非揮發性記憶體應用-鈦/氧化鋅奈米帶/鈦架構下之電阻轉換特性研究

Abstract

本篇研究論文藉由汽相催化轉換再凝結之製程,沉積出單晶系的氧化鋅奈米帶(ZnO NB)探討其電阻轉換現象，藉由量測氧化鋅奈米帶的電流(I)-電壓(V)關係曲線，顯示出在以往體狀薄膜電容架構下的單極性電阻轉換器所無法顯現出的某些受關注且特殊的特性；首先觀察到的是，相較重置電壓而言，得到較小的置入電壓以及高電阻態(HRS)與低電阻態(LRS)的電阻轉換率為4~5 個階級，其中，高電阻態、低電阻態可藉由外加偏壓調節。我們以空間電荷極限電流理論與提供 載子傳輸位置的氧缺陷相結合，提出主要載子傳輸機制與電阻轉換的機制。藉由I-V 曲線中，線性區域( ∝V)與二次方區域( ∝V2)求得的交點電壓可知，體狀薄膜結構與長寬比例顯著的氧化鋅奈米帶結構差異極大。

The phenomenon of resistive switching in single crystal of zinc oxide nanobelt(ZnO NB) fabricated by catalytically activated vapor phase transport and condensation deposition process has been investigated. From measuring the current (I)-voltage (V) curve, the ZnO NB reveals some interesting and distinctive characteristics not found in previous unipolar resistive switching behavior of bulk film capacitors. The smaller set voltage compared to reset voltage is first observedand the resistance ratio of HRS to LRS is in the range of 4-5 orders. Both high resistance state (HRS) and low resistance state (LRS) is tunable by means of applied voltage. The dominant carrier transport and resistive switching mechanism was elucidated using theory of space-charge-limited current incorporated with oxygen vacancy for carrier transport site. High aspect ratio factor of ZnO NB different from bulk film is obtained from crossover voltage between liner region and quadratic region of I-V curve.