Quantitative Imaging of MOS Interface Trap Distribution by Using Local Deep Level Transient Spectroscopy

The local deep level transient spectroscopy, which measures traps with high lateral resolution using sharp tip, was investigated as functions of DC bias. The results showed that the physical origin which was detected by local-DLTS was mainly interface trap. Furthermore, two-dimensional (2D) quantitative profiling of interface traps as a function of time constant was demonstrated. Comparison between images of different time constant revealed that interface traps with different time constant had different lateral distribution, which suggests that 2D distribution of interface traps depends on their energy level. These results show that local-DLTsis promising for microscopic investigation of interface traps.