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CN-121978062-A - Method and device for detecting metal ion content in semiconductor material

CN121978062ACN 121978062 ACN121978062 ACN 121978062ACN-121978062-A

Abstract

The invention provides a method and a device for detecting metal ion content in a semiconductor material, wherein under the condition of fixing incident laser parameters, the method firstly tests the reflectivity of a zero magnetic field and a plurality of samples to be detected under different magnetic field intensities on incident laser to obtain a first data set with the reflectivity changing along with the magnetic field, then fits to obtain a first curve with the reflectivity changing along with the magnetic field to obtain a first diffusion length, then heats the sample to be detected to enable the metal ions to be in a free state, cools the sample to be detected, then again conducts reflectivity test in the same manner to obtain a second data set, fits to obtain a second curve to obtain a second diffusion length, and finally obtains the content of the metal ions according to a formula. The detection device comprises a sample stage, a magnetic field applying device and an optical path component. The invention uses magnetic field-optics cooperative modulation, and can realize high-sensitivity and nondestructive detection of the concentration and distribution of metal impurities in the semiconductor material.

Inventors

  • LI ZONGXIN

Assignees

  • 芯恩（青岛）集成电路有限公司

Dates

Publication Date
20260505
Application Date
20260302

Claims (10)

  1. 1. The method for detecting the metal ion content in the semiconductor material is characterized by comprising the following steps of: Providing a sample to be detected, wherein the sample to be detected comprises a doped semiconductor layer, and metal ions are arranged in the doped semiconductor layer; Fixing parameters of incident laser, testing the reflectivity of a sample to be tested on the incident laser under the conditions of a zero magnetic field and a plurality of different magnetic field intensities, taking the reflectivity corresponding to the zero magnetic field as a reflectivity reference value, calculating the change rate of the reflectivity corresponding to the plurality of different magnetic field intensities relative to the reflectivity reference value to obtain a first data set with the change rate of the reflectivity along with the change of the magnetic field, fitting according to the first data set to obtain a first curve with the change rate of the reflectivity along with the change of the magnetic field, and calculating a first diffusion length L 1 based on the first curve; heating the sample to be detected to a first preset temperature so that the metal ions are in a free state, and then cooling the sample to be detected to a second preset temperature; Testing the reflectivity of the sample to be tested to the incident laser under the conditions of zero magnetic field and a plurality of different magnetic field intensities to obtain a second data set with the reflectivity changing along with the magnetic field, fitting according to the second data set to obtain a second curve with the reflectivity changing along with the magnetic field, and calculating a second diffusion length L 2 based on the second curve; According to the formula Solving the content of the metal ions, wherein A is the code number of the metal ions, C is a constant term for the content of the metal ion.
  2. 2. The method for detecting metal ion content in semiconductor material according to claim 1, wherein when the first curve and the second curve are obtained by fitting, both the first curve and the second curve are fitted to a theoretical model Where ΔR is the reflectance change, B is the magnetic field strength, oc is the proportional sign, and L D is the diffusion length.
  3. 3. The method of claim 1, wherein the doped semiconductor layer comprises a silicon layer, and the corresponding constant term C is 1.05E16.
  4. 4. The method of claim 1, wherein the doping element in the doped semiconductor layer comprises boron.
  5. 5. The method for detecting metal ion content in semiconductor material according to claim 1, wherein the metal ion comprises one or more of Fe ion, cr ion, cu ion and Ni ion.
  6. 6. The method of claim 1, wherein the applied magnetic field strength is sequentially increased by no more than 0.2T during the acquisition of the first data set and the second data set, and/or the applied magnetic field strength is sequentially increased by no more than 2 during the acquisition of the first data set and the second data set within a range of 0T to N T.
  7. 7. The method for detecting metal ion content in semiconductor material according to claim 1, wherein the first preset temperature is 200-400 ℃ and the second preset temperature is 22-24 ℃.
  8. 8. A detection apparatus for performing the method for detecting the metal ion content in a semiconductor material according to any one of claims 1 to 7, comprising: The sample stage is used for bearing a sample to be detected and has heating and cooling functions; the magnetic field applying device is arranged above the sample table; The optical path component is arranged between the sample table and the magnetic field applying device, the optical path component comprises a laser, a polarizer, a focusing lens, a spectroscope, a reflecting mirror and a photoelectric detector which are sequentially arranged according to a preset path, laser emitted by the laser sequentially passes through the polarizer and the focusing lens to reach the spectroscope, then is reflected to the surface of a sample to be detected through the spectroscope, then reaches the spectroscope again after being reflected by the sample to be detected, and is transmitted to the reflecting mirror through the spectroscope, and the photoelectric detector receives the laser reflected by the reflecting mirror and performs photoelectric conversion to obtain reflectivity data.
  9. 9. The apparatus of claim 8, wherein the sample stage comprises a non-magnetic ceramic base.
  10. 10. The apparatus of claim 8, wherein the laser emits laser light at 830 nm wavelength and/or the polarizer has an extinction ratio >1000:1, and the beam splitter has a reflectance/transmittance of 1:1.

