本研究利用高熵合金的核心效應設計非晶質高熵合金薄膜，以期具有優良的熱穩定性。這些成功開發出合金系統有Ge0.5NbTaTiZr、GeNbTaTiZr、BNbTaTiZr與SiNbTaTiZr，其非晶結構分別在700 °C、750 °C、800 °C與850 °C下進行 1小時的真空退火後仍能維持。對如此傑出熱穩定性的成因，本研究以高混合熵(熱力學因素)，顯著的原子尺寸差異(拓樸學因素)與遲緩擴散效應(動力學因素)加以討論。此外，有較低混合熵與原子尺寸差異的四元等莫耳NbTaTiZr亦被開發作為對照組，用以與前述五元薄膜比較熱穩定性。
因為非晶薄膜在一些特殊環境應用時會考量到機械性質與電性，本研究也對設計之四元與五元薄膜量測並分析這兩項特性。例如在冷熱環境中需要應用高電阻合金的狀況下，合金需具有低的電阻溫度係數。與傳統非晶質合金薄膜的硬度比較，本研究中四元合金薄膜的硬度可謂與其旗鼓相當，而五元合金薄膜的硬度則較高。所有設計的非晶高熵合金薄膜都有高電阻與小且負的電阻溫度係數。由上述結果可知，本研究開發之非晶質高熵合金薄膜擁有很大的應用潛力。這些結果也進一步闡明所使用的設計策略十分有效。

Core effects of high entropy alloys (HEAs) are utilized to design high entropy alloy thin films (HEATFs) with excellent thermal stability of amorphous structures. These HEATFs are Ge0.5NbTaTiZr, GeNbTaTiZr, BNbTaTiZr and SiNbTaTiZr. After one hour annealing in high vacuum condition, the highest experimental temperature at which their amorphous structure retained are 700 oC, 750 oC, 800 oC and 850 oC, respectively. Thermodynamic, topological and kinetic factors governing outstanding thermal stability of quinary HEATFs, are discussed via high entropy effect, atomic size differences and sluggish diffusion phenomena. By contrast, we set quaternary equiatomic NbTaTiZr alloy film as a reference, in which high entropy and atomic size difference are lesser than aforementioned quinary HEATFs, so as to compare and discuss their thermal stability.
Since mechanical and electrical properties of amorphous thin films are often important in special applications (e.g. high resistivity and low temperature coefficient of resistivity (TCR) for cold and hot environments), mechanical and electrical properties of quaternary and quinary HEATFs were investigated. As compared to the hardness of conventional amorphous metal thin films, those of quaternary and quinary HEATFs are comparable and higher, respectively. All HEATFs display high resistivities and small negative temperature coefficients of resistivity. In summary, these results verify that the design strategy is valid and further demonstrates that the designed HEATFs are potential for special application.

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