Defect classification equipment for silicon carbide substrate using single incident light-based photoluminescence and defect classification method using the same

Abstract

Stack fault inspection apparatus and method are disclosed. The apparatus includes a sample stage fixing the silicon carbide substrate and allow the incident light to scan the substrate surface; an incident light source configured to irradiate a vertical illumination light of a wavelength corresponding to an energy greater than a band gap energy of the substrate to at least a portion of a surface of the substrate in a direction substantially perpendicular to the surface of the substrate; a photomultiplier tube (PMT) configured to obtain a photoluminescence mapping image having a wavelength corresponding to the band gap energy of the substrate from the surface of the substrate; and a controller configured to process the mapping image and identify stacking faults.

What is claimed is: 
     
         1 . A method of inspecting a stacking fault of a silicon carbide substrate using single incident light-based photoluminescence, the method comprising:
 irradiating a vertical illumination light of a wavelength corresponding to an energy greater than a band gap energy of the substrate to at least a portion of a surface of the substrate, in a direction substantially perpendicular to the surface of the substrate;   obtaining a photoluminescence mapping image having a wavelength corresponding to the band gap energy of the substrate from the surface of the substrate using a photomultiplier tube (PMT);   classifying identifiable defects having different wavelengths from the mapping image having the wavelength corresponding to the band gap energy of the substrate obtained from the PMT into shapes and sizes and securing location data of the identifiable defects;   classifying stacking faults from the classified defects and assigning coordinates to each central position of the stacking faults using the location data;   sequentially irradiating the vertical illumination light for the stacking faults to which the coordinates are assigned;   acquiring a photoluminescence spectrum emitted from each stacking fault to which the vertical illumination light is irradiated with a spectrometer; and   comparing a peak wavelength in a region of 400 nm or more of the photoluminescence spectrum obtained from each stacking fault with a central wavelength in stacking fault database to classify characteristics of each stacking fault.   
     
     
         2 . The method of  claim 1 ,
 wherein classifying the stacking faults from the classified defects comprises comparing the defects classified by shape and size with the stacking fault database comprising shapes and sizes of stacking faults of 1SSF, 2SSF, 3SSF, 4SSF and 3C.   
     
     
         3 . The method of  claim 1 ,
 wherein the wavelength corresponding to the band gap energy of the substrate is 390 nm, and the wavelength of the vertical illumination light is 355 nm.   
     
     
         4 . The method of  claim 1 ,
 wherein the center wavelengths of 1SSF, 2SSF, 3SSF, 4SSF and 3C of the stacking fault database are 420 nm, 500 nm, 480 nm, 455 nm and 540 nm, respectively, and   wherein in the range of 400 nm or more of the photoluminescence spectrum, the peak wavelength 5 nm above and below the center wavelength of each stacking fault database is classified as a stacking fault.   
     
     
         5 . An apparatus for inspecting a stacking fault of a silicon carbide substrate using single incident light-based photoluminescence, the apparatus comprising:
 a sample stage configured to fix the silicon carbide substrate and allow the incident light to scan the substrate surface;   an incident light source configured to irradiate a vertical illumination light of a wavelength corresponding to an energy greater than a band gap energy of the substrate to at least a portion of a surface of the substrate in a direction substantially perpendicular to the surface of the substrate;   a photomultiplier tube (PMT) configured to obtain a photoluminescence mapping image having a wavelength corresponding to the band gap energy of the substrate from the surface of the substrate;   at least one controller configured to:
 classify identifiable defects displayed on the photoluminescence mapping image of the substrate obtained from the PMT into shapes and sizes and secure position data, 
 classify stacking faults from the classified defects and assigning coordinates to the respective central positions of the stacking faults using position data, and 
 adjust the stage and the incident light source to sequentially irradiate the vertical illumination light to the coordinate assigned to each of the stacking faults; 
   a spectrometer configured to obtain a photoluminescence spectrum emitted from each stacking fault to which the vertical illumination light is irradiated; and   the at least one controller configured to compare a peak wavelength in a region of 400 nm or more of the photoluminescence spectrum obtained from each stacking fault with a central wavelength in the stacking fault database classify characteristics for each stacking fault.   
     
     
         6 . The apparatus of  claim 5 ,
 wherein when the at least one controller classifies the stacking faults from the classified defects, the at least one controller is further configured to compare the identifiable defects classified by shape and size with the stacking fault database comprising shapes and sizes of stacking faults of 1SSF, 2SSF, 3SSF, 4SSF and 3C.   
     
     
         7 . The apparatus of  claim 5 ,
 the wavelength corresponding to the band gap energy of the substrate is 390 nm, and the wavelength of vertical illumination light having a wavelength corresponding to energy greater than the band gap energy of the substrate is 355 nm.   
     
     
         8 . The apparatus of  claim 5 ,
 wherein the center wavelengths of 1SSF, 2SSF, 3SSF, 4SSF and 3C of the stacking fault database are 420 nm, 500 nm, 480 nm, 455 nm and 540 nm respectively, and   wherein, in the range of 400 nm or more of the photoluminescence spectrum, the peak wavelength is between 5 nm above and below the center wavelength of each stacking fault database is to be classified as a corresponding stacking fault.   
     
     
         9 . A non-transitory computer-readable storage medium storing at least one instruction therein, wherein the at least one instruction, when executed by a processor of an inspection apparatus, causes the processor to perform a method of inspecting a stacking fault of a silicon carbide substrate using single incident light-based photoluminescence, the method comprising:
 irradiating a vertical illumination light of a wavelength corresponding to an energy greater than a band gap energy of the substrate to at least a portion of a surface of the substrate, in a direction substantially perpendicular to the surface of the substrate;   obtaining a photoluminescence mapping image having a wavelength corresponding to the band gap energy of the substrate from the surface of the substrate using a photomultiplier tube (PMT);   classifying identifiable defects having different wavelengths from the mapping image having the wavelength corresponding to the band gap energy of the substrate obtained from the PMT into shapes and sizes and securing location data of the identifiable defects;   classifying stacking faults from the classified defects and assigning coordinates to each central position of the stacking faults using the location data;   sequentially irradiating the vertical illumination light for the stacking faults to which the coordinates are assigned;   acquiring a photoluminescence spectrum emitted from each stacking fault to which the vertical illumination light is irradiated with a spectrometer; and   comparing a peak wavelength in a region of 400 nm or more of the photoluminescence spectrum obtained from each stacking fault with a central wavelength in stacking fault database to classify characteristics of each stacking fault.