Evaluation of semiconductor materials and devices by laser-induced terahertz emissions (Conference Presentation)

I introduce recent studies on evaluation of interface and surface of semiconductor materials and devices with laser-induced terahertz emission spectroscopy and imaging that measure and visualize THz emissions from the materials and devices excited by femtosecond laser pulses. The waveforms of lase-induced THz emissions refrect the dinamics of photoexcited carriers at the area excited by the laser pulses, therefore we can extract various physical properties of the samples using this phenomena in principle. In this study, we have applied this technique to characterize local properties of semiconductor materials and devices such as solar cells, wide-gap semiconductors and Metal-Oxide-Semiconductor (MOS) devices. As a result, we demonstrated that it was possible to evaluate electric polarization, surface potentials, defects, damage, performance deterioration, which were difficult with conventional methods.