Growth of strained InGaSb quantum wells for p-FET on Si: Defects, interfaces, and electrical properties

A study of heteroepitaxial molecular beam epitaxy growth of strained p-channel InGaSb quantum well (QW) on lattice mismatched Si (100) using Al(Ga)Sb metamorphic buffers is presented in this paper. The migration enhanced epitaxy (MEE) technique was employed for AlSb nucleation layer (NL) on Si and analyzed using atomic force microscopy and in-situ Auger electron spectroscopy techniques to optimize growth conditions for continuous 2D buffer layers and improve surface quality of subsequent layers. Growth-related defects (threading dislocations, microtwins, and antiphase boundaries) and their effect on surface morphology and electrical properties of the QWs are analyzed with scanning electron microscope and transmission electron microscopy and correlated to the NL properties. The baseline data for defect density in the layers and resultant surface morphology are presented. Room temperature p-channel Hall mobility of 660 cm²/V s at 3 × 10¹¹ cm^-2 sheet hole concentration is achieved in InGaSb QWs using an optimized 15 monolayer AlSb MEE NL at 300 °C growth temperature.