JPH10154734A - Method for evaluating semiconductor crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method in which a crystal defect caused by interstitial oxygen and impurity oxygen contained in a semiconductor crystal surface layer part is simply evaluated with high sensitivity, and an evaluated sample can be recovered, relating to a total reflection attenuation spectral method. SOLUTION: A pretreatment for removal of a surface film such as an oxide film, etc., formed on the surface of a semiconductor crystal is performed, and then evaluation is performed in a total reflection attenuation spectral method. A difference spectrum (c) between evaluation spectrums (a) and (b) of a semiconductor crystal containing interstitial oxygen and a crystal defect and that containing little interstitial oxygen and crystal defect, respectively, is analyzed, thereby the interstitial oxygen and the crystal defect contained in the semiconductor crystal are evaluated. After etching and polishing of an arbitrary thickness in a depth direction from the surface of the semiconductor crystal are performed, a preprocessing wherein a surface film such as an oxide film, etc., formed on the surface of the semiconductor crystal is removed is performed for evaluation. After the semiconductor and IRE(internal reflection element) are set at a constant temperature in the range of 4.2-300K, evaluation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating semiconductor crystals by attenuated total reflection spectroscopy, and more particularly to an evaluation of impurity oxygen such as interstitial oxygen and crystal defects contained near the surface of a semiconductor crystal.

[0002]

2. Description of the Related Art As is well known, oxygen is extremely important as a crystal characteristic of silicon for LSI. Pull-up (CZ) crystals used in silicon devices such as VLSIs contain oxygen at or above the solid solubility limit. Oxygen in the crystal acts to strengthen the mechanical properties of the crystal. In addition, while oxygen precipitates generated by heat treatment have a bad effect on device characteristics, they also have the ability to getter contaminants such as heavy metals. It is.

Further, it has been found that the surface layer forming the element forms a denuded zone (DZ) having neither oxygen precipitation nor crystal defects due to outward diffusion from the surface and generation of internal minute defects. Therefore, evaluation of interstitial oxygen and impurity oxygen such as crystal defects contained in a semiconductor crystal, particularly evaluation of those in a crystal internal surface layer portion, has become an important factor in a semiconductor device process.

Conventionally, the evaluation of interstitial oxygen, crystal defects, and the like in a semiconductor crystal has been performed by infrared spectroscopy, secondary ion mass spectrometry, or the like.

[0005] Infrared spectroscopy is an analytical method for identifying and quantifying impurities in crystals from the position and intensity of an absorption band in an absorption spectrum in the infrared region. It is central.

[0006] In the secondary ion mass spectrometry, an element present in a sample is analyzed by irradiating the sample with oxygen, argon, or cesium ions and performing mass analysis of the secondary ions emitted from the sample. Is the way.

[0007]

The evaluation using the infrared spectroscopy is not an evaluation of the surface layer portion of the semiconductor crystal as a sample, but an evaluation based on average information of the entire crystal.
There is a problem that it is difficult to evaluate interstitial oxygen and crystal defects contained in the semiconductor crystal surface layer. In addition, this method generally requires a high-resistance sample to avoid absorption of free carriers in the infrared region.For example, in the case of a sample having a low resistance value, such as a high-concentration impurity-doped semiconductor crystal, a free-resistance sample is required. There is a problem that the absorption of the carrier itself is too strong to measure the absorption of the crystal itself.

FIG. 3 shows an evaluation result obtained by evaluating a semiconductor crystal D ′ having a resistance value of 0.01 Ωcm by a conventional method. FIG.
As shown in the figure, when the semiconductor crystal D ′ is irradiated with infrared light,
All infrared light is absorbed by free electrons contained in the semiconductor crystal E ′, and the infrared absorption spectrum cannot be measured.

In order to solve the above-mentioned problem, a sample body is formed by bonding a high-resistance semiconductor crystal containing almost no impurities such as interstitial oxygen and crystal defects to a low-resistance semiconductor crystal to form a sample. Absorption spectrum obtained by irradiating the sample with infrared light at a low temperature of 4.2K to 70K after polishing the semiconductor crystal thinly to several tens of microns,
Analyze and evaluate the difference spectrum calculated from the difference between the absorption spectrum obtained by irradiating infrared light only to the high-resistance semiconductor crystal containing almost no impurities such as interstitial oxygen and crystal defects. Attempts have been made to evaluate the concentration of oxygen such as interstitial oxygen contained in semiconductor crystals.

