• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.103-104
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• 2006

PRAM (Phase change Random Access Memory) is one of the most promising candidates for next generation Non-volatile Memories. The Phase change material has been researched in the field of optical data storage media. However, the characteristics required in solid state memory are quite different from optical ones. In this study, the reset current and temperature profile of PRAM cells with bottom electrode were calculated by the numerical method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.69-70
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• 2006

A detailed Investigation of cell structure and electrical characteristic in chalcogenide-based phase-change random access memory(PRAM) devices is presented. We used compound of Ge-Sb-Te material for phase-change cell. A novel bottom electrode structure and manufacture are described. We used heat radiator structure for improved reset characteristic. A resistance change measurement is performed on the test chip. From the resistance change, we could observe faster reset characteristic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.144-145
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• 2007

Phase change random access memory is one of the most promising candidates for next generation non-volatile memories. However, the high reset current is one major obstacle to develop a high density PRAM. One way of the reset current reduction is to develop the new phase change material. In this paper, to reduce the reset current for phase transition, we have investigated the effect of phase change material parameters using finite element analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.97-98
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• 2007

In this paper, we analyzed the reset current variation of PRAM device with top electrode using the 3-D finite element analysis tool. As thickness of phase change material thin film decreased, reset current caused by phase transition highly increased. Joule's heat which was generated at the contact surface of phase change material and bottom electrode of PRAM was given off through top electrode to which was transferred phase change material. As thermal conductivity of top electrode decreased, heating temperate was increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.156-157
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• 2007

For tens of years many advantages of Phase-Change Random Access Memory(PRAM) were introduced. Although the performance improved gradually, there are some portions which must be improved. So, we studied new constitution of $Ge_1Se_1Te_2$ chalcogenide material to improve phase transition characteristic. Actually, the performance properties have been improved surprisingly. However, crystallization time was as long as ever for amorphization time. We conducted this experiment in order to solve that problem by doping-Sb.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.203-204
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• 2005

PRAM (Phase change Random Access Memory) is one of the most promising candidates for next generation Non-volatile Memories. The Phase change material has been researched in the field of optical data storage media. Among the phase change materials $Ge_2Sb_2Te_5$(GST) is very well known for its high optical contrast in the state of amorphous and crystalline. However, the characteristics required in solid state memory are quite different from optical ones. In this study, the structural properties of GST thin films with composition were investigated for PRAM. The 100-nm thick GeTe and $Sb_2Te_3$ films were deposited on $SiO_2$/Si substrates by RF sputtering system. In order to characterize the crystal structure and morphology of these films, we performed x-ray diffraction (XRD) and atomic force microscopy (AFM).

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.181-182
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• 2011

Phase-change materials can be cycled by exposure to laser beam, and as a function of the pulse intensity and duration, the laser beam triggers the switching from crystalline to amorphous phase and back. In other to progress better crystallization transition and amorphization long phase-transformation data of phase-change memory (PRAM), we investigated about the effect of Sb doping and Ag ions percolating into Ge-Se-Te phase-change material. Doped Sb concentrations was determined each of 10, 20 and 30 wt%. As the Sb-doping concentration was increased, the resistivity decreased and the crystallization temperature increased. Ionization of Ag was progressed by DPSS laser (532 nm) for 1 hour. The resistivity was more decreased and the crystallization temperature was more increased in case of adding Ag layer under Sb-(Ge-Se-Te) thin film. At the every condition of thin films included Ag layer more stable states were indicated compare with just Sb-doped Ge-Se-Te thin films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.347-347
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• 2010

In other to progress better crystallization transition and long phase-transformation data of phase-change memory (PRAM), we investigated about the effect of Sb doping and Ag ions percolating into Ge-Se-Te phase-change material. Doped Sb concentrations was determined each of 10 wt%, 20 wt% and 30 wt%. As the Sb-doping concentration was increased, the resistivity decreased and the crystallization temperature increased. Ionization of Ag was progressed by DPSS laser (532 nm) for 1 hour. The resistivity was more decreased and the crystallization temperature was more increased in case of adding Ag layer under Sb-(Ge-Se-Te) thin film. At the every condition of thin films included Ag layer more stable states were indicated compare with just Sb-doped Ge-Se-Te thin films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.218-219
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• 2008

In this paper, we have investigated the phase change memory device with cell structure using three-dimensional finite element analysis tool for reducing reset current. From the simulation, the reset current of PRAM with $SiO_2$ inserting layer is greatly reduced, compared with the conventional device.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1272-1273
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• 2008

PRAM(Phase change access memory) has desirable characteristics including high speed, low cost, low power, and simple process. PRAM is based on the reversible phase transition between resistive amorphous and conductive crystalline states of chalcogenide. However, PRAM needs high reset current for operation. PRAM have to reduce reset current for high density and competitiveness. Therefore, we have investigated the reset current of PRAM with top electrode contact hole size using 3-D finite element analysis tool in this paper.