Carbon-doped Ge2Sb2Te5 phase change material: A candidate for high-density phase change memory application

Abstract

Carbon-doped Ge2Sb2Te5 material is proposed for high-density phase-change memories. The carbon doping effects on electrical and structural properties of Ge2Sb2Te5 are studied by in situ resistance and x-ray diffraction measurements as well as optical spectroscopy. C atoms are found to significantly enhance the thermal stability of amorphous Ge2Sb2Te5 by increasing the degree of disorder of the amorphous phase. The reversible electrical switching capability of the phase-change memory cells is improved in terms of power consumption with carbon addition. The endurance of ∼2.1 × 104 cycles suggests that C-doped Ge2Sb2Te5 film will be a potential phase-change material for high-density storage application.

Phase-change properties of GeSbTe thin films deposited by plasma-enchanced atomic layer depositon

“…The measured set speed of the ALDdeposited GST films is slower than that of PVD-deposited GST films, which is supposedly due to the impurities. Especially N, C impurities in ALD-deposited GST films are known to increase the crystallization temperature and reduce the crystallization speed of the GST films [17,18].…”

Carbon doping induced Ge local structure change in as-deposited Ge2Sb2Te5 film by EXAFS and Raman spectrum

“…22 Therefore, the higher carbon content doped GST film will have a higher bandgap and initial state resistance. 23 Meanwhile, there is a significant difference in the cooling curve between GST, C5.5-GST and C6.7-GST. As can be seen from Fig.…”

Sb52Se36Te12 material with high-temperature data retention coupled with rapid crystallization speed for phase change application

“…However, GST has a low crystallization temperature (about 150 C [6,7]), which leads to poor data retention just sufficient for some consumer applications (85 C for 10 years [8,9]), far away from the requirements of automotive system (120 C for10 years [10]). Moreover, the thermal cross-talk between neighboring cells which will be more severe in high-density memory arrays requires higher stability of the amorphous phase to boost data retention performances of PCM [1]. What is more, there are also other issues such as the high reset current and slow speed of amorphous-to-crystalline phase transition that need to be addressed [10][11][12].…”

“…As is known, phase change memory (PCM) is drawing much attention as a next generation substitute for rewritable nonvolatile memory due to its advantages like high speed, high density, large cycling endurance, good compatibility with standard complementary metal-oxide-semiconductor (CMOS) process [1][2][3]. The main principle of PCM is the rapid and reversible phase change between amorphous [high resistivity (RESET) state] and crystalline [low resistivity (SET) state] states induced by electrical pulses.…”