Interfacial misfit array formation for GaSb growth on GaAs

We have observed the evolution of the accumulated stress during heteroepitaxial growth of highly lattice mismatched AlSb on GaAs by measuring the deformation of the substrate as a function of time. High resolution transmission electron microscopy images show almost all of the plastic relaxation is accommodated by an array of 90° misfit dislocations at the interface. The in-plane lattice parameter of the resulting metamorphic AlSb is slightly smaller (0.3%) than the bulk value and perfectly matches the lattice parameter of bulk GaSb. It is, therefore, possible to grow nearly stress-free GaSb on GaAs using a metamorphic AlSb buffer layer.

mentioning

confidence: 82%

“…cases of IMF metamorphic growth, such as GaAs on Si, 13 GaSb on GaAs, 3 and AlSb on Si. 4 During the first 0.76 ML of AlSb on GaAs growth, the accumulated stress slope (0.59 6 0.03 N/m in the first 0.76 ML) corresponds approximately to the value expected for pseudomorphic growth.…”

Section: -mentioning

confidence: 99%

Relaxation dynamics and residual strain in metamorphic AlSb on GaAs

Ripalda

Sanchez

Taboada

et al. 2012

“…These propagate laterally, rather than into the overlying epilayer, and defect densities as low as 5 Â10 5 cm À2 have been reported for bulk GaSb on GaAs. 9 Derivative devices have already been demonstrated, including lasers, 10 light emitting diodes (LEDs), 11 and photodiodes, 12 and have shown similar levels of performance to their lattice-matched equivalents. In addition, SLS-based nBn detectors have already been demonstrated using the IMF growth mode.…”

mentioning

confidence: 99%

Mid-infrared InAs0.79Sb0.21-based nBn photodetectors with Al0.9Ga0.2As0.1Sb0.9 barrier layers, and comparisons with InAs0.87Sb0.13 p-i-n diodes, both grown on GaAs using interfacial misfit arrays

Craig

Marshall

Tian

et al. 2013

InAs0.79Sb0.21-based nBn photodetectors were fabricated on a GaAs substrate, using the interfacial misfit array growth mode. Reductions in the dark current density of more than two orders of magnitude at 300 K and more than six orders of magnitude at 200 K were found, in comparison with an InAs0.87Sb0.13 p-i-n diode. At −0.5 V applied bias, the dark currents were found to be diffusion limited above 150 K. Background limited infrared photodetection and R0A values in excess of 106 Ωcm2 were observed at 150 K. Spectral response measurements revealed a cut-off wavelength of 5.3 μm at 200 K.

“…[1][2][3][4][5][6] Although it could be expected to obtain only the 90 MDs due to their energetically favourable state with respect to the 60 ones, both types are usually observed in this system at similar growth conditions. [7][8][9] The 60 MDs generate threading dislocations (TDs), which emerging from the interface glide to the surface resulting in material degradation, decrementing its electrical and optical properties.…”

mentioning

confidence: 99%

“…The MD separation was determined to be around 5.7 nm, which corresponds to 13 GaSb lattice sites and 14 GaAs lattice sites. 2 Thus, every 14th Ga atom had a pair of dangling bonds to accommodate the larger Sb atom in the next (001) plane. Note that in sample A, all these MDs are located in the same (001) interface plane and an identical misfit array was also observed in the GaSb/GaAs interface along the perpendicular [110] direction.…”

mentioning

confidence: 99%

Solid solution strengthening in GaSb/GaAs: A mode to reduce the TD density through Be-doping

Gutiérrez

Araújo

Jurczak

et al. 2017

The need for a low bandgap semiconductor on a GaAs substrate for thermophotovoltaic applications has motivated research on GaSb alloys, in particular, the control of plastic relaxation of its active layer. Although interfacial misfit arrays offer a possibility of growing strain-free GaSb-based devices on GaAs substrates, a high density of threading dislocations is normally observed. Here, we present the effects of the combined influence of Be dopants and low growth temperature on the threading dislocation density observed by Transmission Electron Microscopy. The Be-related hardening mechanism, occurring at island coalescence, is shown to prevent dislocations to glide and hence reduce the threading dislocation density in these structures. The threading density in the doped GaSb layers reaches the values of seven times less than those observed in undoped samples, which confirms the proposed Be-related hardening mechanism.