures, such as in a range of approximately 4 K to approximately 20 K. Such low temperatures may be provided by a liquid He cryostat 120 configured to house the FTIR spectrometer 118.

[0054] The first determination unit 106 may include illumination means 122 configured to irradiate the silicon sample 102 in the spectrometer 118 with visible light to reduce the compensating effect of the acceptors present in the silicon sample 102 on the polyatomic complexes, which may act as flat thermal donors. The illumination means 122 may be configured as an LED. The illumination means 122 may be operated at the low temperatures of the cryostat 120, as shown in Fig. 5. Alternatively, the illuminating means 122 may be operated at room temperature, and the light output from the illuminating means 122 may be introduced into the cryostat through an optical fiber.

[0055] The signals acquired by the spectrometer 118 can be transmitted via data lines 124 to a processing unit 126, such as a computer. The processing unit 126 can be equipped with suitable software to generate a spectrum 128 from the data received from the spectrometer 118.

[0056] The processing unit 126 may also be configured to determine at least one characteristic peak emanating from the polyatomic complexes in the spectrum 128 and to determine, as the quantity indicative of the content of the polyatomic complexes in the silicon sample 102, the height of the at least one identified characteristic peak and / or the area under the at least one identified characteristic peak.

[0057] In an exemplary embodiment, the processing unit 126 may be configured to identify a plurality of characteristic peaks emanating from the polyatomic interstitial complexes and to determine the quantity indicative of the content of the polyatomic complexes in the silicon sample 102 as the sum of the areas under the plurality of characteristic peaks.

[0058] The second determination unit 108 may be configured to determine the carbon content in the silicon sample 102 using a calibration curve that assigns a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample 102.

[0059] Since the determination of the carbon content in the silicon sample 102 can be influenced by the oxygen content in the silicon sample 102, the second determination unit 108 can be configured to select the calibration curve depending on the oxygen content in the silicon sample 102.

[0060] It should be noted that although the first determination unit 106 and the second determination unit 108 have been described as two different units, a measuring arrangement is conceivable that includes a unit configured to both determine the quantity indicative of the content of the polyatomic complexes and to determine the carbon content from the determined quantity. Such a unit can be configured as a computer equipped with suitable software to achieve these tasks from the signals input from the spectrometer 118.

[0061] The following illustrates various aspects of the present disclosure:

[0062] Example 1 is a method for determining the carbon content in a silicon sample. The method comprises generating electrically active polyatomic complexes within the silicon sample. Each polyatomic complex comprises at least one carbon atom. The method further comprises determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample, and determining the carbon content in the silicon sample from the determined quantity.

[0063] In Example 2, the subject matter of Example 1 may optionally further comprise that at least one polyatomic complex, several polyatomic complexes or most polyatomic complexes comprise / comprise at least one oxygen atom or several oxygen atoms.

[0064] In Example 3, the subject matter of any of Examples 1 or 2 may optionally further comprise that generating the polyatomic complexes comprises rearranging carbon atoms from substitutional lattice sites to interstitial lattice sites.

[0065] In Example 4, the subject matter of Example 3 may optionally further comprise that the rearrangement is carried out by particle irradiation of the silicon sample.

[0066] In Example 5, the subject matter of Example 4 may optionally further comprise that the particles comprise protons and / or electrons and / or neutrons and / or alpha particles.

[0067] In Example 6, the subject matter of any of Examples 1 to 5 may optionally further comprise that generating the polyatomic complexes comprises annealing the silicon sample.

[0068] In Example 7, the subject matter of Example 6 may optionally further include performing the annealing at a temperature in a range of about 450°C to about 520°C.

[0069] In Example 8, the subject matter of Example 7 may optionally further include conducting the annealing at a temperature of about 490°C.

[0070] In Example 9, the subject matter of any of Examples 6 to 8 can optionally further comprise conducting the annealing for a period of time ranging from about 30 minutes to about 7 hours.

[0071] In Example 10, the subject matter of Example 9 may optionally further include conducting the annealing for a period of about 1 to 5 hours.

[0072] In Example 11, the subject matter of any of Examples 1 to 10 may optionally further comprise that at least some of the polyatomic complexes comprise at least one hydrogen atom.

