KR101094996B1 - Fabricating of phase change random access memory and fabricating thereof - Google Patents

Abstract

PURPOSE: A phase change memory device and a manufacturing method thereof are provided to form a diffusion preventing film between a phase change material film and an upper electrode, thereby improving the electrical features between the phase change film material film and the upper electrode. CONSTITUTION: A high concentration n-type impurity area(110) is formed in a cell area of a semiconductor substrate(100). A lower electrode(130) is formed on the high concentration n-type impurity area. A hole of an interlayer insulating film(120) with the lower electrode is buried in a phase change material film(150). A diffusion preventing film(162) is formed on the phase change material film. An upper electrode(164) is formed on the frontal surface of the subtracted with the diffusion preventing film.

Description

Phase change memory device and fabrication method thereof {Fabricating Of Phase Change Random Access Memory And Fabricating Thereof}

The present invention relates to a nonvolatile memory device and a method of manufacturing the same, and more particularly, to a phase change memory device including an upper electrode and a method of manufacturing the same.

A phase-change random access memory (PCRAM) device generates a phase change of a phase change material by applying Joule heating to the phase change material through a lower electrode serving as a heater. Data is recorded / erased using the difference in electrical resistance between the crystalline state and the amorphous state of the phase change material.

The phase change memory device has a contact hole for electrically connecting the lower electrode and the upper electrode and filling a phase change material film, which is a passage for supplying current or transmitting an electrical signal into the device.

The phase change memory device forms an upper electrode on a phase change material layer embedded in the contact hole. At this time, the tellurium (Te) component, which is one of the components forming the phase change material film, is moved toward the upper electrode. As a result, a seam is formed at the position where the tellurium (Te) component is missing. . In addition, a gap exists between the phase change material film and the upper electrode, causing a problem of increasing contact resistance.

In addition, as the tellurium (Te) component of the phase change material film moves to the upper electrode, the composition ratio of the phase change material film does not maintain a normal composition ratio, which causes a problem that causes device malfunction.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and is intended to improve electrical characteristics between the phase change material film and the upper electrode.

A method of manufacturing a phase change memory device according to an embodiment of the present invention includes forming a lower electrode on an upper portion of a semiconductor substrate; Forming a phase change material film filling a hole in the interlayer insulating film on which the lower electrode is formed; Forming a diffusion barrier layer on the phase change material layer, the titanium concentration of which increases as the thickness thereof increases; And forming an upper electrode on an entire surface of the substrate on which the diffusion barrier is formed.

A phase change memory device according to another exemplary embodiment of the present disclosure may include a lower electrode formed on a semiconductor substrate; A phase change material film formed on the lower electrode; A diffusion barrier layer in which titanium concentration increases as the thickness formed on the phase change material layer increases; And an upper electrode formed on the diffusion barrier.

The manufacturing method of the phase change memory device according to the present invention is effective in improving the electrical characteristics between the phase change material film and the upper electrode by forming a diffusion barrier between the phase change material film and the upper electrode.

1 to 6 are cross-sectional views sequentially illustrating a method of manufacturing a phase change memory device according to an embodiment of the present invention; and
7 and 8 are cross-sectional views illustrating a method of manufacturing a phase change memory device according to another exemplary embodiment of the present invention.

1 to 6 are cross-sectional views sequentially illustrating a method of manufacturing a phase change memory device according to an embodiment of the present invention.

Referring to FIG. 1, a diode pattern 135 as a switching element is formed on a semiconductor substrate 100 on which a high concentration n-type impurity region 110 is formed.

In more detail, the high concentration n-type impurity region 110 is formed in the cell region of the semiconductor substrate 100. The high concentration n-type impurity region 110 may be formed by implanting n-type impurity ions having a high concentration, followed by a heat treatment process.

The high concentration n-type impurity region 110 of the cell region may be formed at the same time as a junction region (not shown) formed in the peripheral region as a word line region. The first interlayer insulating layer 120 is formed on the semiconductor substrate 100 on which the high concentration n-type impurity region 110 is formed.

The first interlayer insulating layer 120 may be a high density plasma (HDP) film having dense film quality characteristics and including interlayer planarization characteristics. The hole 122 is formed by etching the first interlayer insulating layer 120 to expose a predetermined portion of the high concentration n-type impurity region 110.

Subsequently, the diode pattern 135 including the n-type selective epitaxial growth (SEG) layer 132 and the p-type SEG layer 134 is formed in the hole 122. In this case, the diode pattern 135 is formed in the hole 122 and then performs a chemical mechanical polishing (CMP) process and / or blanket etching.

