SiC wafer defect measuring method, reference sample, and method of manufacturing SiC epitaxial wafer
A SiC wafer defect measuring method which includes a device management step of managing a defect measuring device by irradiating a reference sample made of a material having a light-emitting intensity that does not change with repeated irradiation by excitation light and which has a pattern made of recesses and/or protrusions in the surface, the irradiation by the excitation light being performed before measuring defects in a SiC wafer and under the same irradiation conditions as the measurement of the defects in the SiC wafer, and then measuring the S/N ratio of the pattern from a reflection image of the pattern.
1. A SiC wafer defect measuring method of measuring defects in a SiC wafer using a photoluminescence device, the method comprising:
a device management step of managing a defect measuring device by irradiating a reference sample which is made of a material having a light-emitting intensity that does not change with repeated irradiation by excitation light and which has a pattern made of recesses and/or protrusions in a surface thereof, the irradiation by the excitation light being performed before measuring defects in a SiC wafer and under the same irradiation conditions as the measurement of the defects in the SiC wafer, and then measuring a S/N ratio of the pattern from a reflection image of the pattern.
2. The SiC wafer defect measuring method according to claim 1 , wherein a plurality of the patterns are formed in the reference sample.
3. The SiC wafer defect measuring method according to claim 2 , wherein a number density of patterns formed in the reference sample is from 0.1 to 1000 patterns/cm 2 .
4. The SiC wafer defect measuring method according to claim 2 , wherein a number of patterns is measured from a reflection image of the pattern by using a S/N ratio of the reflection image.
5. The SiC wafer defect measuring method according to claim 2 , wherein a number of patterns is measured automatically from a reflection image of the pattern.
6. The SiC wafer defect measuring method according to claim 1 , wherein the pattern includes a plurality of element patterns made of recesses and/or protrusions in a surface of the material.
7. The SiC wafer defect measuring method according to claim 6 , wherein an aspect ratio between a depth and a length of a long side of the element pattern is at least 0.04.
8. The SiC wafer defect measuring method according to claim 6 , wherein the element pattern has a rectangular shape.
9. The SiC wafer defect measuring method according to claim 6 , wherein a length of a long side of the element pattern is 100 μm or less.
10. The SiC wafer defect measuring method according to claim 1 , wherein a length of a short side of a pattern formed in the reference sample is from 5 to 50 μm in the reflection image, and a length of a long side is at least 10 μm.
11. A reference sample used in a method of measuring defects in a SiC wafer using a photoluminescence device,
wherein the reference sample is made of a material having a light-emitting intensity that does not change with repeated irradiation by excitation light, and has a pattern made of recesses and/or protrusions in a surface thereof,
wherein the pattern includes a plurality of element patterns made of recesses and/or protrusions in a surface of the material, and
wherein an aspect ratio between a depth and a length of a long side of the element pattern is at least 0.04.
12. The reference sample according to claim 11 , wherein a plurality of the patterns are formed.
13. A method of manufacturing a SiC epitaxial wafer, the method comprising:
a device management step of managing a defect measuring device by irradiating a reference sample which is made of a material having a light-emitting intensity that does not change with repeated irradiation by excitation light and which has a plurality of patterns made of recesses and/or protrusions in a surface thereof, the irradiation by the excitation light being performed before measuring defects in a SiC wafer and under the same irradiation conditions as the measurement of the defects in the SiC wafer, and then measuring a S/N ratio of the pattern from a reflection image of the pattern.