[0073] In Example 12, the subject matter of any of Examples 1 to 11 may optionally further comprise at least some of the polyatomic complexes being configured as flat donors.

[0074] In Example 13, the subject matter of any of Examples 1 to 12 may optionally further comprise determining the quantity indicative of the content of the polyatomic complexes in the silicon sample by a spectroscopic method.

[0075] In Example 14, the subject matter of Example 13 may optionally further comprise that the spectroscopic method comprises Fourier transform infrared spectroscopy (FTIR).

[0076] In Example 15, the subject matter of Example 14 may optionally further include performing Fourier transform infrared spectroscopy (FTIR) at a temperature in a range of about 4 K to about 20 K.

[0077] In Example 16, the subject matter of Example 15 may optionally further comprise performing Fourier transform infrared spectroscopy (FTIR) at a temperature of about 10 K.

[0078] In Example 17, the subject matter of any of Examples 13 to 16 may optionally further comprise irradiating the silicon sample with visible light during the determination of the quantity indicative of the content of the polyatomic complexes.

[0079] In Example 18, the subject matter of any of Examples 13 to 17 may optionally further comprise: identifying at least one characteristic peak in a spectrum obtained by the spectroscopic method.

[0080] In Example 19, the subject matter of Example 18 may optionally further comprise determining the quantity indicative of the content of the polyatomic complexes in the silicon sample as the height of the identified at least one characteristic peak and / or as the integrated area of ​​the identified at least one characteristic peak.

[0081] In Example 20, the subject matter of Examples 18 and 19 may optionally further comprise that the spectroscopic method comprises identifying a plurality of characteristic peaks and determining the quantity indicative of the content of the polyatomic complexes in the silicon sample as the sum of the integrated areas under the plurality of characteristic peaks.

[0082] In Example 21, the subject matter of any of Examples 1 to 20 may optionally further comprise determining the carbon content in the silicon sample using a calibration curve that assigns a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample.

[0083] In Example 22, the subject matter of Example 21 may optionally further include selecting the calibration curve depending on the oxygen content in the silicon sample to be analyzed.

[0084] In Example 23, the subject matter of Example 22 may optionally further include determining the oxygen content in the silicon sample to be analyzed by Fourier transform infrared spectroscopy (FTIR).

[0085] In Example 24, the subject matter of Example 22 may optionally further comprise determining the oxygen content by Fourier transform infrared spectroscopy (FTIR) performed at room temperature.

[0086] In Example 25, the subject matter of any of Examples 1 to 24 may optionally further comprise growing the silicon sample by the Czochralski method.

[0087] In Example 26, the subject matter of Example 25 may optionally further include growing the silicon sample by the magnetic Czochralski method.

[0088] Example 27 is a measuring arrangement for determining the carbon content in a silicon sample. The arrangement comprises: a polyatomic complex generation unit configured to generate electrically active polyatomic complexes within the silicon sample. Each polyatomic complex comprises at least one carbon atom. The measuring arrangement further comprises a first determination unit configured to determine a quantity indicative of the content of the generated polyatomic complexes in the silicon sample, and a second determination unit configured to determine the carbon content in the silicon sample from the determined quantity.

[0089] In Example 28, the subject matter of Example 27 may optionally further comprise that at least one polyatomic complex, multiple polyatomic complexes, or most polyatomic complexes comprise(s) at least one oxygen atom or multiple oxygen atoms.

[0090] In Example 29, the subject matter of any of Examples 27 or 28 can optionally further comprise that the polyatomic complex generation unit comprises an irradiation subunit configured to irradiate the silicon sample with particles.

[0091] In Example 30, the subject matter of Example 29 may optionally further comprise the particles comprising protons and / or electrons and / or neutrons and / or alpha particles.

[0092] In Example 31, the subject matter of any of Examples 27 to 30 can optionally further comprise that the polyatomic complex generation unit comprises an annealing subunit configured to anneal the silicon sample.

[0093] In Example 32, the subject matter of any of Examples 27 to 31 may optionally further comprise that the first determination unit comprises a spectrometer.

