Tailoring the Valence Band Offset of Al2O3 on Epitaxial GaAs1–ySby with Tunable Antimony Composition

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• 作者：Jheng-Sin Liu ; Michael Clavel ; Mantu K. Hudait
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 30, 2015
• 年：2015
• 卷：7
• 期：51
• 页码：28624-28631
• 全文大小：523K
• ISSN：1944-8252

文摘

Mixed-anion, GaAs_1–ySb_y metamorphic materials with tunable antimony (Sb) compositions extending from 0 to 100%, grown by solid source molecular beam epitaxy (MBE), were used to investigate the evolution of interfacial chemistry under different passivation conditions. X-ray photoelectron spectroscopy (XPS) was used to determine the change in chemical state progression as a function of surface preclean and passivation, as well as the valence band offsets, conduction band offsets, energy band parameters, and bandgap of atomic layer deposited Al₂O₃ on GaAs_1–ySb_y for the first time, which is further corroborated by X-ray analysis and cross-sectional transmission electron microscopy. Detailed XPS analysis revealed that the near midpoint composition, GaAs_0.45Sb_0.55, passivation scheme exhibits a GaAs-like surface, and that precleaning by HCl and (NH₄)₂S passivation are mandatory to remove native oxides from the surface of GaAsSb. The valence band offsets, ΔE_v, were determined from the difference in the core level to the valence band maximum binding energy of GaAs_1–ySb_y. A valence band offset of >2 eV for all Sb compositions was found, indicating the potential of utilizing Al₂O₃ on GaAs_1–ySb_y (0 ≤ y ≤ 1) for p-type metal-oxide-semiconductor (MOS) applications. Moreover, Al₂O₃ showed conduction band offset of ～2 eV on GaAs_1–ySb_y (0 ≤ y ≤ 1), suggesting Al₂O₃ dielectric can also be used for n-type MOS applications. The surface passivation of GaAs_0.45Sb_0.55 materials and the detailed band alignment analysis of Al₂O₃ high-κ dielectrics on tunable Sb composition, GaAs_1–ySb_y materials, provides a pathway to utilize GaAsSb materials in future microelectronic and optoelectronic applications.