VARIABLE RESISTANCE MEMORY DEVICE AND METHOD OF MANUFACTURING THE SAME
A variable resistance memory device and a method of manufacturing the same are provided. The variable resistance memory device includes a multi-layered insulating layer including a plurality of holes formed on a semiconductor substrate, a lower electrode formed in a bottom of each of the holes, a first spacer formed on the lower electrode and a sidewall of each of the holes, a second spacer formed on an upper sidewall of the first spacer, a third spacer formed on a lower sidewall of the first spacer below the second spacer, a variable resistance part that is formed on the lower electrode has a height lower than a height of a top of each hole, and an upper electrode formed on the variable resistance part to be buried in each hole.
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This application claims priority under 35 U.S.C. 119(a) to Korean application number 10-2013-0081559, filed on Jul. 11, 2013, in the Korean Patent Office, which is incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION1. Technical Field
Various embodiments of the inventive concept relate to a nonvolatile memory device, and more particularly, to a variable resistance memory device and a method of manufacturing the same.
2. Related Art
In recent years, with demands on semiconductor devices with high performance and low power, next generation semiconductor memory devices with non-volatility and non-refresh have been researched, As one of the next-generation semiconductor memory devices, variable resistance memory devices are suggested. Examples of the variable resistance memory devices includes random access memory devices (PCRAMs), resistive RAMs (ReRAMs), magnetic RAMs (MRAMs), spin-transfer torque magnetoresistive RAMs (STTMRAMs), and polymer RAMs (PoRAMs) operation to have a set state or a reset state by controlling a phase-change material, which constitutes a data storage unit, to a crystalline state or an amorphous state.
Attempts to reduce a reset current, that is, a current required to switch a phase-change material to an amorphous state in PCRAMs have been made, Reduction in the reset current of the PCRAMs may be determined by a resistance of the phase-change material layer and a contact area between a lower electrode and the data storage unit.
Thus, at present, attempts to reduce the contact area between the lower electrode and the data storage unit, which may be controlled by a process, have been made increasingly.
SUMMARYIn an embodiments are provided to a variable resistance memory device capable of reducing a reset current, and a method of manufacturing the same.
According to one aspect of an exemplary embodiment, there is provided a variable resistance memory device. The variable resistance memory device may include a multi-layered insulating layer including a plurality of holes formed on a semiconductor substrate, a lower electrode formed in a bottom of each of the holes, a first spacer formed on the lower electrode and a sidewall of each of the holes, a second spacer formed on an upper sidewall of the first spacer, a third spacer formed on a lower sidewall of the first spacer below the second spacer, a variable resistance part that is formed on the lower electrode has a height lower than a height of a top of each hole, and an upper electrode formed on the variable resistance part to be buried in each hole.
According to an aspect of an exemplary embodiment, there is provided a method of manufacturing a variable resistance memory device. The method may include forming a multi-layered insulating layer on a semiconductor substrate, forming a hole exposing a portion of an upper surface of the semiconductor substrate by etching the multi-layered insulating layer, forming a lower electrode in a bottom of the hole, forming a first spacer on the lower electrode and a sidewall of the hole, forming a second spacer on an upper sidewall of the first spacer, forming a third spacer on a lower sidewall of the first spacer, forming a variable resistance part in the hole to have a height lower than that of the hole, and forming an upper electrode on the variable resistance part to be buried in the hole.
According to an aspect of an exemplary embodiment, there is provided a method of manufacturing a variable resistance memory device. The method may include forming a multi-layered insulating layer on a semiconductor substrate, forming a hole exposing a portion of an upper surface of the semiconductor substrate by etching the multi-layered insulating layer, forming a lower electrode in a bottom of the hole, forming a first spacer on the lower electrode and a sidewall of the hole, forming a second spacer protruded from an upper sidewall of the first spacer, depositing a third spacer material into the hole, forming a third spacer on a lower sidewall of the first spacer and below the second spacer by selectively etching the third spacer material, forming a variable resistance part in the hole to have a height lower than that of the hole.
These and other features, aspects, and embodiments are described below in the section entitled “DETAILED DESCRIPTION”
The above and other aspects, features and other advantages of the subject matter of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, exemplary embodiments will be described in greater detail with reference to the accompanying drawings.
Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the particular shapes of regions illustrated herein but may be to include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. It is also understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other or substrate, or intervening layers may also be present. In addition, a singular form may include a plural form as long as it is not specifically mentioned in a sentence.
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As illustrated in FIG, 7, a variable resistance material is deposited to be buried in the hole H. The variable resistance material 170 may be recessed to have a certain height, and thus a variable resistance part 170 having a height lower than that of the hole H may be formed. The variable resistance part 170 may include a phase-change material of which a resistance is changed depending on a crystalline state or an amorphous state according to a temperature, for example, Ge2Sb2Te5 (GST).
