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Electrical properties of commercial silicon carbide (SiC) Schottky rectifiers are investigated through the measurement and analysis of the forward current-voltage (I-V) (C-V) characteristics in a large temperature range. Some of devices show distinct discrepancies in specific ranges of their electrical characteristics, especially the excess current dominates at voltage <1 V and temperature <300 K. Standard deep level transient spectroscopy (DLTS) revealed the presence of a single deep-level defect with activation energy of about 0.3 eV, exhibiting the features characteristic for extended defects (e.g. dislocations), such as logarithmic capture kinetics. Furthermore, high-resolution Laplace DLTS showed that this deep level consists actually of three closely spaced levels with activation energies ranging from about 0.26 eV to 0.29 eV. A strong correlation between these two techniques implies that the revealed trap level is due to extended defects surrounded by point traps or clusters of defects. On the basis of obtained specific features of the deep-level defect, it was proposed that this defect is arguably responsible for the observed Schottky barrier inhomogeneities. [ABSTRACT FROM AUTHOR]

Highlights: [•] DLTS technique was used to study deep electron traps in 4H-SiC JBS rectifiers. [•] Five single-peak and one dominant double-peak deep electron traps were revealed. [•] The traps were attributed to impurity-related or intrinsic defects in n-type 4H-SiC epilayers. [•] The dominant deep electron trap at EC –0.68eV was attributed to Z 1/Z 2 defect. [ABSTRACT FROM AUTHOR]

Abstract: The electrical and optical properties of the lattice-mismatched InGaAs/GaAs heterostructures, with partial strain relaxation, were studied by deep level transient spectroscopy (DLTS) and photoreflectance (PR) spectroscopy, respectively. In the samples one of deep electron traps, revealed by DLTS, was ascribed to misfit dislocations at the interface, for which capture kinetics, concentration depth profiles and the type of electronic states have been specified. Room temperature PR spectroscopy was used for analysing the effect of residual strain on the optical response from the samples, i.e. interband transitions and the valence band splitting. [Copyright &y& Elsevier]

Abstract: Electronic properties of strain-induced dislocations in partially relaxed InGaAs/GaAs heterostructures with a small lattice mismatch have been studied by means of deep-level transient spectroscopy (DLTS). DLTS investigations carried out with Schottky contacts revealed one deep electron trap, at about EC −0.57eV. The trap has been attributed to electron states associated with α misfit dislocations lying at the interface between the epilayer and the substrate. Thorough studies including DLTS-line shape, DLTS-line behaviour analysis as well as capture kinetics and deep profile measurements made possible to specify the type of electronic states associated with dislocations. We relate the electron trap to “localized” states at misfit dislocations. [Copyright &y& Elsevier]

Convenient and simple criteria are proposed enabling one to distinguish between deep level point and extended defects (e.g. dislocations) in DLTS measurements. The approach is based on earlier reports of several authors and on our own experiences in the field of DLTS data analysis for III-V semiconductors. It consists of standard DLTS measurements widened by line shape and line behaviour analysis, as well as capture kinetics measurements. In the first part, the paper presents a survey of the literature on the analysis of DLTS signals originating from dislocations. In the second part, selected experimental data on distinguishing and identifying deep point and extended defects, in GaAs/GaAs and InGaAs/GaAs heterostructures, are presented. [ABSTRACT FROM AUTHOR]