Group III-Sb compound semiconductor is a promising material family for future transistors owing to their superior hole and electron transport properties for future CMOS and large controllable band offsets for high-performance TFETs. The heteroepitaxial growth of GaSb on Si substrate has significant advantage for volume fabrication of III-V ICs. High lattice mismatch between III-Sbï¿½s and Si results in 3D nucleation that is usually mitigated by incorporation of metamorphic nucleation layer (NL) with low adatom mobility, such as AlSb. We studied NL coverage rate and growth morphology of the AlSb NL grown by Migration-Enhanced molecular-beam Epitaxy (MEE) using in-situ Auger electron spectroscopy and AFM. The coverage kinetics was analyzed with Avramiï¿½s approach that allowed for accurate determination of nucleation density and evolution of the 3D islands. Effect of AlSb NL growth parameters and surface morphology on mobility and hole density in strained InGaSb quantum wells was studied. The optimum growth temperature of 300 0C is found for AlSb NL, resulting in room temperature Hall mobility of 660 cm2/V s at 3x1011 cm2 sheet hole density in the strained InGaSb QW p-channel. Using various designs of metamorphic superlattice buffers, thick GaSb layers were grown on Si(001) ,60 to  miscut Si(001), SOI (001) and GaAs (001) substrates by molecular beam epitaxy. Buffer design controls the defect density in GaSb that affects the electrical properties of the layers. Acceptor states related to the defects are quantified using differential Hall measurements in undoped progressively etched structures and TEM/AFM imaging. Optimized buffers allow to reduce defect density below 108 cm-2 that results in ~1x1017 cm-3 concentration of defect-related acceptors. The effect of growth-related defects (threading dislocations and microtwins) on hole concentration and mobility in strained InGaSb QWs is observed and quantified. The result on strained InGaSb p-MOSFETs grown on Al(Ga)Sb metamorphic buffers are summarized.
SUNY College of Nanoscale Science and Engineering, SUMCO Corporation
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