Dislocation‐related electronic states in partially strain‐relaxed InGaAs/GaAs heterostructures grown by MOVPE

Abstract

By means of deep level transient spectroscopy (DLTS) a dislocation-related deep-level trap has been revealed in partially strain-relaxed InGaAs/GaAs heterostructures, grown by MOVPE. On the basis of the specific criteria containing DLTS-line shape and behaviour analysis as well as capture kinetics measurements, we were able to attribute the trap to "localized" states at the dislocation core or close to it. A direct comparison of DLTS concentration profiles and TEM results enable us to attribute the electron trap to 60° misfit dislocations lying at the heterostructure interface.

Anisotropic misfit strain relaxation in lattice mismatched InGaAs/GaAs heterostructures grown by MOVPE

“…Ref. [13]). The planar-and cross-sectional view specimens for the TEM observation were prepared using mechanical polishing and ion milling in order to achieve a thickness of electron transparency.…”

“…The compositions of all the epitaxial layers were obtained by means of X-ray rocking curve measurements, using the (0 0 4) reflection [14]. The results have been reported in our recent paper [13].…”

“…The In x Ga 1Àx As layers were intentionally undoped, but the background net doping concentration with donors indicated by C-V measurements was equal to about 10 16 cm À3 . More details on the characterization of electrical properties of the samples are given in our recent papers [12,13].…”

DLTS and PR Studies of Partially Relaxed InGaAs/GaAs Heterostructures Grown by MOVPE

“…Furthermore, the trap E1 shows a linear dependence on the logarithm of the filling time, so-called logarithmic capture kinetics (see inset in Fig. 2) and its depth concentration profile reveals a distinct maximum located at the epilayer-substrate interface [13]. On the basis of these results we attributed the trap E1 to core Solid State Phenomena Vols.…”

“…Two deep electron traps labeled E1 and E2 have been revealed in the DLTS spectrum measured the double correlation DLTS mode (DDLTS) [11], i.e. with two filling pulses, U 1 = 0 V and U 2 = -0,5 V and quiescent reverse voltage U R = -1 V. In our previous papers [12,13], the specific features connected with these two traps, like DLTS-line shape, DLTS-line behavior, capture kinetics and concentration depth profiles have been analysed in detail. The trap E2 with a deep level at 0.72 eV and a capture cross section equal to 4.22 × 10 -14 cm 2 , as calculated from the slope of the Arrhenius plot (Fig.…”