Static information storage and retrieval – Read only systems – Resistive
Reexamination Certificate
2002-10-25
2004-12-28
Dinh, Son T. (Department: 2824)
Static information storage and retrieval
Read only systems
Resistive
C365S163000, C257S002000, C257S004000
Reexamination Certificate
active
06836423
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to programmable memory devices.
2. Background
Typical memory applications include dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read only memory (EPROM), and electrically erasable programmable read only memory (EEPROM).
Solid state memory devices typically employ micro-electronic circuit elements for each memory bit (e.g., one to four transistors per bit) in memory applications. Since one or more electronic circuit elements are required for each memory bit, these devices may consume considerable chip “real estate” to store a bit of information, which limits the density of a memory chip. The primary “non-volatile” memory element of these devices, such as an EEPROM, typically employ a floating gate field effect transistor device that has limited re-programmability and which holds a charge on the gate of field effect transistor to store each memory bit. These classes of memory devices are also relatively slow to program.
Phase change memory devices use phase change materials, i.e., materials that can be electrically switched between a generally amorphous and a generally crystalline state, for electronic memory application. One type of memory element originally developed by Energy Conversion Devices, Inc. of Troy, Mich. utilizes a phase change material that can be, in one application, electrically switched between a structural state of generally amorphous and generally crystalline local order or between different detectable states of local order across the entire spectrum between completely amorphous and completely crystalline states. Typical materials suitable for such application include those utilizing various chalcogenide elements. These electrical memory devices typically do not use field effect transistor devices, but comprise, in the electrical context, a monolithic body of thin film chalcogenide material. As a result, very little chip real estate is required to store a bit of information, thereby providing for inherently high density memory chips. The state change materials are also truly non-volatile in that, when set in either a crystalline, semi-crystalline, amorphous, or semi-amorphous state representing a resistance value, that value is retained until reset as that value represents a physical state of the material (e.g., crystalline or amorphous). Thus, phase change memory materials represent a significant improvement in non-volatile memory.
One characteristic of memory devices is the need for addressing lines, such as column and row lines to program and read a memory device. In currently conceived phase change memory devices a column line and a row line address a distinct cell formed over a substrate. The Energy Conversion Devices, Inc. structure comprises a double level metal cell structure with the memory element constituting a cell composed of a volume of memory material, an electrode between a row line and the memory material, and an upper electrode overlying the memory material. The cell is coupled to a column line by a via. The via-column line contact requires the cell size of the memory device to be increased to support the contact pitch. It would be desirable in terms of reducing fabrication complexity, cost, and memory cell size to modify the addressing line configuration of a memory cell device.
REFERENCES:
patent: 5912839 (1999-06-01), Ovshinsky et al.
patent: 6141241 (2000-10-01), Ovshinsky et al.
patent: 6339544 (2002-01-01), Chiang et al.
patent: 0 144 604 (1985-06-01), None
patent: WO 96/41380 (1996-12-01), None
Hwang, Y.N., Hong, J.S., Lee, S.H., Ahn, S.J., Jeong, G.T., Koh, G.H., Kim, H.J., Jeong, W.C., Lee, S.Y., Park, J.H., Ryoo, K.C.., Horii, H., Ha, Y.H., Yi, J.H., Cho, W.Y., Kim, Y.T., Lee, K.H., Joo, S.H., Park, S.O., Jeong, U.I., Jeong, H.S. and Kim, Kinam, “Completely CMOS-Compatible Phase-Change Nonvolatile RAM Using NMOS Cell Transistors,” presented at 2003 19thIEEE Non-Volatile Semiconductor Memory Workshop, Monterey, California, Feb. 26-20, 2003.
Ha, Y.H., Yi, J.H., Horii, H., Park, J.H., Joo, S.H., Park, S.O., Chung U-In and Moon J.T., “An Edge Contact Type Cell for Phase Change RAM Featuring Very Low Power Consumption,” presented at IEEE 2003 Symposium on VLSI Technology, Kyoto, Japan, Jun. 12-14, 2003.
Hwang, Y.N., Hong, J.S., Lee, S.H., Ahn, S.J., Jeong, G.T., Koh, G.H., Oh, J.H., Kim, H.J., Jeong, W.C., Lee, S.Y., Park, J.H., Ryoo, K.C., Horii, H., Ha, Y.H., Yi, J.H., Cho, W.Y., Kim, Y.T., Lee, K.H., Joo, S.H., Park, S.O., Chung, U.I., Jeong, H.S. and Kim, Kinam, “Full Integration and Reliability Evaluation of Phase-change RAM Based on 0.24 mm-CMOS Technologies,” presented at IEEE 2003 Symposium on VLSI Technology, Kyoto, Japan, Jun. 12-14, 2003.
Horii, H., Yi, J.H., Park, J.H., Ha, Y.H., Baek, I.G., Park, S.O., Hwang, Y.N., Lee, S.H., Kim, Y.T., Lee, K.H., Chung, U-In and Moon, J.T., “A Novel Cell Technology Using N-doped GeSbTe Films for Phase Change RAM,”presented at IEEE 2003 Symposium on VLSI Technology, Kyoto, Japan, Jun. 12-14, 2003.
Gill Manzur
Lowrey Tyler A.
Dinh Son T.
Ovonyx Inc.
Trop Pruner & Hu P.C.
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