Test method for substitutional atomic carbon content of silicon by infrared absorption
1 Scope
This standard specifies the test method for substitutional atomic carbon content of silicon by infrared absorption.
This standard is applicable to the determination of substitutional atomic carbon content in p-type wafers with a resistivity of greater than 3Ω·cm and n-type wafers with a resistivity of greater than 1Ω·cm. For wafers with low precision requirements, this method may be used to measure the substitutional atomic carbon content in wafers with a resistivity of greater than 0.1Ω·cm. Since carbon may also exist in the interstitial position, this method cannot be used to determine the total carbon content.
This standard is also applicable to the determination of substitutional atomic carbon content in silicon polycrystalline, but carbon in the grain boundary area cannot be determined.
The effective range of atomic carbon content measured in this standard is from the substitutional atomic carbon content of silicon of 5×1015at·cm-3 (0.1ppma) to the maximum solubility of atomic carbon at room temperature, with the lower detection limit at 77K of 5×1014at·cm-3 (0.01ppma).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the referenced document applies.
GB/T 6618 Test method for thickness and total thickness variation of silicon slices
GB/T 14264 Semiconductor materials -Terms and definitions
3 Terms and definitions
For the purposes of this standard, the terms and definitions given in GB/T 14264 as well as the following apply.
3.1
background spectrum
spectral lines in infrared spectrometer obtained by single beam measurement in the absence of samples, usually including nitrogen, air and other information
3.2
baseline
a tangent line made from the minimum absorbance on both sides of the carbon peak in the measurement pattern, which is used to calculate the absorption coefficient α, as shown in Figure 1
3.3
baseline absorbance
baseline value at the wave number corresponding to the carbon peak for calculating absorption peak height
3.4
Fourier transform infrared (FTIR) spectrometer
an infrared spectrometer that acquires data by converting an interferogram obtained by an interferometer into an amplitude-wavenumber (or wavelength) spectrogram by Fourier transform
3.5
full width at half maximum (FWHM)
width of absorption band at half peak height, as shown in Figure 1
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Interference factors
6 Measuring apparatus
7 Sample preparation
8 Operation procedures
9 Calculation of measuring result
10 Precision
11 Report
