High-resolution photoinduced transient spectroscopy as a new tool for quality assessment of semi-insulating InP

Abstract

High-resolution photoinduced transient spectroscopy has been applied to study grown-in defect centres in semi-insulating InP:Fe. The defect structure of crystals characterized by various values of Hall mobility has been compared. A number of defect centres with activation energies ranging from 10 to 640 meV were detected. They include shallow donor and acceptor impurities, native defects, shallow impurity–native defect complexes and iron-related defects. It was found that the Hall mobility is mainly affected by the shallow donor concentration which determines the ratio [Fe2+]/[Fe3+]. The electron lifetime is determined either by the iron concentration or the concentration of shallow impurities.

Contact Free Defect Investigation in as grown Fe-doped SI-InP

“…A defect level with an activation energy of approximately 0.6 eV in Fe-doped InP, as can be found in the case of the positive MD-PICTS peak, was reported by several other groups from conventional PICTS and other electrical measurements. This level is ascribed to the thermal emission of electrons from the ionized Fe 2+ -level into the conduction band [2][3][4][5][6][7]. This is why the occurrence of the positive MD-PICTS peak in our case is believed to be due to the same transition.…”

“…In general, conventional PICTS spectra of Fe-doped InP reported in the literature show one dominant positive peak with a corresponding activation energy of 0.6 to 0.68eV. It is ascribed to the electron emission from the ionized Fe 2+ -charge state into the conduction band [2][3][4][5][6][7]. Positive PICTS signals with an activation energy of 0.68 to 0.78eV are also assigned to the iron defect level.…”

“…Beside of the iron level many other defect levels are known from electrical measurements on InP in the literature. Levels with activation energies above 0.02 eV are mainly ascribed to native defects or compound defects of intrinsic defects and impurities [7,9].…”

<title>Application of least-squares support vector machine (LS-SVM) to determination of deep level defect centers parameters in semi-insulating GaAs</title>

“…One of the useful techniques, which allow to investigate deep level defects parameters in semi-insulating semiconductors is Photoinduced Transient Spectroscopy (PITS) [6,7,8]. This method is based on measurement of the photocurrent excited by optical pulse falling on semiconductor sample.…”

Recent Research Results on Deep Level Defects in Semi-Insulating InP-Application to Improve Material Quality

“…With the progress of device miniature, higher performance and reliability, high quality SI-InP substrate with low defect concentration, high electrical uniformity and thermal stability is required. However, deep level defects have been frequently detected in Fe-doped SI-InP [1][2][3][4][5][6]. The deep level defects in the SI-InP influence electrical compensation, destroy lattice perfection, enhance dislocation climb, etc.…”