However, in this method, it is necessary to polish a low-resistance semiconductor crystal bonded to a high-resistance semiconductor crystal to make a sample in order to perform an evaluation, and it takes a very long time to process the sample. There is a problem. Further, since the sample used for evaluation cannot be reproduced, it is not very suitable for evaluation such as quality inspection.

The secondary ion mass spectrometry has the advantage of high sensitivity and the ability to perform analysis in the depth direction. However, the secondary ion mass spectrometry is an evaluation of the total oxygen in the crystal, and the interstitial contained in the surface layer of the semiconductor crystal is evaluated. There is a problem that the evaluation of oxygen and crystal defects alone cannot be performed alone.In addition, as described above, the semiconductor crystal to be inspected is subjected to evaluation after being cut into several tens of millimeters and sputtering the surface, so that There is a problem that the semiconductor crystal used is a non-reproducible destructive test.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In a method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, crystal defects caused by interstitial oxygen and impurity oxygen contained in a surface layer of a semiconductor crystal can be easily and easily reduced. It is an object of the present invention to provide a method for evaluating a semiconductor crystal which can be evaluated with high sensitivity and can regenerate an evaluation sample.

[0013]

According to a first aspect of the present invention, in a method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, a surface film such as an oxide film formed on the surface of the semiconductor crystal is removed. This is a method for evaluating a semiconductor crystal having a configuration in which pretreatment is performed, and then evaluation is performed by attenuated total reflection spectroscopy.

As described above, after the semiconductor crystal to be inspected is subjected to the pretreatment for removing the surface film of the semiconductor crystal, the absorption spectrum obtained by the attenuated total reflection spectroscopy is the same as that of the conventional semiconductor crystal. Since it is not affected by the strong absorption of the surface natural oxide film formed on the surface, the absorption spectrum absorbed by interstitial oxygen and crystal defects in the semiconductor crystal surface layer can be detected, and the interstitial in the semiconductor crystal surface layer can be detected. Oxygen and crystal defects can be evaluated.

Since it is not affected by the surface oxide film of the semiconductor crystal, the detection accuracy can be improved, and the interstitial oxygen and crystal defects in the surface layer of the semiconductor crystal having a low resistance value doped with a high concentration of impurities can be improved. Evaluation is also possible.

According to a second aspect of the present invention, there is provided the semiconductor device according to the first aspect, wherein the semiconductor crystal includes interstitial oxygen and crystal defects, and the semiconductor crystal includes substantially no interstitial oxygen and crystal defects. This is a method for evaluating a semiconductor crystal in which a difference spectrum between respective evaluation spectra of a crystal is analyzed to evaluate interstitial oxygen and crystal defects contained in the semiconductor crystal.

Even if the surface film of the semiconductor crystal to be inspected is removed, the absorption by the final end of the semiconductor crystal and the lattice vibration of the semiconductor crystal show strong absorption. For this reason, a semiconductor crystal having almost no interstitial oxygen and crystal defects on the crystal surface is used as a reference sample, the same processing is performed on the semiconductor crystal to be inspected, and the same evaluation test is performed. By evaluating the difference spectrum calculated from the spectrum and the absorption spectrum of the semiconductor crystal which is the reference sample, the lattice of the semiconductor crystal surface layer separated from the absorption due to the absorption at the edge of the semiconductor crystal and the absorption due to the lattice vibration, etc. The absorption spectrum due to the absorption of interstitial oxygen and crystal defects can be analyzed and evaluated.

According to a third aspect of the present invention, there is provided a method for evaluating a semiconductor crystal in which the same concentration of impurities is added to each of the semiconductor crystals according to the second aspect of the invention. .

According to the invention described in claim 3,
Since it is possible to perform measurement and evaluation of several microns from the surface of the semiconductor crystal without being affected by the lattice vibration of the semiconductor crystal or the like, it is possible to easily evaluate the surface of the semiconductor crystal even in a low-resistance semiconductor crystal. it can. However, even in the above evaluation method, the influence of the free electrons in the semiconductor crystal is not necessarily affected by the free electrons in the semiconductor crystal, and the influence of the free electrons increases in the low wavenumber region of the irradiated infrared light. When the impurity concentration increases, the absorption spectrum tends to be absorbed and curved as the baseline of the absorption spectrum becomes lower in the wavenumber range. If the baseline of the absorption spectrum of the semiconductor crystal changes, an error occurs in a difference spectrum calculated from the absorption spectrum of the semiconductor crystal of the reference sample, and the detection accuracy of semiconductor crystal evaluation decreases.