As illustrated in
As described above, in the variable resistance memory device according to an embodiment of the inventive concept, since the lower electrode 130 and the variable resistance part 170 are in contact with each other through the key hole KH, a contact area may be reduced, and thus a reset current may be reduced.
The above embodiment of the present invention is illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the embodiment described herein. Nor is the invention limited to any specific type of semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
Claims
1. A variable resistance memory device, comprising:
- a multi-layered insulating layer including a plurality of holes formed on a semiconductor substrate;
- a lower electrode formed in a bottom of each of the holes;
- a first spacer formed on the lower electrode and a sidewall of each of the holes;
- a second spacer formed on an upper sidewall of the first spacer to a predetermined height;
- a third spacer formed on a lower sidewall of the first spacer below the second spacer;
- a variable resistance part that is formed on the lower electrode has a height lower than a height of a top of each hole; and
- an upper electrode formed on the variable resistance part to be buried in each hole.
2. The variable resistance memory device of claim, wherein the multi-layered insulating layer includes:
- a first insulating layer formed on the lower electrode and formed of nitride;
- a second insulating layer formed on the first insulating layer and formed of oxide;
- a third insulating layer formed on the second insulating layer and formed of the nitride; and
- a fourth insulating layer formed on the third insulating layer and formed of the oxide.
3. The variable resistance memory device of claim 2, wherein the second spacer is formed through selectively oxidizing the first spacer.
4. The variable resistance memory device of claim 3, wherein the first spacer, the second spacer, and the third spacer are formed of materials having different etch selectivities from each other.
5. The variable resistance memory device of claim 4, wherein a height of the variable resistance part is higher than that of the third spacer.
6. A method of manufacturing a variable resistance memory, device, the method comprising:
- forming a multi-layered insulating layer on a semiconductor substrate;
- forming a hole exposing a portion of an upper surface of the semiconductor substrate by etching the multi-layered insulating layer;
- forming a lower electrode in a bottom of the hole;
- forming a first spacer on the lower electrode and a side ail of the hole;
- forming a second spacer on an upper sidewall of the first spacer;
- forming a third spacer on a lower sidewall of the first spacer;
- forming a variable resistance part in the hole to have a height lower than that of the hole; and
- forming an upper electrode on the variable resistance part to be buried in the hole.
7. The method of claim 6, wherein the multi-layered insulating layer includes:
- a first insulating layer formed on the lower electrode and formed of nitride;
- a second insulating layer formed on the first ins ting layer and formed of oxide;
- a third insulating layer formed on the second insulating layer and formed of the nitride; and
- a fourth insulating layer formed on the third insulating layer and formed of the oxide.
8. The method of claim 7, wherein the fourth insulating layer is removed using the third insulating layer as an etch stopper layer in the forming of the upper electrode.
9. The method of claim 8, wherein the second spacer is formed by oxidizing the first spacer in the forming of the second spacer.
10. The method of claim 9, further comprising a sacrificial layer having a certain height in the hole after the forming of the first spacer,
11. The method of claim 10, further comprising removing the sacrificial layer after the forming of the second spacer.
12. The method of claim 11, wherein a height of the variable resistance part is formed to be higher than that of the third spacer in the forming of the variable resistance part.
13. A method of manufacturing a variable resistance memory device, the method comprising:
- forming a multi-layered insulating layer on a semiconductor substrate;
- forming a hole exposing a portion of an upper surface of the semiconductor substrate by etching the multi-layered insulating layer;
- forming a lower electrode in a bottom of the hole;
- forming a first spacer on the lower electrode and a sidewall of the hole;
- forming a second spacer protruded from an upper sidewall of the first spacer;
- depositing a third spacer material into the hole;
- forming a third spacer on a lower sidewall of the first spacer and below the second spacer by selectively etching the third spacer material; and
- forming a variable resistance part in the hole to have a height lower than that of the hole.
14. The method of claim 13, further comprising forming an upper electrode on the variable resistance part to be buried in the hole.
15. The method of claim 14, wherein the second spacer is formed by oxidizing the first spacer in the forming of the second spacer.
16. The method of claim 15, wherein the multi -layered insulating layer includes:
- a first insulating layer formed on the lower electrode and formed of nitride;
- a second insulating layer formed on the first insulating layer and formed of oxide;
- a third insulating layer formed on the second insulating layer and formed of the nitride; and
- a fourth insulating layer formed on the third insulating layer and formed of the oxide,
17. The method of claim 16, wherein the third spacer material is nitride.
Type: Application
Filed: Oct 2, 2013
Publication Date: Jan 15, 2015
Applicant: SK hynix inc. (Gyeonggi-do)
Inventors: Ha Chang JUNG (Gyeonggi-do), Gi A LEE (Gyeonggi-do)
Application Number: 14/044,367
International Classification: H01L 45/00 (20060101);