Next, referring to FIG. 2, a lower electrode material layer (not shown) is coated on the diode pattern 135 to form the lower electrode 130.

In the present embodiment, the material layer for the lower electrode is provided to cause phase change of the phase change material by applying Joule heating to the phase change material. For example, a titanium film (Ti) or a titanium nitride film (TiN) Can be. Such a titanium film (Ti) or titanium nitride film (TiN) has a natural oxidation and surface agglomeration characteristics better than other refractory metal film, and provides a large resistivity.

Referring to FIG. 3, spacers 140 are formed on sidewalls of the hole 122.

First, a spacer insulating film (not shown) is formed on the entire surface of the substrate 100 on which the lower electrode 130 is exposed, and then a spacer 140 is formed through etching and etch back processes, and the bottom of the spacer 140 has a lower electrode. It is formed so as to overlap a part of the 140. The spacer 140 in the present invention is for minimizing the size of the hole 122. For example, the spacer 140 is formed of at least one of a nitride film and an oxide film.

4, a phase change material film 150 is embedded in the contact hole 155 in a region surrounded by the lower electrode 130 and the spacer 140. The phase change material layer 150 may reduce the contact area with the lower electrode 130 by the spacer 140.

Referring to FIG. 5, a diffusion barrier layer 162 is formed in the resultant material in which a titanium (Ti) concentration increases as the thickness increases on the phase change material layer 150. Substantially, the titanium (Ti) concentration of the diffusion barrier layer 162 is relatively lower than the titanium (Ti) concentration of the upper electrode.

More specifically, the diffusion barrier material layer may be formed by depositing any one of physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD) on the entire surface of the substrate on which the phase change material layer 150 is formed. After deposition (not shown), the diffusion barrier layer 162 is formed by performing a chemical mechanical polishing (CMP) process and / or blanket etching to have a predetermined thickness.

In this case, the thickness h1 of the diffusion barrier 162 may be smaller than the thickness h2 of the upper electrode 180 (see FIG. 6) to be formed later. The reason for this is that the diffusion barrier 162 prevents the tellurium (Te) component, which is one of the components of the phase change material layer 150, from moving to the upper electrode 164, and the tellurium (Te) component. The thickness of the upper electrode 164 is preferably smaller than the thickness of the upper electrode 164 because it is sufficient to not move toward the upper electrode 164.

The diffusion barrier 162 uses any one of a titanium silicide nitride (TiSiN), a titanium aluminum nitride (TiAlN), a titanium silicide nitride (TiSiCxN), and a titanium aluminum nitride (TiAlCxN).

In addition, when the diffusion barrier 162 includes carbon, the diffusion barrier 162 may be formed through a process of adjusting the carbon concentration in the diffusion barrier 162 after deposition of the diffusion barrier material layer, wherein, For example, the concentration is preferably adjusted to 3% to 50%.

The reason for controlling the carbon concentration in the diffusion barrier material film is to leave only the source component of titanium (Ti), which is one of the components of the diffusion barrier film 162, so that the tellurium component Te of the phase change material film 150 This is to strengthen the movement.

As a process for adjusting the carbon concentration in the diffusion barrier 162, a plasma or remote that can be deposited at low temperature using a process of gradually increasing the titanium (Ti) injection time and / or the titanium (Ti) injection amount, or It is possible to use a plasma (Remote Plasama).

Here, when using a plasma or a remote plasma process, for example, a treatment gas of any one of nitrogen (N 2), argon (Ar), hydrogen (H 2) and ammonia (NH 3) may be used.

In the present invention, the diffusion barrier layer 162 increases the concentration of titanium (Ti) as the thickness increases, reducing the occurrence of by-products such as Te-Ti at the junction with the phase change material layer 150, thereby increasing the contact resistance Can be prevented.

In addition, in the present invention, in the case of forming the diffusion barrier layer 162 by controlling the concentration of carbon through a plasma or remote plasma process, a ligand that is not decomposed properly at a high temperature while removing impurities such as carbon (C). You can break down the legs.

In addition, although the diffusion barrier layer 162 according to the present invention is formed to cover the entire surface of the substrate on which the phase change material layer 150 is formed, the present invention is not limited thereto. Since it is to prevent the rulium (Te) component from moving to the upper electrode 162, it may be formed only in a portion where the phase change material film 150 is formed as shown in FIG.

Referring to FIG. 6, the upper electrode 164 is formed on the diffusion barrier layer 162 by a known technique in the above result, so that the diffusion barrier layer 162 and the upper electrode 164 have a structure 1602. Can be formed.

