High Contact Resistivity Enabling Low‐Energy Operation in Cr2Ge2Te6‐Based Phase‐Change Random Access Memory. Issue 3 (2nd October 2020)

• Record Type: Journal Article
• Authors: Hatayama, Shogo; Abe, Yasunori; Ando, Daisuke; Sutou, Yuji
• Is Part Of: Physica status solidi. Volume 15:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-02
• Subjects: contact resistivity -- Cr–Ge–Te -- inverse resistance change -- low operation energy -- phase change memory; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202000392
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : A phase‐change material (PCM) exhibiting a significant difference in resistance between the amorphous and crystalline phases can be used for phase‐change random access memory (PCRAM). Reduction of the energy to operate is one of the major challenges in PCRAM technology. One strategy for energy reduction is to increase the resistance of the memory device in the crystalline state of the PCM. Cr2 Ge2 Te6 (CrGT) shows p‐type semiconductor characteristics in both the amorphous and crystalline phases. A CrGT‐based memory device shows a contact resistance–dominant behavior, suggesting that the resistance of a CrGT‐based memory device can be increased by changing the electrode material. The contact resistivity ( ρ c ) of a CrGT/electrode increases with a decrease in the work function of the electrode material in both amorphous and crystalline phases, as with general p‐type semiconductor materials. The highest ρ c is observed for a LaB6 electrode. The resistance of the CrGT‐based device with a LaB6 electrode (LaB6 device) is three or four orders of magnitude greater than that of a device with a W electrode (W device). The LaB6 device is indicated to require much smaller operation energy than the W device. Abstract : The resistance of a Cr2 Ge2 Te6 (CrGT)‐based phase‐change random access memory (PCRAM) is demonstrated to be tunable by changing the electrode material. A high contact resistivity is observed for the Cr2 Ge2 Te6 /LaB6 interface. By changing the electrode material from the conventional W to LaB6, a drastic increase in the device resistance is achieved.