Nagoya University · Engineering
Professor Shih-Nan Hsiao's research lab specializes in advanced thin film materials and plasma-based nanofabrication, with a focus on controlling the microstructure, stress evolution, and magnetic properties of L10-ordered FePt films for high-density magnetic storage applications. The lab investigates rapid thermal annealing and stress engineering to manipulate crystallographic texture and phase transformation kinetics, while also exploring novel plasma etching processes—particularly at cryogenic temperatures—for sub-nanoscale patterning of dielectrics and nitrides. Their work bridges materials synthesis, in-situ stress monitoring, and plasma chemistry to enable next-generation semiconductor device fabrication.
Figures are computed from collected data and may differ slightly.
Initial stress (σi) of a room-temperature deposited FePt films was manipulated to study the order-disorder transformation. We observed that, while σi was increased from −1.01 (compressive) to 0.18 GPa (tensile), the phase transformation activation energy decreased from 0.387 to 0.23 eV/atom. This causes a reduction in ordering temperature of about 100 °C. We also found that densification induces an increase in tensile stress of about 1 GPa before ordering. In the films with small σi, strong tens
Roles of rapid thermal annealing (RTA) on the evolution of crystallographic anisotropy of single-layered FePt films have been characterized. We observed a huge biaxial tensile stress of 2.18 GPa induced with increasing heating rate from 0.5 to 40 K/s. The result is a transition of orientation from (111) to perfect (001) texture. The later then degrades at heating rates ≥80 K/s due to morphological variation. The advantages of RTA are to induce tensile stress by densification reaction within a ve
Single-layered FePt thin films were deposited on glass substrates and subsequently annealed at 800 °C for various times in a rapid thermal annealing (RTA) furnace. Near-fully-L10-ordered FePt films were obtained after RTA. The accumulation of the intrinsic tensile stress is mainly contributed by the densification reaction, which leads to the development of (001) preferred orientation. The relief of the tensile stress predominantly stems from the microstructural variation (from continuous to inte
Manufacturing semiconductor devices requires advanced patterning technologies, including reactive ion etching (RIE) based on the synergistic interactions between ions and etch gas. However, these interactions weaken as devices continuously scale down to sub-nanoscale, primarily attributed to the diminished transport of radicals and ions into the small features. This leads to a significant decrease in etch rate (ER). Here, a novel synergistic interaction involving ions, surface-adsorbed chemistri
Cyclic atomic layer etching (ALE) of SiN with high selectivity to SiO<sub>2</sub>, utilizing a hydrofluorocarbon deposition followed by exposure to hydrogen plasma, is presented. The surface reaction mechanism and etching behavior were investigated with in situ attenuated total reflectance Fourier transformation infrared spectroscopy (ATR-FTIR) and spectroscopic ellipsometry. In the deposition step, the hydrofluorocarbon film was deposited on top of the SiN films using the CF<sub>4</sub>/H<sub>2
The etch characteristics of SiN films using CF4/H2 and HF/H2 plasmas were investigated in a dual-frequency capacitively coupled plasma reactor with increasing an H2 percentage from 5 to 34%. The etch rate decreased by 35% in CF4/H2 and 10% in HF/H2. F density, measured by optical emission actinometry, decreased by approximately 70% in both plasmas, but it alone could not explain the etch rate reduction. Surface analysis revealed the formation of (NH4)2SiF6, an ammonia fluorosilicate (AFS) phase,
The surface conductivity influences the etched pattern profiles in the plasma process. In the dielectric film etching, it is vital to reduce the charging build-up, which bends the trajectory of incoming ions for highly anisotropic etching. A significant increase in surface electric conductivity of SiO2 films was observed when exposed to down-flow plasmas containing hydrogen fluoride (HF) at cryogenic temperature (−60 °C). This phenomenon can be attributed to two factors: (i) the absorption of HF
Abstract The dependences of etching characteristics on substrate temperature ( T s , from –20 to 50°C) of the plasma‐enhanced chemical vapor deposition (PECVD) SiN films (PE‐SiN) and low‐pressure chemical vapor deposition (LPCVD) SiN films (LP‐SiN) with CF 4 /H 2 plasma were investigated. The Fourier‐transform infrared spectroscopy shows that both film types were N–H bond‐rich films, but in different hydrogen contents (PE‐SiN 22.7 at% and LP‐SiN 3.8 at%) from the Rutherford backscattering spectr
With the increasing interest in dry etching of silicon nitride, utilization of hydrogen-contained fluorocarbon plasma has become one of the most important processes in manufacturing advanced semiconductor devices. The correlation between hydrogen-contained molecules from the plasmas and hydrogen atoms inside the SiN plays a crucial role in etching behavior. In this work, the influences of plasmas (CF4/D2 and CF4/H2) and substrate temperature (Ts, from −20 to 50 °C) on etch rates (ERs) of the PEC
We have characterized the dependence of residual strain/stress on annealing process (post- and in-situ annealing) in single-layer FePt films prepared by sputtering onto amorphous glass substrates. A remarkable difference of evolutions in residual strains between post-andin-situ annealed samples was observed by Sin <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ψ method using synchrotron radiation. The onset of ordering temperature for both
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