[0094] In Example 33, the subject matter of Example 32 can optionally further include the spectrometer being configured as an FTIR spectrometer.

[0095] In Example 34, the subject matter of any of Examples 32 or 33 can optionally further comprise the spectrometer being operable at a temperature in a range of about 4 K to about 20 K.

[0096] In Example 35, the subject matter of any of Examples 27 to 34 may optionally further comprise that the first determination unit is configured to irradiate the silicon sample with visible light during the determination of the quantity indicative of the content of the polyatomic complexes.

[0097] In Example 36, the subject matter of any of Examples 32 to 35 may optionally further comprise that the first determining unit is configured to determine at least one characteristic peak in a spectrum acquired by the spectrometer.

[0098] In Example 37, the subject matter of Example 36 may optionally further include that the first determining unit is configured to determine the height of the at least one characteristic peak and / or the area under the at least one characteristic peak as the quantity indicative of the content of the polyatomic complexes in the silicon sample.

[0099] In Example 38, the subject matter of Examples 36 and 37 may optionally further include that the first determination unit is configured to identify a plurality of characteristic peaks and to determine the quantity indicative of the content of the polyatomic complexes in the silicon sample as the sum of the areas under the plurality of characteristic peaks.

[0100] In Example 39, the subject matter of any of Examples 27 to 38 may optionally further comprise that the second determination unit is configured to determine the carbon content in the silicon sample using a calibration curve that assigns a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample.

[0101] In Example 40, the subject matter of Example 39 may optionally further include that the second determination unit is configured to select the calibration curve depending on the oxygen content in the silicon sample to be analyzed.

[0102] While the invention has been particularly shown and described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is accordingly indicated by the appended claims, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced.

