The 80th JSAP Autumn Meeting 2019

Presentation information

Oral presentation

16 Amorphous and Microcrystalline Materials » 16.1 Fundamental properties, evaluation, process and devices in disordered materials

[20p-E304-1~13] 16.1 Fundamental properties, evaluation, process and devices in disordered materials

Fri. Sep 20, 2019 1:45 PM - 5:15 PM E304 (E304)

Kenji Shinozaki(AIST), Tamihiro Gotoh(Gunma Univ.), Toshihiro Nakaoka(Sophia Univ.)

4:00 PM - 4:15 PM

[20p-E304-9] Bidirectional and Self-selective Characteristics of PN Diode Based N-doped Cr2Ge2Te6 Phase Change Materials

〇(D)YI SHUANG1, Shogo Hatayama1, Jun Seop An2, Ando Daisuke1, Yun Heub Song2, Yuji Sutou1 (1.Tohoku Univ., 2.Hanyang Univ.)

Keywords: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.