Principle
The high-speed, non-destructive defect inspection technology for compound semiconductor wafers developed by TimeTechSpectra is based on photogenerated carrier dynamics spectroscopy. Under optical excitation, electron–hole pairs are generated and exhibit a characteristic lifetime in an ideal lattice. However, crystallographic defects such as dislocations, stacking faults, and point defects introduce carrier trapping and non-radiative recombination, resulting in reduced local carrier concentration and shortened lifetimes.
By analyzing the spatial distribution and time-resolved decay dynamics of photogenerated carriers, the location, distribution, and density of defects can be quantitatively characterized. This approach integrates transient absorption/reflection imaging and time-resolved photoluminescence spectroscopy, relying on excited-state absorption and radiative recombination signals, respectively, enabling high-sensitivity, high-throughput, wafer-scale inspection across materials including SiC, GaN, Ga₂O₃, GaAs, and InP.
