A non-destructive determination method for the conductivity type of silicon carbide crystal

Abstract

The invention relates to a non-destructive determination method of the conductivity type of a silicon carbide crystal. The method comprises the steps that an ultraviolet-visible-near-infrared spectrophotometer is used to measure the spectrum transmittance of a SiC sample to be measured; the incidence direction of probe light is along the c-axis direction of a SiC wafer; the measurement index is absorbance; according to the formula alpha={A+2log10(1-R)} / (d / ln10)(1), the absorption coefficient curve of the silicon carbide sample is calculated, wherein the absorption coefficient of the curve changes with the wavelength; the ultraviolet absorption edge position Eg is acquired from the curve; and a semi-insulating type ultraviolet absorption edge position determination symbol is compared with the absorption edge position Eg to acquire the conductivity type of the semi-insulating wafer. The method has the advantages that based on a spectral analysis method, the conductive type of the high-purity semi-insulating silicon carbide wafer is detected and sieved; the sample to be measured is not damaged; the detection process is easy for automation and program control; an outgoing product can be comprehensively inspected; and the method can be used for product inspection of complete wafers of 2, 3, 4 and 6 inches in the current market.

Description

technical field [0001] The invention relates to a performance testing technology of a semiconductor single crystal, in particular to a method for non-destructive determination of the conductivity type of a silicon carbide crystal. Background technique [0002] Silicon carbide is a typical wide-bandgap semiconductor material and the third-generation semiconductor material after silicon and gallium arsenide. Compared with silicon and gallium arsenide, silicon carbide materials have excellent properties such as high thermal conductivity, high breakdown field strength, and high saturation electron drift rate, and have great application prospects in high temperature, high frequency, high power, and radiation-resistant devices . Transistors made of semi-insulating silicon carbide can generate power five times the power density of GaAs microwave devices at frequencies up to 10 GHz. Therefore, semi-insulating silicon carbide single crystal is currently the best substrate material ...

AI Technical Summary

Problems solved by technology

Using the non-contact resistivity tester (COREMA) commonly used in the industry, although it is a non-destructive testing method, only the resistivity of the silicon carbide wafer can be obtained but the conductivity type cannot be obtained.

It is known that the conductivity type of SiC wafers can be determined by secondary ion mass spectrometer or Hall test system, but the above two test methods are destructive tests, which can only be used for sampling testing, and cannot be used for all products in the industrial production process. To evaluate and identify

Moreover, the Hall system has no ability to judge ultra-high resistance silicon carbide substrates (resistivity greater than 1E11 ohm cm)

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