Therefore, when analyzing the semiconductor crystal to be inspected and the semiconductor crystal as a reference sample to which the same concentration of impurities is added, the effects of free electrons are almost the same. Since the baseline of the absorption spectrum of the reference sample also changes to the same extent, it is possible to calculate a difference spectrum without causing an error, and to evaluate the interstitial oxygen and crystal defects with high accuracy by analyzing the difference spectrum. Becomes possible.

According to a fourth aspect of the present invention, in a method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, the semiconductor crystal is etched and polished to an arbitrary thickness in a depth direction from the surface of the semiconductor crystal. This is a semiconductor crystal evaluation method in which a pretreatment for removing a surface film such as an oxide film formed on the surface is performed, and evaluation is performed by attenuated total reflection spectroscopy.

As described above, the semiconductor crystal to be inspected is etched and polished to an arbitrary thickness, so that not only the surface layer portion of the semiconductor crystal but also the inside can be locally evaluated.

According to a fifth aspect of the present invention, there is provided a method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, wherein the semiconductor crystal and the internal reflection element are set in a range from 4.2K to 30K.
This is a semiconductor crystal evaluation method in which evaluation is performed by attenuated total reflection spectroscopy after the temperature is set to a constant temperature in the range of 0K.

As described above, the semiconductor crystal and the internal reflection element (hereinafter referred to as “IRE”) are cooled at a low temperature from room temperature to 4.2 K, and the semiconductor crystal and the IRE are cooled. By doing so, a more sensitive evaluation can be performed. here,
4.2K indicates a temperature that can be cooled by liquid helium, and 300K indicates a general room temperature. In addition, as effects obtained by cooling the room temperature or lower, higher sensitivity evaluation can be performed by an increase in impurity absorption intensity and an effect of separating peaks, and an effect of suppressing lattice vibration of silicon.

According to the evaluation method of the present invention as described above, the interstitial oxygen and the crystal defects in the surface layer portion of the semiconductor crystal are reduced.
High-precision evaluation can be easily performed in a reproducible state. Then, it becomes possible to easily and accurately evaluate interstitial oxygen, crystal defects, and the like of a low-resistance semiconductor crystal containing a high-concentration impurity. In addition, it is possible to locally evaluate the semiconductor crystal as well as the interstitial oxygen and crystal defects in the surface layer of the semiconductor crystal.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific examples of the present invention will be described in detail in comparison with a conventional example.

First, a semiconductor crystal is subjected to attenuated total reflection spectroscopy (F
T-IR ATR: attenuated total reflection: Hereinafter, referred to as “FT-IR ATR method”. The following shows an example of the evaluation.

Here, the FT-IR ATR method is an evaluation method for performing analysis using an IRE having a high refractive index. In this method, a sample body is formed by bringing the IRE into contact with a semiconductor crystal to be inspected, and the total reflectance of the IRE is set to 1.
As 0, infrared light is incident on the sample at an arbitrary angle so as to be totally reflected at the interface between the IRE and the semiconductor crystal to be inspected. The sample is totally reflected if the semiconductor crystal to be inspected has no absorption, and the reflectance is 1.0. However, if the semiconductor crystal to be inspected has absorption, that is, a slight unevenness in the medium near the interface. If there is a property (such as the presence of an absorbing substance or various surface conditions), light is absorbed and the light is attenuated.
Occurs. This method evaluates the vicinity of the surface of the semiconductor crystal to be inspected by measuring the absorption spectrum of the reduced reflected light.

FIG. 4 shows a semiconductor crystal A ′ containing interstitial oxygen and crystal defects and a semiconductor crystal B ′ containing almost no interstitial oxygen and crystal defects as a reference sample of the semiconductor crystal A by FT-IR ATR. The results of the evaluation are shown. The semiconductor crystal A 'and the semiconductor crystal B' have not been subjected to the surface oxide film removal treatment.

FIG. 4A shows the relationship between the surface of the semiconductor crystal A ′ and the surface of the semiconductor crystal A ′.
FIG. 4B shows an absorption spectrum a ′ obtained by detecting a first sample body formed by contacting an RE with the semiconductor crystal B ′.
FIG. 9 shows an absorption spectrum b ′ obtained by detecting a second sample body formed by contacting the sample with the IRE. FIG. 4C shows a difference spectrum c ′ calculated from the spectrum a ′ and the spectrum b ′.

