Step & Repeat mode, cross-section

  • Each alloy has a distinct spectral signature: band edge emission
  • C-compensated GaN easily distinguished
  • Growth defect in GaN:C leads to GaN:UID punch-through defect
  • Threading dislocation signature visible
  • Pixel size 40 nm, acquisition time 160s


Defect counting threading dislocation in GaN

Threading dislocation density

GaN on Sapphire wafer

Step and Repeat mode

  • High resolution cathodoluminescence: individual structures, dislocations
  • typical time/image: 2s, monochromatic map
  • <10 min per 150mm wafer at 50 images / wafer

automated image analysis

  • Threading dislocation density – 3.1E8 cm-2
  • Use case: MOCVD deposition control


SiC substrate quality control

Defect inspection & classification

Main advantages of Attolight CL

  • High resolution cathodoluminescence: defects
  • typical time/image: 3 minutes, hyperspectral map
  • 40 min / 150mm wafer for 10 images / wafer

Detected defects

  • Green band: 3C-SiC inclusions in 4H-SiC
  • Blue band: point defects
  • Red band: basal plane dislocation sheet (dark zone)
  • Dark lines: stacking faults
  • Dark points: dislocations
  • Automated defect classification classify defects