Claims

[1] A method for determining the carbon content in a silicon sample (102), the method comprising: Generation of electrically active polyatomic complexes within the silicon sample (102), wherein the polyatomic complexes comprise at least one carbon atom, at least one oxygen atom and at least one hydrogen atom; Determining a quantity indicative of the content of the generated polyatomic complexes in the silicon sample (102); and Determining the carbon content in the silicon sample (102) from the determined quantity, wherein at least some of the polyatomic complexes are configured as flat donors. [2] The method of claim 1, wherein at least one polyatomic complex, several polyatomic complexes or most polyatomic complexes comprise / comprise several oxygen atoms. [3] Method according to one of claims 1 or 2, wherein the generation of the polyatomic complexes comprises rearrangement of carbon atoms from substitution lattice sites to interstitial lattice sites, wherein, if appropriate, the rearrangement is carried out by particle irradiation of the silicon sample (102), wherein the particles (112) optionally further comprise protons and / or electrons and / or neutrons and / or alpha particles. [4] Method according to one of claims 1 to 3, wherein generating the polyatomic complexes comprises annealing the silicon sample (102), wherein optionally the annealing is carried out at a temperature in a range of about 450°C to about 520°C, further optionally at a temperature of about 490°C. [5] The method of claim 4, wherein the annealing is carried out for a period of time in a range of about 30 minutes to about 7 hours, optionally for a period of time in a range of about 1 hour to about 5 hours. [6] A process according to any one of claims 1 to 5, wherein the polyatomic complexes have absorption peaks at 241 cm -1 and 247 cm -1 have. [7] Method according to one of claims 1 to 6, wherein the determination of the quantity indicative of the content of the polyatomic complexes in the silicon sample (102) is carried out by a spectroscopic method, where appropriate, the spectroscopic method comprises Fourier transform infrared spectroscopy (FTIR), wherein further optionally the Fourier transform infrared spectroscopy (FTIR) is carried out at a temperature in a range of about 4 K to about 20 K, further optionally at a temperature of about 10 K. [8] The method according to claim 7, wherein during the determination of the quantity indicative of the content of the polyatomic complexes, the silicon sample (102) is irradiated with visible light. [9] A method according to any one of claims 7 or 8, further comprising: Identifying at least one characteristic peak in a spectrum (128) obtained by the spectroscopic method. [10] The method of claim 9, wherein the quantity indicative of the content of the polyatomic complexes in the silicon sample (102) is determined as the height of the identified at least one characteristic peak and / or as the integrated area of ​​the identified at least one characteristic peak. [11] The method according to claim 9 and 10, wherein the spectroscopic method comprises identifying a plurality of characteristic peaks and the quantity indicative of the content of the polyatomic complexes in the silicon sample (102) is determined as the sum of the integrated areas of the plurality of characteristic peaks. [12] Method according to one of claims 1 to 11, wherein the determination of the carbon content in the silicon sample (102) is carried out using a calibration curve which assigns a unique carbon content to the determined quantity indicative of the content of the polyatomic complexes in the silicon sample (102). [13] Method according to claim 12, wherein the calibration curve is selected as a function of the oxygen content in the silicon sample (102) to be analyzed, wherein, if appropriate, the oxygen content in the silicon sample (102) to be analyzed is determined by Fourier transform infrared spectroscopy (FTIR), further if appropriate, the oxygen content is determined by Fourier transform infrared spectroscopy (FTIR), which is carried out at room temperature. [14] Method according to one of claims 1 to 13, wherein the silicon sample (102) is grown by the Czochralski method, optionally by the magnetic Czochralski method. [15] Measuring arrangement (100) for determining the carbon content in a silicon sample (102), the arrangement (100) comprising: a polyatomic complex generation unit (104) configured to generate electrically active polyatomic complexes within the silicon sample (102), the polyatomic complexes comprising at least one carbon atom, at least one oxygen atom, and at least one hydrogen atom; a first determination unit (106) configured to determine a quantity, which is indicative of the content of the generated polyatomic complexes in the silicon sample (102); and a second determination unit (108) configured to determine the carbon content in the silicon sample (102) from the determined quantity, wherein at least some of the polyatomic complexes are configured as flat donors. [16] Measuring arrangement (100) according to claim 15, wherein at least one polyatomic complex, several polyatomic complexes or most polyatomic complexes comprise / comprise several oxygen atoms. [17] Measuring arrangement (100) according to one of claims 15 or 16, wherein the polyatomic complex generation unit (104) comprises an irradiation subunit (111) configured to irradiate the silicon sample (102) with particles (112), wherein optionally the particles (112) comprise protons and / or electrons and / or neutrons and / or alpha particles. [18] The measuring arrangement (100) according to any one of claims 15 to 17, wherein the polyatomic complex generation unit (104) comprises an annealing subunit (116) configured to anneal the silicon sample (102). [19] Measuring arrangement (100) according to one of claims 15 to 18, wherein the first determination unit (106) comprises a spectrometer (118), which is optionally configured as an FTIR spectrometer. [20] The measuring arrangement (100) of claim 19, wherein the spectrometer (118) is operable at a temperature in a range of about 4 K to about 20 K. [21] Measuring arrangement (100) according to one of claims 15 to 20, wherein the first determination unit (106) is configured to irradiate the silicon sample (102) with visible light during the determination of the quantity indicative of the content of the polyatomic complexes. [22] Measuring arrangement (100) according to one of claims 19 to 21, wherein the first determination unit (106) is configured to determine at least one characteristic peak in a spectrum (128) which was acquired by means of the spectrometer (118). [23] The measuring arrangement (100) according to claim 22, wherein the first determination unit (106) is configured to determine the height of the at least one characteristic peak and / or the area under the at least one characteristic peak as the quantity indicative of the content of the polyatomic complexes in the silicon sample (102). [24] The measuring arrangement (100) according to claim 22 and 23, wherein the first determination unit (106) is configured to identify a plurality of characteristic peaks and to determine the quantity indicative of the content of the polyatomic complexes in the silicon sample (102) as the sum of the areas under the plurality of characteristic peaks. [25] Measuring arrangement (100) according to one of claims 15 to 24, wherein the second determination unit (108) is configured to determine the carbon content in the silicon sample (102) using a calibration curve which assigns a unique carbon content to the determined quantity which is indicative of the content of the polyatomic complexes in the silicon sample (102), wherein optionally the second determination unit (108) is configured to select the calibration curve as a function of the oxygen content in the silicon sample (102) which is to be analyzed.

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