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Hyokyung Bahn
- The Journal of the Institute of Internet, Broadcasting and Communication
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- v.24 no.4
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- pp.29-33
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- 2024
Recent advancements in mobile apps have led to continuously increasing memory demands on smartphone systems. Unlike desktops, which use swap functions to backup the entire memory footprint to storage when memory space is exhausted, smartphones terminate apps and lose significant context. This occurs because large-scale I/O operations to flash memory cause severe delays when swap is enabled on smartphones. This paper discusses how efficient memory management can be performed by using eMRAM, which is faster in write operations than flash memory, as the swap area in mobile systems. Considering the characteristics of backup storage (i.e., flash memory for the file system and eMRAM for the swap areas) as well as the reference characteristics of each page, we demonstrate that the proposed memory allocation and reclamation policies can improve the smartphone's I/O performance by an average of 15%.
https://doi.org/10.7236/JIIBC.2024.24.4.29 인용 PDF HTML

Lee, Jeong-Won;Shin, Sung-Chul;Kim, Sang-Koog
- Proceedings of the Korean Magnestics Society Conference
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- 2002.12a
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- pp.188-189
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- 2002
One of the current goals in memory device developments is to realize a nonvolatile memory, i.e., the stored information maintains even when the power is turned off. The representative candidates for nonvolatile memories are magnetic random access memory (MRAM) and ferroelectric random access memory (FRAM). In order to achieve a high density memory in MRAM device, the external magnetic field should be localized in a tiny cell to control the direction of spontaneous magnetization. (omitted)
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Xiao, Y.B.;Kim, E.H.;Kong, S.M.;Chung, C.W.
- Proceedings of the Korean Vacuum Society Conference
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- 2010.02a
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- pp.213-213
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- 2010
Magnetic random access memory (MRAM), based on magnetic tunnel junction (MTJ) and CMOS, is one of the best semiconductor memories because it can provide nonvolatility, fast access time, unlimited read/write endurance, low operating voltage and high storage density. For the realization of high density MRAM, the etching of MTJ stack with good properties is one of a key process. Recently, there has been great interest in the MTJ stack using MgO as barrier layer for its huge room temperature MR ratio. The use of MgO barrier layer will undoubtedly accelerate the development of MTJ stack for MRAM. In this study, high-density plasma reactive ion etching of MgO films was investigated in an inductively coupled plasma of $Cl_2$/Ar gas mixes. The etch rate, etch selectivity and etch profile of this magnetic film were examined on vary gas concentration. As the $Cl_2$ gas concentration increased, the etch rate of MgO monotonously decreased and etch slop was slanted. The effective of etch parameters including coil rf power, dc-bais voltage, and gas pressure on the etch profile of MgO thin film was explored, At high coil rf power, high dc-bais voltage, low gas pressure, the etching of MgO displayed better etch profiles. Finally, the clean and vertical etch sidewall of MgO films was achieved using $Cl_2$/Ar plasma at the optimized etch conditions.
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Xiao, Y.B.;Kim, E.H.;Kong, S.M.;Chung, C.W.
- Proceedings of the Korean Vacuum Society Conference
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- 2010.02a
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- pp.233-233
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- 2010
Magnetic random access memory (MRAM), based on magnetic tunnel junction (MTJ) and CMOS, is a prominent candidate among prospective semiconductor memories because it can provide nonvolatility, fast access time, unlimited read/write endurance, low operating voltage and high storage density. The etching of MTJ stack with good properties is one of a key process for the realization of high density MRAM. In order to achieve high quality MTJ stack, the use of CoFeB and IrMn magnetic films as free layers was proposed. In this study, inductively coupled plasma reactive ion etching of CoFeB and IrMn thin films masked with Ti hard mask was investigated in a $Cl_2$/Ar gas mix. The etch rate of CoFeB and IrMn films were examined on varying $Cl_2$ gas concentration. As the $Cl_2$ gas increased, the etch rate monotonously decreased. The effective of etch parameters including coil rf power, dc-bais voltage, and gas pressure on the etch profile of CoFeB and IrMn thin film was explored, At high coil rf power, high dc-bais voltage, low gas pressure, the etching of CoFeB and IrMn displayed better etch profiles. Finally, the clean and vertical etch sidewall of CoFeB and IrMn free layers can be achieved by means of thin Ti hard mask in a $Cl_2$/Ar plasma at the optimized condition.
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