As shown in FIG. 4 (1) and FIG. 4 (2), strong absorption of the oxide system can be confirmed in both the spectrum a ′ and the spectrum b ′, and their spectrum patterns are similar. All the absorption peaks of the difference spectrum c ′ shown in FIG. 4 (3) are presumed to indicate absorption peaks relating to oxides, but clear absorption peaks due to interstitial oxygen and crystal defects cannot be confirmed. This is due to the strong absorption of the surface oxide film of the semiconductor crystal. Thus, it was confirmed that analysis and evaluation of interstitial oxygen, crystal defects, and the like contained in the surface layer of the semiconductor crystal cannot be performed by the conventional method.

Next, semiconductor crystals were evaluated according to the present invention.

FIG. 1 is a diagram showing evaluation results of a semiconductor crystal in a specific example of the present invention.

In this example, semiconductor crystals were analyzed by the FT-IR ATR method. First, a surface oxide film of a semiconductor crystal including interstitial oxygen and crystal defects is removed by HF to obtain a semiconductor crystal A to be inspected, and at the same time, the surface of the semiconductor crystal substantially free of interstitial oxygen and crystal defects and the like. The oxide film was removed by HF to obtain a semiconductor crystal B as a reference sample of the semiconductor crystal A. The semiconductor crystal A
The first sample body is formed by contacting the surface of the semiconductor crystal B with the IRE which is a medium having a high refractive index.
The second sample body was formed by contacting the RE. Thereafter, the first and second sample bodies were irradiated with infrared light, and the obtained spectra were analyzed. Hereinafter, the results are shown in FIG.

FIG. 1A shows an absorption spectrum a as a detection result of the first sample body, and FIG. 1B shows an absorption spectrum b as a detection result of the second sample body. Comparing the absorption spectrum a and the absorption spectrum b, it can be confirmed that the absorption spectrum a has a peak α different from the spectrum b near the wave number of 1107 cm ^-1 . This peak α indicates absorption by interstitial oxygen contained in the surface layer portion of the semiconductor crystal A. However, since the absorption spectrum a overlaps with the absorption due to lattice vibration and other causes, it is desirable to separate the absorption due to these lattice vibrations and other causes to analyze interstitial oxygen and crystal defects.

Then, the difference spectrum c is calculated from the absorption spectrum a and the absorption spectrum b to separate the absorption due to the lattice vibration and other causes, and the analysis and evaluation of only the interstitial oxygen and the crystal defects of the semiconductor crystal A are performed. It becomes possible.

FIG. 1 (3) is a diagram corresponding to FIGS. 1 (1) and 1 (2).
2 shows a difference spectrum c between the spectrum a and the spectrum b shown in FIG. As shown in FIG. 1C, the spectrum c has a clear peak γ at a wavenumber of 1107 cm ⁻¹ , and this peak γ is considered to be absorption by interstitial oxygen in the semiconductor crystal A. By analyzing the peak γ, interstitial oxygen and crystal defects can be analyzed and evaluated.

As described above, since the surface oxide film of the semiconductor crystal is subjected to the evaluation test after the removal treatment, the interstitial oxygen and the crystal defects in the semiconductor crystal surface layer are not affected by the strong absorption of the surface oxide film. In addition, a semiconductor oxide having almost no interstitial oxygen and crystal defects on the crystal surface is used as a reference sample, and a surface oxide film is similarly removed to obtain a semiconductor crystal to be inspected. The absorption spectrum, by performing the analysis and evaluation of the difference spectrum calculated from the absorption spectrum obtained from the semiconductor crystal as the reference sample, due to the absorption and lattice vibration of the edge of the semiconductor crystal contained in the detected absorption spectrum The interstitial oxygen and crystal defects contained in the semiconductor crystal surface layer can be evaluated with high accuracy without being affected by absorption due to other causes such as absorption.

As the semiconductor crystal having almost no interstitial oxygen and crystal defects in the crystal surface layer serving as the reference sample, for example, an EP semiconductor crystal or an FZ semiconductor crystal can be used. The surface oxide film is made of HF, BHF, NH
₄ OH, NaOH, KOH, HClgas etching,
The removal treatment can be performed by a hydrogen heat treatment or the like.

Next, the results of an evaluation test of a semiconductor crystal containing a high-concentration impurity by the evaluation method of this embodiment will be described.

FIG. 2 shows a result of evaluation of a semiconductor crystal containing a high concentration impurity, that is, a semiconductor crystal having a low resistance in a specific example of the present invention. Also in this example, the semiconductor crystal was evaluated using the FT-IR ATR method as in the previous example. The infrared absorption spectrum data shown in FIG. 2 shows a spectrum d detected from a semiconductor crystal D having a resistance of 0.01 Ωcm and a spectrum e detected from a semiconductor crystal E having a resistance of 10 Ωcm. The semiconductor crystal D and the semiconductor crystal E are subjected to a surface oxide film removal treatment in advance similarly to the previous example, and each of them is brought into contact with the IRE to form a sample body and is subjected to an evaluation test.

As described above, according to the method of the present invention, not only the semiconductor crystal having a high resistance value but also the semiconductor crystal having a low resistance value containing a high-concentration impurity, which has conventionally been difficult to measure, A peak due to absorption of interstitial oxygen and crystal defects of the crystal can be detected, and by analyzing the detected peak, it is possible to evaluate interstitial oxygen and crystal defects contained in the low-resistance semiconductor crystal surface layer portion. It becomes possible.

As shown in FIG. 2, the spectrum d obtained from the semiconductor crystal D having a low resistance value is lower than the spectrum e obtained from the semiconductor crystal E having a high resistance value. The base line is curved. This is due to the influence of free electrons inside the semiconductor crystal D. When the baseline of a spectrum detected from a semiconductor crystal having a low resistance value changes, the difference spectrum calculated from the absorption spectrum of the semiconductor crystal having a low resistance and the absorption spectrum of the semiconductor crystal serving as a reference sample is changed. An error occurs and the evaluation accuracy decreases. In this case, for example, using a reference sample doped with the same concentration of impurities as the semiconductor crystal D having the low resistance value, the difference between the absorption spectrum of the reference sample and the absorption spectrum d of the low resistance semiconductor crystal D is used. What is necessary is just to calculate a spectrum. When a semiconductor crystal to which an impurity having the same concentration as that of the impurity contained in the low-resistance semiconductor crystal is added is used as a reference sample, the absorption spectrum of the reference sample similarly curves in the low wavenumber region, so that the low-resistance No error occurs in the difference spectrum calculated from the absorption spectrum of the semiconductor crystal of the above and the absorption spectrum of the semiconductor crystal as the reference sample.

As described above, by using a semiconductor crystal containing the same concentration of impurities as a low-resistance semiconductor crystal as a reference sample, even a low-resistance semiconductor crystal can be evaluated with high accuracy without being affected by high-concentration impurities. It can be performed.

Further, the semiconductor crystal to be inspected after the surface oxide film is removed is further etched and polished to an arbitrary thickness and evaluated by the above-described method. It is also possible to perform a comprehensive evaluation.

When performing the evaluation method of the present invention,
When the semiconductor crystal to be inspected, the semiconductor crystal to be a reference sample, the IRE, and the like are cooled to room temperature or lower to 4.2 K and the above evaluation is performed, a clearer peak can be detected, and a more accurate evaluation can be performed. It can be carried out.

[0047]

As described above, according to the semiconductor crystal evaluation method of the present invention, the semiconductor crystal to be inspected is subjected to the FT-IR ATR after the pretreatment for removing the surface film of the semiconductor crystal. In order to evaluate the method, it is possible to detect the absorption spectrum absorbed by interstitial oxygen and crystal defects in the surface layer of the semiconductor crystal without being affected by the strong absorption of the surface film formed on the surface of the semiconductor crystal. The evaluation of interstitial oxygen and crystal defects in the crystal surface layer can be performed with high accuracy.

Even if the surface film of the semiconductor crystal to be inspected is removed, the absorption by the last end of the semiconductor crystal and the lattice vibration of the semiconductor crystal show strong absorption. It is difficult to accurately evaluate only interstitial oxygen and crystal defects in the surface layer.

In the present invention, a semiconductor crystal to be inspected is subjected to a pretreatment for removing a surface film in consideration of the influence of infrared light absorption such as lattice vibration, and a semiconductor to be a reference sample is also subjected to the pretreatment. Similarly, a first sample in which a pretreatment for removing the surface film is performed and the surface of the semiconductor crystal to be inspected is brought into contact with the IRE, and a second sample in which the surface of the reference target semiconductor crystal is brought into contact with the IRE. By irradiating the sample body with infrared light and analyzing the difference spectrum calculated from the first absorption spectrum and the second absorption spectrum detected from the first and second sample bodies, respectively, Interstitial oxygen and crystal defects contained in the surface layer of the semiconductor crystal can be evaluated with high accuracy without being affected by the surface state of the crystal.

