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Journal ArticleDOI

Effect of post deposition annealing and post metallization annealing on electrical and structural characteristics of Pd/Al2O3/6H-SiC MIS capacitors

11 Apr 2018-Microelectronics International (Emerald Publishing Limited)-Vol. 35, Iss: 2, pp 65-73
TL;DR: In this paper, the effect of post-deposition rapid thermal annealing (PDA) and post-metallization anneeling (PMA) on the structural and electrical characteristics of Pd/Al2O3/6H-SiC capacitors was investigated.
Abstract: Purpose Al2O3 used as gate dielectric enables exploitation of higher electric field capacity of SiC, improving capacitive coupling and memory retention in flash memories. Passivation of traps at interface and in bulk which causes serious threat is necessary for better performance. The purpose of this paper is to investigate the effect of post-deposition rapid thermal annealing (PDA) and post-metallization annealing (PMA) on the structural and electrical characteristics of Pd/Al2O3/6H-SiC capacitors. Design/methodology/approach Al2O3 film is deposited by ALD; PDA is performed by rapid thermal annealing (RTA) in N2 at 900°C for 1 min and PMA in forming gas for 10 and 40 min. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements data are studied in addition to capacitance-voltage (C-V) and current-voltage (I-V) characteristics for the fabricated Pd/Al2O3/SiC capacitors. Conduction mechanism contributing to the gate leakage current is extracted for the entire range of gate electric field. Findings RTA forms aluminum silicide at the interface causing an increase in the density of the interface states and gate leakage current for devices with an annealed film, when compared with an as-deposited film. One order improvement in leakage current has been observed for the devices with RTA, after subjecting to PMA for 40 min, compared with those devices for which PMA was carried out for 10 min. Whereas, no improvement in leakage current has been observed for the devices on as-deposited film, even after subjecting to PMA for 40 min. Conduction mechanisms contributing to gate leakage current are extracted for the investigated Al2O3/SiC capacitors and are found to be trapfilled limit process at low-field regions; trapassisted tunneling in the mid-field regions and Fowler–Nordheim (FN) tunneling are dominating in high-field regions. Originality/value The effect of PDA and PMA on the structural and electrical characteristics of Pd/Al2O3/SiC capacitors suitable for flash memory applications is investigated in this paper.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a wide bandgap and low intrinsic carrier concentration enable longer charge retention time and high-temperature operation of Silicon carbide (SiC) flash memory devices.
Abstract: Wide bandgap and resulting low intrinsic carrier concentration enable longer charge retention time and high-temperature operation of Silicon carbide (SiC) flash memory devices. However, charge leak...

1 citations

Journal ArticleDOI
TL;DR: In this paper , the effects of different ultrasonic-assisted loading degrees on the microstructure, mechanical properties and the fracture morphology of Cu/Zn+15%SAC0307 +15%Cu/Al solder joints were investigated.
Abstract: Purpose This paper aims to investigate the effects of different ultrasonic-assisted loading degrees on the microstructure, mechanical properties and the fracture morphology of Cu/Zn+15%SAC0307+15%Cu/Al solder joints. Design/methodology/approach A new method in which 45 μm Zn particles were mixed with 15% 500 nm Cu particles and 15% 500 nm SAC0307 particles as solders (SACZ) and five different ultrasonic loading degrees were applied for realizing the soldering between Cu and Al at 240 °C and 8 MPa. Then, SEM was used to observe and analyze the soldering seam, interface microstructure and fracture morphology; the structural composition was determined by EDS; the phase of the soldering seam was characterized by XRD; and a PTR-1102 bonding tester was adopted to test the average shear strength. Findings The results manifest that Al–Zn solid solution is formed on the Al side of the Cu/SACZ/Al joints, while the interface IMC (Cu5Zn8) is formed on the Cu side of the Cu/SACZ/Al joints. When single ultrasonic was used in soldering, the interface IMC (Cu5Zn8) gradually thickens with the increase of ultrasonic degree. It is observed that the proportion of Zn or ZnO areas in solders decreases, and the proportion of Cu–Zn compound areas increases with the variation of ultrasonic degree. The maximum shear strength of joint reaches 46.01 MPa when the dual ultrasonic degree is 60°. The fracture position of the joint gradually shifts from the Al side interface to the solders and then to the Cu side interface. Originality/value The mechanism of ultrasonic action on micro-nanoparticles is further studied. By using different ultrasonic loading degrees to realize Cu/Al soldering, it is believed that the understandings gained in this study may offer some new insights for the development of low-temperature soldering methodology for heterogeneous materials.
References
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Journal ArticleDOI
TL;DR: In this paper, the binding energy of the C1s and N1s XPS peaks in melamine (C3N6H6) was determined relative to the XPS peak for carbon contamination (adventitious carbon).

445 citations

Journal ArticleDOI
TL;DR: In this article, the electrical properties of both amorphous and epitaxial Al2O3 films were studied by capacitancevoltage and current-voltage measurements of metal-oxide-semiconductor capacitors.
Abstract: Stoichiometric and pure Al2O3 gate dielectric films were grown on n-type 4H-SiC by a thermal atomic layer deposition process. The electrical properties of both amorphous and epitaxial Al2O3 films were studied by capacitance-voltage and current-voltage measurements of metal-oxide-semiconductor capacitors. A dielectric constant of 9 and a flatband voltage shift of +1.3V were determined. A leakage current density of 10−3A∕cm2 at 8MV∕cm was obtained for the amorphous Al2O3 films, lower than that of any high-κ gate oxide on 4H-SiC reported to date. A Fowler-Nordheim tunneling mechanism was used to determine an Al2O3∕4H-SiC barrier height of 1.58eV. Higher leakage current was obtained for the epitaxial γ-Al2O3 films, likely due to grain boundary conduction.

146 citations

Journal ArticleDOI
TL;DR: The obtained photoluminescence results with a decay time of nanoseconds suggest that the θ-Al2O3 phase could be an exceptional choice for next generation fast optical sensors.
Abstract: Herein, we have demonstrated the high yield facile growth of Al2O3 nanowires of uniform morphology with different polymorph phases (e.g. γ, δ and θ) via a hydrothermal method with varying calcination temperatures. The synthesized θ-Al2O3 nanowires were well characterized by XRD, FTIR, SEM/EDAX, AFM and HRTEM techniques. Microstructural analysis confirmed that the dimensions of the individual θ-Al2O3 nanowires are approximately in the ranges 5–20 nm in width and 40–150 nm in length, and the aspect ratio is up to 20. AFM results evidenced the uniform distribution of the nanowires with controlled morphology. Furthermore, UV-vis spectroscopic data reveal that the estimated optical band gap of the θ-Al2O3 nanowires was ∼5.16 eV. The photoluminescence spectrum exhibits blue emission upon excitation at a wavelength of 252 nm. Time-resolved spectroscopy demonstrates that these nanowires illustrate a decay time of ∼2.23 nanoseconds. The obtained photoluminescence results with a decay time of nanoseconds suggest that the θ-Al2O3 phase could be an exceptional choice for next generation fast optical sensors.

66 citations

Journal ArticleDOI
TL;DR: In this paper, a comparison between palladium (Pd) and platinum (Pt) as gates in metal-oxide-semiconductor devices in different hydrogen/oxygen mixtures was made.
Abstract: A comparison is made between palladium (Pd) and platinum (Pt) as gates in metal‐oxide‐semiconductor devices in different hydrogen/oxygen mixtures. We have shown that Pd is superior as gate material for detection of small amounts of hydrogen in room ambient. At high hydrogen concentrations Pt would be more suitable.

56 citations