MBE growth of cubic Al_xIn_1–xN and Al_xGa_yIn_1–x–yN lattice matched to GaN

Abstract

.55. Jk, 78.66.Fd, 80.15.Hi, 82.80.Yc Ternary and quaternary cubic c-Al x In 1-x N/GaN and c-Al x Ga y In 1-x-y N/GaN heterostructures latticematched to c-GaN on freestanding 3C-SiC substrates were grown by plasma-assisted molecular beam epitaxy. The c-Al x Ga y In 1-x-y N alloy permits the independent control of band gap and lattice parameter. The ternary and quaternary films were grown at 620 °C. Different alloy compositions were obtained by varying the Al and Ga fluxes. The alloy composition was measured by Energy Dispersive X-ray Spectroscopy (EDX) and Rutherford Backscattering Spectrometry (RBS). X-ray reciprocal space map of asymmetric (-1-13) reflex were used to measure the lattice parameters and to verify the lattice match between the alloy and the c-GaN buffer. [3][4][5]. These films permit the independent control of band gap and lattice parameters through changes in the quaternary composition. However, growth of quaternary AlGaInN is a challenge due to the different bond length and desorption temperature of the binary compounds. Al-containing layers normally require much higher growth temperatures than In compounds. In has a high vapor pressure and therefore the growth temperature has to be lowered in order to increase the indium incorporation and to reduce the thermal dissociation of the In-N bonds.Recently, great interest in nonpolar III-nitrides -including cubic III-nitrides -has risen due to the absence of the built-in electrostatic field, which can limit the performance of devices. The cubic IIInitride polytype is metastable and can only be grown successfully in a narrow window of process conditions [6]. For the fabrication of electronic devices also in cubic group III nitrides it is essential to study the influence of strain and to grown lattice matched cubic AlGaInN and AlInN epilayers on GaN.In this work we demonstrate the growth of lattice matched cubic quaternary Al x Ga y In 1-x-y N/GaN heterostructures on freestanding 3C-SiC (001) substrates by plasma assisted molecular beam epitaxy (PAMBE).

Computational study of structural and elastic properties of random AlxGayIn1 −x−yN alloys

“…As can be seen in figure 4, the comparison of available data with our theoretical results reveals good agreement. It could be, of course, interesting to see how this relates to the structural properties of cubic Al x Ga y In 1−x−y N whose growth using molecular beam epitaxy was recently reported [48]. For completeness, in figure 4 we have also included the DFT findings, which again show the well known systematic tendency to underestimate the bond lengths.…”

“…Finally, one has to stress the fact that the above results apply to crystalline samples, e.g. such as those grown within MBE method by As et al [48]. Polycrystalline and amorphous phases require different computational approaches.…”

Computational study of structural and elastic properties of random AlGaInN alloys

“…As can be seen in figure 4, the comparison of available data with our theoretical results reveals good agreement. It could be, of course, interesting to see how this relates to the structural properties of cubic Al x Ga y In 1−x−y N which growth using molecular beam epitaxy was recently reported [48]. For completeness, in figure 4 we have also included the DFT findings which again show the well known systematic tendency to underestimate the bond lengths.…”

RF-MBE growth of Si doped cubic GaN and hexagonal phase incorporated c-AlGaN films on MgO(0 0 1) substrates

“…The higher electron mobility expected from the higher crystal symmetry in a cubic crystal is also advantageous for electronic devices. Cubic GaN (c-GaN) and cubic AlGaN (c-AlGaN) films have been grown on GaAs [1] and 3C-SiC [2,3]. For the growth of cubic III-nitride films, however, MgO will be an advantageous substrate material due to the higher thermal stability than GaAs.…”