Properties of metamorphic materials and device structures on GaAs substrates

Effectiveness of non-linear graded buffers for In(Ga,Al)As metamorphic layers grown on GaAs (001)

“…This indicates that electron transport property of unipolar device is insensitive to the TD densities [20]. It should be noted that the electron mobilities of previously reported MHEMT with the intermediate In contents or InP lattice-matched HEMT are in the proximity of 10 4 cm 2 /V s at room temperature [21]. Our results are in good agreement with the levels for all the buffer types at room temperature in the least.…”

Low-Temperature and Metamorphic Buffer Layers

“…Buffer layers with linearly-graded composition, and therefore lattice constant, have been extensively investigated in a number of material systems, including In x Ga 1Àx As/GaAs [25,26,51,[96][97][98][99][100][101][102][103][104], In x Al 1Àx As/GaAs [34,75,103,[105][106][107][108][109][110], In x Al y Ga 1ÀxÀy As/GaAs [18,19,23,35,80,95,111], Si 1Àx Ge x /Si [112][113][114][115][116], In x Ga 1Àx P/GaAs [117][118][119], In x Ga 1Àx P/ GaP [120], ZnS y Se 1Ày /GaAs [102,121], and In x Ga 1Àx Sb/GaSb [122,123]. A possible advantage of continuous grading is that layer-by-layer growth may be maintained without the intrusion of island growth associated with large, abrupt changes in composition [119].…”

“…Linearly graded metamorphic buffers have been the widely used in device applications, including HEMTs [18,21,23,105,106,109,110,118,123,129,131,134,135], metal oxide semiconductor high electron mobility transistors (MOS HEMTs) [136], heterojunction bipolar transistors (HBTs) [113,117,118,137], LEDs [31,123], laser diodes [26,81,103,106,122], photodiodes [18,80,108,138,139], and solar cells [119]. Recent work with metamorphic HEMTs has emphasized In x Ga 1Àx As/In y Al 1Ày As quantum wells grown on GaAs (001) substrates by MBE [18,21,23,35,103,118,123,129,131,135].…”

Epitaxial nanowire formation in metamorphic GaAs/GaPAs short-period superlattices

“…5 Metamorphic heterostructures have been critical for advances in III-V multijunction photovoltaic devices, 6 as well as photodiodes and high-mobility transistors. 7 To obtain high-quality material, the grade incorporates a compositional "overshoot" to compensate for coherency strain, and is then terminated with a nominally unstrained displacement layer. [8][9][10] But few reports on the use of metamorphic grades for epitaxial nanostructures, which may offer solutions to next-generation device concepts, 11 are available.…”