Description

Method and device for detecting metal ion content in semiconductor material Technical Field The invention belongs to the technical field of semiconductors, and relates to a method and a device for detecting the content of metal ions in a semiconductor material. Background In the semiconductor industry, metal impurities such as iron, chromium and the like can introduce deep level defects in forbidden bands, become a recombination center of electron-hole pairs, remarkably shorten the service life of minority carriers and influence the efficiency of semiconductor components. For example, in the production of silicon, both the growth of silicon and the film formation of oxide are prevented from contamination with Fe, which has an important influence on the quality of the product. Traditional detection methods such as Secondary Ion Mass Spectrometry (SIMS) and Deep Level Transient Spectra (DLTS) have high precision, but have the problems of (1) destructiveness that sample pretreatment (such as etching and electrode preparation) is required, and (2) high cost and long detection period. Therefore, how to provide a method and a device for detecting the content of metal ions in a semiconductor material, so as to detect the concentration and distribution of impurities in the semiconductor material with high sensitivity and non-destructiveness, is an important technical problem to be solved by those skilled in the art. It should be noted that the foregoing description of the background art is only for the purpose of providing a clear and complete description of the technical solution of the present application and is presented for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background of the application section. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method and an apparatus for detecting metal ion content in semiconductor materials, which are used for solving the problems of high destructiveness and high cost of the detection method in the prior art. To achieve the above and other related objects, the present invention provides a method for detecting metal ion content in a semiconductor material, comprising the steps of: Providing a sample to be detected, wherein the sample to be detected comprises a doped semiconductor layer, and metal ions are arranged in the doped semiconductor layer; Fixing parameters of incident laser, testing the reflectivity of a sample to be tested on the incident laser under a zero magnetic field and a plurality of different magnetic field intensities, taking the reflectivity corresponding to the zero magnetic field as a reflectivity reference value, calculating the change rate of the reflectivity corresponding to the plurality of different magnetic field intensities relative to the reflectivity reference value to obtain a first data set with the change rate of the reflectivity along with the change of the magnetic field, fitting according to the first data set to obtain a first curve with the change rate of the reflectivity along with the change of the magnetic field, and calculating a first diffusion length L1 based on the first curve; heating the sample to be detected to a first preset temperature so that the metal ions are in a free state, and then cooling the sample to be detected to a second preset temperature; testing the reflectivity of the sample to be tested to the incident laser under the conditions of zero magnetic field and a plurality of different magnetic field intensities to obtain a second data set with the reflectivity changing along with the magnetic field, fitting according to the second data set to obtain a second curve with the reflectivity changing along with the magnetic field, and calculating a second diffusion length L2 based on the second curve; According to the formula Solving the content of the metal ions, wherein A is the code number of the metal ions,C is a constant term for the content of the metal ion. Optionally, when the first curve and the second curve are obtained by fitting, fitting both the first curve and the second curve to a theoretical modelWhere ΔR is the reflectance change, B is the magnetic field strength, oc is the proportional sign, and L D is the diffusion length. Optionally, the doped semiconductor layer includes a silicon layer, and the corresponding constant term C is labeled 1.05E16. Optionally, the doping element in the doped semiconductor layer includes boron. Optionally, the metal ions include one or more of Fe ions, cr ions, cu ions, and Ni ions. Optionally, during the process of acquiring the first data set and the second data set, the applied magnetic field strength is sequentially increased, and the increasing amplitude is not more than 0.2T. Optionally, in the process of acquiring the firs