Fabrication and Investigation of InxGa1-xO Insulator for Non-volatile RRAM

• Main Authors: Yong-ZheLin, 林永哲
• Other Authors: Shoou-Jinn Chang
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/33x2r6

碩士 === 國立成功大學 === 微電子工程研究所 === 107 === Fabrication and Investigation of InxGa1-xO Insulator for Non-volatile RRAM Yong-Zhe Lin* Shoou-Jinn Chang** Institute of Microelectronic ＆ Department of Electrical Engineering National Cheng Kung University Abstract In this thesis, InxGa1-xO is used as the resistive switching layer of non-volatile random-access memory. This is because indium atoms and gallium atoms are always used as the materials of transistors, sensors and solar cells, and electrical property can be modulated by changing the ratio of indium atoms to gallium atoms. First, Pt, Ti and Al are used as the top electrode and Pt is used as bottom electrode. We investigated the manufacturing process and electrical property of the RRAM devices. Because the three top electrodes has different chemical properties, transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy (EDS) are used to analyze the interface of the top electrode and the resistive switching layer and confirm the impact of the top electrode on the electrical properties. Moreover, we research Pt/InxGa1-xO/Pt RRAM, Ti/InxGa1-xO/Pt RRAM and Al/InxGa1-xO/Pt RRAM and investigate the impact of the In/Ga ratio on the electrical properties of the RRAM devices. As the results demonstrate, at room temperature, the fabricated devices can switch over 100 times and maintain high resistance state (HRS) and low resistance state (LRS) for 10000 seconds respectively in the bipolar switching mode with 100mV reading voltage. Then, Al/Ga2O3/Pt RRAM is improved specially because its best performance among all the devices. The oxygen vacancies are diminished by increasing the oxygen partial pressure of RF sputtering system. As the results demonstrate, the resistive switching performance will be better if the oxygen vacancies are diminished appropriately. At room temperature, the Al/Ga2O3/Pt RRAM device can switch over 2000 times and maintain high resistance state and low resistance state for 10000 seconds respectively in the bipolar switching mode with 100mV reading voltage. Finally, we use Al as the top electrode, Pt as the bottom electrode and from the bottom electrode to the top electrode, Ga2O3, In0.1Ga0.9O, In0.4Ga0.6O, In0.9Ga0.1O and In2O3 as the resistive switching layer to fabricate the penta-layer gradual binary oxide RRAM (Gradual RRAM). We find that the resistive switching performance is improved due to the gradient of the mobility and concentration gradient of the oxygen vacancies. It means that not only the electrode and the material of the resistive switching layer have impact on the performance of RRAM but also the structure of gradual binary oxide is one of the methods to improve the performance of RRAM. Key words: non-volatile RRAM, InxGa1-xO, In2O3, Ga2O3 Author* Advisors**