Non-Destructive Testing of Semiconductors Using Surface Acoustic Wave

摘要

The major emphasis of this report is on a new and novel surface acoustic wave (SAW) device which has been developed under this grant for use in the nondestructive determination of the electronic properties of semiconductors. The technique uses surface acoustic waves on a piezoelectric substrate. The electric field associated with the SAW interacts with free carriers of a semiconductor placed near the piezoelectric surface. The interaction generates detectable currents in the semiconductor and attenuates the SAW. By observing these effects while varying external parameters such as temperature, applied acoustic power, SAW frequency, semiconductor surface irradiation and bias voltage, the desired information is obtained. The properties that can be determined by this non contact technique include the bulk and surface conductivity, generation lifetime, surface recombination velocity, the location in the energy gap of traps, surface states, and interface states, trap emission and absorption times and storage times in the depletion layer.