| Summary: | 博士 === 國立清華大學 === 材料科學工程學系 === 102 === Antimonide-based compound semiconductors are emerging materials for the high-speed low-power electronics in complementary metal-oxide-semiconductor (CMOS) industry beyond 7-5 nm node technology, mid-infrared sensors/detectors in military/medical industry, and solar cells in green energy industry, due to their wide range of tunable band gaps and high carrier mobilities among the III-V compound semiconductors. However, despite the increasing demand in antimonide-based material system for realizing the high performance transistors operated at ultra-low driving voltage (< 0.5 V), the attainment of a high-/(In)GaSb interfaces possessing the low interfacial density of states (Dit) as well as the acceptable thermal stability has yet been achieved.
In this dissertation, by depositing the rare-earth oxide, Y2O3, via molecule beam epitaxy (MBE) and atomic layer deposition (ALD), respectively, we have succeeded in passivating the GaSb(100) surface, which forms a thermally stable (> 500 oC) and well-bonded high-/GaSb interface. A detailed comparison between the samples with Y2O3 deposited by MBE and ALD, respectively, has been carried out with respect to the interface chemical bondings and electrical properties. Moreover, dependence of the deposition temperatures of MBE-Y2O3 to the interfacial properties and related MOS device performance has also been discussed. The corresponding chemical bondings and subsequent reactions for the Y2O3/GaSb interface were studied using in situ angle-dependent X-ray photoelectron spectroscopy (XPS). Moreover, the electrical properties for the Y2O3/GaSb interface were studied in terms of the conventional capacitance-voltage (C-V) and leakage current density-electric field (Jg-Eg) characteristics along with the temperature-dependent conductance method (CM) measurements and Gray-Brown (G-B) method analysis for the interfacial density of states (Dit) extraction. Consequently, the self-aligned inversion channel GaSb p-MOSFETs have been fabricated and yielded a record high saturation drain current density (Id,sat) of 130 A/m and maximum transconductance (Gm,max) of 90 S/m. Besides, a low subthreshold slope (S.S.) of 147 mV/decade and a peak field-effect hole mobility (h,FE) of 200 cm2/V-s were also obtained from the GaSb p-MOSFETs with 1 μm-gate-length.
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