Browsing by Author "Li, T. H."

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Characterization of inter-poly high-kappa dielectrics for next generation stacked-gate flash memories
(2006)
Chen, Y. Y.
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Li, T. H.
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Kin, K. T.
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Chien, C. H.
;
Lou, J. C.
In this paper, the inter-poly dielectric (IPD) thickness, scaling, and reliability characteristics of Al2O3 and HfO2 IPDs are studied, which are then compared with TEOS IPD. Regardless of deposition tools, drastically leakage current reduction and reliability improvements have been demonstrated by replacing TEOS IPD with high-permittivity (high-kappa) IPDs, which are suitable for mass production applications in the future. Moreover, MOCVD deposition can be used to further promote dielectric reliability when compared to reactive-sputtering deposition. By using MOCVD deposition, the QRD can be significantly improved, in addition to reduced leakage current density, enhanced breakdown voltage and effective breakdown field. Our results clearly demonstrate that both MOCVD-Al2O3 and MOCVD-HfO2 IPD possess great potential for next generation stacked-gate flash memories.
Designing novel lightweight, high-strength and high-plasticity Ti-x(AlCrNb)(100-x) medium-entropy alloys
(2020-02-01)
Liao, Y. C.
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Li, T. H.
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Tsai, P. H.
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Jang, J. S. C.
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Hsieh, K. C.
Due to the demand for reduced energy consumption by transportation vehicles, lighter weight high-entropy alloys (with density comparable to that of commercial Ti alloys around 4.5-5 g/cm(3)) are attracting more attention in terms of alloy design and application as structural materials. In this study, a nonequiatomic quaternary alloy system, Ti-x(AlCrNb)(100-x), was designed through the calculation of phase diagrams. Simulation results reveal that a single body-centered cubic (BCC) phase can be formed and can be stable at temperatures above 950 degrees C. Accordingly, a series of Ti-x(AlCrNb)(100-x), (x = 45-80) alloys containing a BCC structure were prepared through vacuum arc melting and rapid cooling. The designed alloys can exhibit desirable mechanical properties with high compression yield strength about 1500 MPa, high compression fracture strength about 1800 MPa and high compression plasticity more than 30% at room temperature. Moreover, the Ti65 alloy can demonstrate a tensile strength of 1200 MPa with a tensile elongation of 32%, after a homogenization treatment for 24 h. The specific compression and tensile strength can reach 0.36 and 0.24 GPa cm(3)/g.