Method of measuring electric characteristics of flat substrate using terahertz light

摘要

A terahertz light L3 is repeatedly applied to a semiconductor substrate (5) to receive a reflection light L4 from the substrate (5). The reflection light L4 includes a multiple-reflection light occurred in the substrate (5). When the reflection light L4 is received, a delay time length required to lead a probe pulse light L2 to a terahertz light detector (4) is set so as not detect at the terahertz light detector (4) the reflection light L4 reaching via surfaces other than the illuminated surface of the semiconductor substrate (5). A time region spectrometry method is used to measure the time-series waveform of the field intensity of the detected reflection light L4, and the electric characteristic parameters of the substrate (5) are calculated from a spectral reflectance determined based on the time-series waveform.