Molecular beam epitaxy growth of high electron mobility InAs/AlSb deep quantum well structure

Abstract

InAs/AlSb deep quantum well (QW) structures with high electron mobility were grown by molecular beam epitaxy (MBE) on semi-insulating GaAs substrates. AlSb and Al0.75Ga0.25Sb buffer layers were grown to accommodate the lattice mismatch (7%) between the InAs/AlSb QW active region and GaAs substrate. Transmission electron microscopy shows abrupt interface and atomic force microscopy measurements display smooth surface morphology. Growth conditions of AlSb and Al0.75Ga0.25Sb buffer were optimized. Al0.75Ga0.25Sb is better than AlSb as a buffer layer as indicated. The sample with optimal Al0.75Ga0.25Sb buffer layer shows a smooth surface morphology with root-mean-square roughness of 6.67 Å. The electron mobility has reached as high as 27 000 cm2/Vs with a sheet density of 4.54 × 1011/cm2 at room temperature.

Ga composition effects on the electrical parameters of (Al,Ga)Sb/InAs two-dimensional electron gas

“…The Al 0.7 Ga 0.3 Sb layer with high Al composition is of great resistance, which can efficiently eliminate the leakage current for the gate control in practical devices. Besides, the addition of Ga to the AlSb is useful to obtain better crystal qualities and transport properties [27,28]. Afterwards, the AlSb/InAs/Al 1−x Ga x Sb QWs with different x were deposited, and a GaSb cap layer was used to protect (Al,Ga)Sb from oxidation.…”

Stress effects on electronic properties of GaAs thin film

“…One is the lattice mismatch between the crystal lattice constant of film and the substrate. 7,8 The other is the thermal mismatch due to the different thermal expansion coefficients. 9 The influence of these factors on the performance of the devices cannot be ignored.…”

Design, fabrication, and analysis of p-channel arsenide/antimonide hetero-junction tunnel transistors

“…The GaAs 0.022 Sb 0.978 layer may be introduced during the switching from GaSb channel layer to InAs source. A proper switching sequence of III/V elements is critical for engineering an abrupt hetero-interface during the growth of mixed As/Sb materials, [25][26][27] otherwise the intermixing between As and Sb atoms will result in uncontrolled layer composition at the hetero-interface, which will cause the change of strain relaxation properties of the epilayer grown on this interface. 28 The change of strain relaxation properties may introduce high density dislocations at the hetero-interface and within the InAs source layer, which explains the high I OFF in the fabricated hetJ pTFET.…”