How to use terahertz emission spectroscopy for wide bandgap semiconductor evaluation

Abstract

The time-domain waveforms of terahertz (THz) emission spectroscopy (TES) can tell us the ultrafast nature of the material photoresponse, and TES is becoming an essential tool to explore the advanced material functionalities and disclose the dynamics of the photocarriers. However, universal applications can not be reached without understanding physics in more detail over the broad dimensional range in the time-domain. We have applied TES and LTEM to Si-based materials and devices and proven that one can estimate various parameters, such as surface potential, work function, impurity doping density, defects density in passivation layers, surface state density, and so on, semi-quantitatively and non-contactly by just observing the THz radiation. In the present work, we review the TES application to wide bandgap semiconductors.

Non-contact measurement of dopant depth profile with terahertz emission spectroscopy

“…TES is a microscope that excites carrier by irradiating femtosecond laser pulses, shown as Figure 2, and LTEM analyzes and images terahertz waves caused by the movement of the charge inside semiconductor materials [10] [11] [12] [13] [14] [15]. Some applications have been reported for inspection for electrical faults in integrated circuits [16] and wide bandgap semiconductor [17].…”