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High Contact Resistivity Enabling Low‐Energy Operation in Cr 2 Ge 2 Te 6 ‐Based Phase‐Change Random Access Memory
Author(s) -
Hatayama Shogo,
Abe Yasunori,
Ando Daisuke,
Sutou Yuji
Publication year - 2021
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000392
Subject(s) - amorphous solid , electrode , materials science , phase change memory , electrical resistivity and conductivity , contact resistance , optoelectronics , work function , semiconductor , phase (matter) , amorphous semiconductors , random access memory , electrical engineering , nanotechnology , metallurgy , metal , crystallography , computer science , chemistry , silicon , engineering , layer (electronics) , organic chemistry , computer hardware
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. Cr 2 Ge 2 Te 6 (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 LaB 6 electrode. The resistance of the CrGT‐based device with a LaB 6 electrode (LaB 6 device) is three or four orders of magnitude greater than that of a device with a W electrode (W device). The LaB 6 device is indicated to require much smaller operation energy than the W device.