New Type Of Resistance Change Material Preparation Technology And Its Mechanism Of Resistance Change Is Studied

Resistive random access memory (RRAM) is considered as one of the most promising candidates for the next generation of high-density non-volatile memory, owing to its simple fabricating process and compatibility with complementary metal oxide semiconductor (CMOS) technology. The resistive switching behavior has been observed in a number of transition metal oxides (TM-oxides), such as NiO, TiO2, HfO2, CuxO, ZnO and SrTiO3, and solid electrolytes, such as GeSe, silicon, and some of organics. However, resistive switching characteristics and physical mechanism in nitrides has not been fully studied yet. Some nitrides such as copper nitride have similar electrical properties to TM-oxides, which is considered as potential new resistive material. We creatively present another type of variable-resistive compound semiconductor:copper nitride prepared by plasma-immersion ion implantation (PⅢ) as well as DC magnetron sputtering and its working mechanism of resistive switching is discussed based on our results.Copper nitride film prepared by plasma-immersion ion implantation (PⅢ) is demonstrated to exhibit reversible resistance variance character. By forming a gradually distributed nitrogen concentration in the Cu-nitride film, the nitride-based memory devices show bipolar nature with a low operation voltage and forming-free characteristics. The fitting results for the electrical measurements show that the resistance in HRS follows trap-controlled space-charge-limited conduction (SCLC) model, which is not the major reason of current sharply increasing.The bipolar switching behavior is attributed to the formation and rupture of conductive filaments within a cycle, which is confirmed by spreading-resistance images of a conducting atomic force microscope.Resistive random access memory (RRAM) devices are made by copper nitride films prepared by DC magnetron sputtering. After a forming process, the CuxN-based RRAM devices show bipolar character with low operation voltage, better endurance and uniformity. The fitting results for the electrical measurements and the conducting atomic force microscope (CAFM) analysis indicate that resistive switching mechanism is consistent with the formation and rupture of conducting filaments. Moreover, the conducting filament density of this device in LRS could be calculated as high as about40×40nm2/filament, providing a promising potential in scaling for manufacturing high-density RRAM device using this type of nitride compound.Pt/CuxN/Pt cells shows quite similar resistive properties to that of Ni/CuxN/Ni cells, which implies that the electrochemical metallization mechanism (ECM) does not work for this kind of device. Based on X-ray photoelectron spectroscopy (XPS) analysis, semiconducting Cu3N phase and metallic Cu4N phase coexist in the copper nitride film and Cu3N phase could change into Cu4N phase by inserting a Cu atom into the body center of Cu3N anti-ReO3structure. We propose that local conducting filaments might be formed by interconnection of the metallic phases by migration of Cu ions under a bias voltage.