This paper discusses the capacitance-voltage (C-V ) characteristics of Al 2 O 3 /InSb/Si (1 1 1) MOS diodes grown using MBE via InSb bi-layer with special care to the surface reconstruction. This growth technique is based on our finding that the InSb layer grown on a Si (1 1 1) substrate is rotated by 30 • with respect to the substrate under certain initial conditions. This rotation drastically reduces the lattice mismatch from 19.3% to 3.3%, and improves the crystal quality of an InSb layer. To investigate the possibilities of InSb MOSFETs on Si substrates, we fabricated MOS diodes having an Al 2 O 3 insulator film deposited by atomic layer deposition. C-V characteristics were measured both at RT and 77 K. It was found that the InSb grown on Si shows a degraded C-V curve compared to the InSb substrate, even though the mobility of the grown layer is quite high. We also investigated the effects of InSb thickness on the C-V characteristics of the MOSFETs. It was found that the quality of MOS diodes first degrades when decreasing the InSb thickness from 1 μm to 50 nm; further reduction of the InSb thickness improves it again. It was demonstrated that the MOS diode having a 10 nm InSb layer shows a good C-V curve, which is comparable to that of the InSb substrate. Finally, we discussed the possibility of the InSb/Si pseudomorphic MOSFETs.

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V-shaped grooves were prepared by patterning of line and space (LS) using photolithography and BHF etching, and anisotropic etching using hot KOH solution on patterned 100 nm-SiO2/Si(001) substrate. The V-shaped grooves consist of two 111 planes. The width of grooves was varied from 2 to 10 µm while keeping intervals ( 001 planes with 1 µm width) between grooves. The heteroepitaxial growth of InSb films on the V-grooved Si(001) substrate was carried out by using a two-step growth procedure in an ultra-high vacuum chamber. The samples were characterized by X-ray diffraction (XRD) and scanning electron micrograph as a function of the space width of LS. From comparison of the XRD pattern of InSb films grown on Si(001) substrate with and without the V-grooves, we found that InSb crystals were heteroepitaxially grown not only on the 111 surface of the V-shaped grooves but also on the narrow (at least <3 µm) (001) surfaces.

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