When a semiconductor crystal containing a high-concentration impurity is detected, the base line of an absorption spectrum is curved toward a lower wavenumber region due to the influence of free electrons of the semiconductor crystal, and the semiconductor crystal containing a high-concentration impurity is removed. There is a problem that an error occurs between the detected absorption spectrum and the difference spectrum calculated from the absorption spectrum detected from the semiconductor crystal as the reference sample.

In this case, by adding an impurity having the same concentration as that of the semiconductor crystal containing the high-concentration impurity to the semiconductor crystal serving as the reference sample and performing the main evaluation, the error of the difference spectrum is eliminated, and the accuracy of the accuracy is improved. Good detection can be performed.

The semiconductor crystal having been subjected to the surface oxide film removal treatment is etched and polished to an arbitrary thickness to obtain a semiconductor crystal.
When a sample is formed by being brought into contact with the RE, and the sample is evaluated, it is possible to locally evaluate not only the surface layer of the semiconductor crystal but also the inside.

Further, the semiconductor crystal forming the sample body and I
RE to a constant temperature in the range of 4.2K to 300K,
Further, when the evaluation is performed after the sample body is cooled at a low temperature, more accurate and highly sensitive evaluation can be performed.

As described above, according to the evaluation method of the present invention, the interstitial oxygen and crystal defects in the surface layer portion of the semiconductor crystal are reduced.
Evaluation can be easily performed with high accuracy in a reproducible state. Then, it becomes possible to easily and accurately evaluate interstitial oxygen, crystal defects, and the like of a low-resistance semiconductor crystal containing a high-concentration impurity. In addition, it is possible to locally evaluate the semiconductor crystal as well as the interstitial oxygen and crystal defects in the surface layer of the semiconductor crystal.

[Brief description of the drawings]

FIG. 1 relates to a specific example of the present invention, wherein (1) shows an absorption spectrum of a semiconductor crystal to be inspected, and (2)
Indicates an absorption spectrum obtained by detecting a semiconductor crystal serving as a reference sample, and (3) indicates a difference spectrum calculated from the absorption spectrum shown in (1) and the absorption spectrum shown in (2).

FIG. 2 relates to a specific example of the present invention, and has a resistance value of 0.01Ω.
The absorption spectrum which detected the semiconductor crystal of cm cm and the absorption spectrum which detected the semiconductor crystal of resistance value 10 (ohm) cm are shown.

FIG. 3 shows an absorption spectrum obtained by detecting a semiconductor crystal having a resistance value of 0.01 Ωcm according to a conventional example.

FIG. 4 shows an absorption spectrum of a semiconductor crystal to be inspected, (2) shows an absorption spectrum of a semiconductor crystal to be a reference sample, and (3) shows an absorption spectrum of (1). 2 shows a difference spectrum calculated from the absorption spectrum shown and the absorption spectrum shown in (2).

[Explanation of symbols]

 A semiconductor crystal A 'semiconductor crystal B semiconductor crystal B' semiconductor crystal C semiconductor crystal C 'semiconductor crystal D semiconductor crystal D' semiconductor crystal E semiconductor crystal a absorption spectrum a 'absorption spectrum b absorption spectrum b' absorption spectrum c absorption spectrum c ' Absorption spectrum d Absorption spectrum e Absorption spectrum α peak γ peak

Claims (5)

[Claims] In a method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, a pretreatment for removing a surface film such as an oxide film formed on a surface of a semiconductor crystal is performed, and then an evaluation by attenuated total reflection spectroscopy is performed. A method for evaluating a semiconductor crystal. 2. Analyzing a difference spectrum between respective evaluation spectra of a semiconductor crystal containing interstitial oxygen and crystal defects and a semiconductor crystal containing almost no interstitial oxygen and crystal defects, and 2. The method for evaluating a semiconductor crystal according to claim 1, wherein the evaluation is performed on interstitial oxygen and crystal defects contained. 3. The method for evaluating a semiconductor crystal according to claim 2, wherein the same concentration of impurities is added to each of said semiconductor crystals. 4. A method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, comprising the steps of: etching and polishing an arbitrary thickness in a depth direction from the surface of the semiconductor crystal; A method for evaluating a semiconductor crystal, comprising performing pretreatment for removing a film and performing evaluation by attenuated total reflection spectroscopy. 5. A method for evaluating a semiconductor crystal by attenuated total reflection spectroscopy, wherein the semiconductor crystal and the internal reflection element are in the range of 4.2K to 3K.
A method for evaluating a semiconductor crystal, comprising: performing evaluation by attenuated total reflection spectroscopy after a constant temperature in a range of 00K.