16:00 〜 16:15
▲ [20p-E304-9] Bidirectional and Self-selective Characteristics of PN Diode Based N-doped Cr2Ge2Te6 Phase Change Materials
キーワード：Phase change material, selector, pn doide
To achieve a higher storage density of PCRAM, one of the most critical problem in this 3D array structure is to inhibit the sneak current to the unwanted cell, which will cause poor read accuracy and high power consumption. Regarding the sneak current problem, many groups have reported several types of memory structure, such as the serially connected one selector/one memory configuration, to achieve high-level integration of PCRAM. The selector includes several types such as Si-based or oxide-based diodes, the ovonic threshold switch (OTS), and mixed electronic and ionic conduction (MIEC). However, the complexity of the fabrication process and performance degradation at high current or temperature stress make them hard to be mass manufactured and commercialized. Simple self-selected memory cell based on self-rectifying I-V characteristics is another selector type that has been widely investigated in metal oxide resistive RAM, for example, a Ti/TiO2/Pt metal-insulator-metal sandwich structure. Nevertheless, there is a few researches related to self-selector have been done in the field of PCRAM because conventional phase change materials have a metallic-like nature crystalline phase, which is difficult to form a non-linear electrical behavior with a semiconductor layer or a metal electrode. Interestingly, the new phase change material N-doped Cr2Ge2Te6 (NCrGT) exhibits a p-type semiconductor property in both amorphous and crystalline phase. Therefore, in this study, we proposed a hybrid diode configuration composed of n-type InGaZnO4 (IGZO) and p-type NCrGT pn junction and NCrGT/W Schottky junction which enables a bi-directional selector behavior.