鎳/氧化鉿/氮化鈦結構的電阻式記憶體及其熱處理效應

Abstract

在本論文中，我們使用鎳、非化學當量的氧化鉿和氮化鈦的金屬-氧化物-金屬結構來展示電阻式記憶體的特性。可以觀察到重覆性的電阻值轉換而且平均的電阻比例大於100。經過氬氣退火的氧化鉿薄膜展現出大電流操作的特性，藉由X光繞射分析觀測到氧化鉿薄膜已經結晶，這可能是造成大電流操作的原因。為了降低功率消耗，我們對氧化鉿進行氧退火並且使用細絲理論來解釋量測到的數據。量測結果顯示：比起沒有氧退火的試片而言，氧退火過的試片其電流和功率消耗都大約小10倍。經過氧退火製程後，操作電壓並沒有很顯著的增加，而且耐用度也稍微改善。除此之外，資料保留特性和非破壞性讀取也在本讑文中被測試。我們的研究顯示：退火過的鎳/氧化鉿/氮化鈦的電阻式記憶體是很有希望被應用在低功率消耗的非揮發性記憶體。

In this thesis, we used metal-oxide-metal (MOM) structure of nickel (Ni), non-stoichiometric hafnium oxide (HfOx), and titanium nitride (TiN) to demonstrate RRAM characteristics. Voltage-induced resistance switching is repeatedly observed in the Ni/HfOx/TiN device with average resistance ratio greater than 100. The HfOx film which is annealed in Ar ambient exhibits large current operation. It is probably due to crystallization of HfOx film by X-Ray Diffraction (XRD) result. In order to reduce power dissipation, HfOx is oxygen annealed and we use filamentary model to explain the measured data. Measurement result shows that all operation current and power are smaller about 10 times than the sample which is not annealed in O2 ambient. Operation voltage is not elevated noticeably and endurance is slightly improved after oxygen annealing process. Besides, data retention and non-destructive readout are tested in this thesis. Our study shows that the annealed Ni/HfOx/TiN RRAM is a promising candidate for low power nonvolatile memory applications.