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Effect of HCl Cleaning on InSb-Al<sub>2</sub>O<sub>3</sub> MOS Capacitors
摘要: In this work, the role of HCl treatments on InSb surfaces and InSb-Al2O3 dielectric interfaces is characterised. X-ray photoelectron spectroscopy (XPS) measurements indicate that HCl diluted in and rinsed with isopropanol (IPA) results in a surface layer of InCl3 which is not present for similar HCl-water processes. Furthermore, this InCl3 layer desorbs from the surface between 200°C and 250°C. Metal-oxide-semiconductor capacitors (MOSCAPs) were fabricated using atomic layer deposition (ALD) of Al2O3 at 200°C and 250°C and the presence of InCl3 was associated with a +0.79 V flatband voltage shift. The desorption of the InCl3 layer at 250°C reversed this shift but the increased process temperature resulted in increased interface-trapped charge (Dit) and hysteresis voltage (VH). This shift in flatband voltage, which does not affect other figures of merit, offers a promising route to manipulate the threshold voltage of MOS transistors, allowing enhancement-mode and depletion-mode devices to be fabricated in parallel.
关键词: surface cleaning,III-V,ALD,Al2O3,InSb,dielectric interface,MOSCAP,HCl
更新于2025-11-14 17:28:48
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Molecular beam homoepitaxy on bulk AlN enabled by aluminum-assisted surface cleaning
摘要: We compare the effectiveness of in situ thermal cleaning with that of Al-assisted cleaning of native surface oxides of bulk AlN for homoepitaxial growth by molecular beam epitaxy. Thermal deoxidation performed at 1450 (cid:2)C in vacuum results in voids in the AlN substrate. On the other hand, Al-assisted deoxidation at (cid:3)900(cid:2)C results in high-quality AlN homoepitaxy, evidenced by clean and wide atomic terraces on the surface and no extended defects at the growth interface. This study shows that Al-assisted in situ deoxidation is effective in removing native oxides on AlN, providing a clean surface to enable homoepitaxial growth of AlN and its heterostructures; furthermore, it is more attractive over thermal deoxidation, which needs to be conducted at much higher temperatures due to the strong bonding strength of native oxides on AlN.
关键词: surface cleaning,homoepitaxy,molecular beam epitaxy,aluminum-assisted cleaning,AlN
更新于2025-09-23 15:21:01
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Effect of N <sub/>2</sub> /H <sub/>2</sub> plasma on GaN substrate cleaning for homoepitaxial GaN growth by radical-enhanced metalorganic chemical vapor deposition (REMOCVD)
摘要: We developed a new method of GaN growth using Radical-Enhanced Metalorganic Chemical Vapor Deposition (REMOCVD) technology by which Gallium Nitride (GaN) grows at low temperatures without ammonia gas. In this method, we investigated the effect of N2/H2 plasma on the GaN substrate surface cleaning prior to the growth of homoepitaxial GaN. In-situ reflection high-energy electron diffraction (RHEED) and atomic force microscope (AFM) were used to investigate the surface morphology of the cleaned GaN substrates. The interface between GaN substrate and homoepitaxially grown GaN by REMOCVD was evaluated by transmission electron microscope and the crystal quality was evaluated by X-ray diffraction. The in-situ N2/H2 plasma cleaning at 600 ?C shows a smooth surface morphology with streak diffraction lines observed by RHEED. Since the homoepitaxial growth of GaN was performed at 800 ?C, the cleaned GaN substrate temperature was ramped up from 600 ?C to 800 ?C with and without plasma exposure to compare the effect of plasma. Homoepitaxially grown GaN on GaN substrates whose temperature was ramped up with plasma exposure showed good crystal quality with no threading dislocations at the interface. It was found that N2/H2 plasma plays a significant role in the GaN surface cleaning for good quality crystal growth.
关键词: surface cleaning,homoepitaxial growth,N2/H2 plasma,GaN,REMOCVD
更新于2025-09-04 15:30:14