Multi-bit memory device having resistive material layers as storage node and methods of manufacturing and operating the same
First Claim
1. A phase change memory device including a substrate, a transistor formed on the substrate, and a storage node coupled to the transistor, wherein the storage node comprises:
- a lower electrode connected to the substrate;
a first phase change layer formed on the lower electrode and having a first minimum resistance and a first maximum resistance based on the application of a first write voltage;
a first barrier layer overlying the first phase change layer and constituting an insulating layer;
a second phase change layer overlying the first barrier layer and having a second minimum resistance and a second maximum resistance based on the application of a second write voltage, which is different from the first write voltage; and
an upper electrode formed on the second phase change layer,wherein the first barrier layer has a lower resistance than the first and second phase change layers and is thin enough to permit the tunneling of electrons.
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Abstract
Provided are a multi-bit memory device having resistive material layers as a storage node, and methods of manufacturing and operating the same. The memory device includes a substrate, a transistor formed on the substrate, and a storage node coupled to the transistor, wherein the storage node includes: a lower electrode connected to the substrate; a first phase change layer formed on the lower electrode; a first barrier layer overlying the first phase change layer; a second phase change layer overlying the first barrier layer; and an upper electrode formed on the second phase change layer.
48 Citations
21 Claims
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1. A phase change memory device including a substrate, a transistor formed on the substrate, and a storage node coupled to the transistor, wherein the storage node comprises:
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a lower electrode connected to the substrate; a first phase change layer formed on the lower electrode and having a first minimum resistance and a first maximum resistance based on the application of a first write voltage; a first barrier layer overlying the first phase change layer and constituting an insulating layer; a second phase change layer overlying the first barrier layer and having a second minimum resistance and a second maximum resistance based on the application of a second write voltage, which is different from the first write voltage; and an upper electrode formed on the second phase change layer, wherein the first barrier layer has a lower resistance than the first and second phase change layers and is thin enough to permit the tunneling of electrons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A phase change memory device including a substrate, a transistor formed on the substrate, and a storage node coupled to the transistor, wherein the storage node comprises:
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a lower electrode connected to the substrate; a first phase change layer formed on the lower electrode and having a first minimum resistance and a first maximum resistance based on the application of a first write voltage; a first barrier layer overlying the first phase change layer; a second phase change layer overlying the first barrier layer and having a second minimum resistance and a second maximum resistance based on the application of a second write voltage, which is different from the first write voltage; an upper electrode formed on the second phase change layer; and a dielectric layer that is formed between the second phase change layer and the upper electrode and is thin enough to allow the tunneling of electrons. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification