本研究利用雙晶氧化銅奈米線製作電阻式開關元件，並量測出兩種不同元件型態，分別為單穩態電阻式開關及雙穩態電阻式開關，其中雙穩態電阻式開關即電阻式記憶體。為觀察該二種元件型態，吾人首先利用電子束微影技術和PECS系統為元件鍍製不同厚度之電極，並於室溫量測元件，而該元件結構為金屬/氧化銅奈米線/金屬之電容式結構。當該電容結構之金屬電極厚度≦60 nm時，元件特性呈單穩態電阻式開關(threshold resistive switching)；然而當電極厚度達100 nm時，元件特性便呈雙穩態電阻式開關(memory resistive switching)。此外，若對特性呈單穩態電阻式開關之元件於量測的過程中降低通過元件之限制電流大小，自10-6A降至10-7A，其元件特性便轉變為雙穩態電阻式開關。而這些有趣的現象和RS元件內部熱消散的能力有關，不論於元件操作時提高限制電流大小或是減少元件電極厚度，皆造成無法有效消散電流通過元件所產生的焦耳熱，進而使元件內部的導電通道無法穩定存在。為更進一步探討導電通道狀態對於元件特性的影響，吾人便對具單穩態特性之元件施予脈衝，脈衝電壓大小為2 V，脈衝持續時間為1至10 msec，元件特性由單穩態轉換為雙穩態；接著吾人對元件低阻態(ON state)量測低溫電性，其結果顯示導電通道的導電特性如同金屬。該現象意味著施予脈衝能夠聚集氧空缺於導電通道斷裂區域，並形成新的通道，而上述的工作不僅提供導電通道形成機制，也提出單穩態和雙穩態電阻式開關間之關係。最後吾人利用FIB將RS元件製作成TEM試片，試圖找尋元件內部所產生的通道。

This study investigated two types of reversible resistive switching behaviors in bi-crystal CuO nanowires. One is mono-stable resistive switching (threshold resistive switching) behavior, and the other is bi-stable resistive switching (memory resistive switching). First, We utilized electron beam lithography technique and PECS deposition system to fabricate single nanowire reversible resistive switching device. The single NW RS behaviors were further investigated by varying electrode thickness in the metal/CuO/metal capacitor structure at RT. The threshold RS behavior dominated with electrode thickness ≦ 60 nm, while the memory RS behavior dominated when the electrode thickness was around 100 nm. In addition, the phenomenon of memory RS was also observed for the device with electrode thickness = 30 nm by decreasing the current compliance value from 10-6 A to 10-7 A. These interesting phenomena might be related to heat dissipation. The thinner the electrodes, the lesser the dissipation rate of Joule heat. Thus, this resulted in less stable conductive channels. Moreover, we also observed that memory RS behavior recovers from threshold RS by applying a pulse at 2V for a duration of 1 to 10 msec, and the metallic behavior existed in ON state of RS device by temperature dependent I-V measurement. The phenomenon suggests that oxygen ions would migrate in electric field and form new conductive channels at the original broken channel in threshold RS device. These work provided more understanding on the interplay between threshold RS and memory RS effects. Finally, we tried to discover the conductive channels at RS device by technique of FIB and TEM.

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