Noncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating GaAs Wafers

Abstract

Articles you may be interested inBroadening effects and ergodicity in deep level photothermal spectroscopy of defect states in semi-insulating GaAs: A combined temperature-, pulse-rate-, and time-domain study of defect state kinetics A purely optical deep level photothermal spectroscopy has been developed for the defect-state characterization of semi-insulating ͑SI͒ GaAs wafers. The methodology utilizes near infrared sub-band-gap absorption to monitor the thermal emission of traps after an optical filling pulse, and the data are analyzed in a rate-window manner by a lock-in amplifier. The technique has been applied to a vertical-gradient-freeze grown SI-GaAs wafer, and the very first results are presented.

Regenerative feedback resonant circuit to detect transient changes in electromagnetic properties of semi-insulating materials

“…36 Measurements of microwave photoconductive decay are now being developed as a sensitive measure of the photoinduced carrier lifetimes. [37][38][39][40] The need is to understand, nondestructively and using noncontact techniques, the quasisteady-state photoconductance of nascent Si wafers and/or surface passivated for optoelectronic and photovoltaic devices, such as high efficiency solar cells. The measurements in Ref.…”

Direct-search deep level photothermal spectroscopy: An enhanced reliability method for overlapped semiconductor defect state characterization

“…The sample used for the measurement is a vertical gradient freeze-grown GaAs provided by AXT Inc. A detailed discussion of the experimental setup can be found in our earlier papers. 3,7 Both temperature-and frequency-scanned DLPTS spectra shown in Fig. 2 are utilized for the fitting.…”

Broadening effects and ergodicity in deep level photothermal spectroscopy of defect states in semi-insulating GaAs: A combined temperature-, pulse-rate-, and time-domain study of defect state kinetics

“…The thermal emission rate at each peak temperature can be calculated by e n ͑T peak ͒ = 2.869f, 8 where f =1/ T 0 is the pulse repetition frequency. Based on Eq.…”

“…In earlier papers, we introduced an all optical DLPTS, 8,9 which utilizes a subbandgap laser to monitor the concentration of free carriers and the density of occupied states resulting from photoexcitation by a modulated coincident superbandgap laser beam. The technique was applied to semiinsulating ͑SI͒-GaAs and a well-defined peak, associated with the EL3 level was observed in the above room temperature photothermal spectrum.…”

“…The technique was applied to semiinsulating ͑SI͒-GaAs and a well-defined peak, associated with the EL3 level was observed in the above room temperature photothermal spectrum. The spectrum was then fitted by both simplified 8 and more comprehensive 9 theories. Although the comprehensive theory induced some broadening due to the consideration of carrier capturing processes, the experimental spectrum was still broader than the theoretical fits.…”