In this case, the upper electrode 164 is preferably formed of a titanium film Ti or a titanium nitride film TiN to be electrically connected to the phase change material film 150.

According to the present invention, the diffusion barrier layer 162 and the upper electrode 164, which can prevent leakage of the tellurium component of the phase change material layer 150, are formed as one structure, thereby forming one of the components that form the phase change material layer. It is possible to prevent the tellurium (Te) component from moving toward the upper electrode 164. Accordingly, the present invention prevents the formation of a seam by leaking tellurium (Te) components into the phase change material film 150 and at the same time a gap between the phase change material film 150 and the upper electrode 164. Increase of contact resistance by a gap can be prevented.

In addition, according to the present invention, as the tellurium (Te) component of the phase change material film 150 moves to the upper electrode 164, the composition ratio of the phase change material film does not maintain a normal composition ratio, causing malfunction of the device. Problems can be prevented.

8 illustrates a phase change memory device according to another embodiment of the present invention. 8 is a cross-sectional view illustrating a method of manufacturing an upper electrode generated after a process of generating a phase change material film in a method of manufacturing a phase change memory device according to another exemplary embodiment of the present invention.

Referring to FIG. 8, more specifically, after depositing the upper electrode 160 on the phase change material film 150 using any one of PVD, CVD, and ALD, a chemical mechanical polishing (CMP) process. And blanket etching is performed.

In this case, the upper electrode 160 may be formed of the same titanium silicide nitride layer (TiSiN), titanium aluminum nitride layer (TiAlN), titanium silicide nitride layer (TiSiCxN), and titanium aluminum nitride layer (TiAlCxN) as in the diffusion barrier layer 162 of FIG. 5. Use either one. The upper electrode 160 is formed of the same material as the diffusion barrier 162 of FIG. 5 because the upper electrode 160 uses a titanium film Ti as shown in FIG. 6, and the diffusion barrier 162 is formed. In addition, since the titanium film (Ti) series is used, it can be formed as the upper electrode 160 that can also be used as a diffusion barrier to prevent the Te component at once without an additional process method.
In addition, as the upper electrode 160 has a characteristic of the diffusion barrier 162 of FIG. 5, as the thickness of the upper electrode 160 increases, the concentration of titanium (Ti) also increases.

As such, the present invention forms an upper electrode 160 that serves to prevent diffusion of the tellurium component of the phase change material film 150, thereby forming tellurium, which is one of the components forming the phase change material film. The phenomenon in which the Te) component moves toward the upper electrode 160 can be prevented. Accordingly, the present invention prevents the formation of a seam by leaking tellurium (Te) components into the phase change material film 150 and at the same time a gap between the phase change material film 150 and the upper electrode 160. It is possible to prevent the contact resistance caused by the gap.

In addition, according to the present invention, as the tellurium (Te) component of the phase change material film 150 moves to the upper electrode 160, the composition ratio of the phase change material film does not maintain a normal composition ratio, causing malfunction of the device. Problems can be prevented.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

100: substrate 110: high concentration n-type impurity region
120: interlayer insulating film 135: diode pattern
130: lower electrode 140: spacer
150: phase change material film 162: diffusion barrier film
164: upper electrode

Claims (11)

Forming a lower electrode on the semiconductor substrate;
Forming a phase change material film filling a hole in the interlayer insulating film on which the lower electrode is formed;
Forming a diffusion barrier layer on the phase change material layer, the titanium concentration of which increases as the thickness thereof increases; And
And forming an upper electrode on an entire surface of the substrate on which the diffusion barrier is formed. Claim 2 has been abandoned due to the setting registration fee. The method according to claim 1,
And the thickness of the diffusion barrier layer is smaller than the thickness of the upper electrode. Claim 3 was abandoned when the setup registration fee was paid. The method of claim 2,
The diffusion barrier layer is one of a titanium silicide nitride (TiSiN), titanium aluminum nitride (TiAlN), titanium silicide nitride (TiSiCxN) and titanium aluminum nitride (TiAlCxN) is a manufacturing method of a phase change memory device. delete Claim 5 was abandoned upon payment of a set-up fee. The method of claim 3,
If the diffusion barrier comprises carbon, the carbon concentration is adjusted to 3% to 50% of the manufacturing method of the phase change memory device. Claim 6 was abandoned when the registration fee was paid. The method of claim 5,
The diffusion barrier layer is a method of manufacturing a phase change memory device to be formed while gradually increasing the titanium injection time. Claim 7 was abandoned upon payment of a set-up fee. The method of claim 5,
The diffusion barrier layer is a method of manufacturing a phase change memory device which is formed while gradually increasing the titanium injection amount. Claim 8 was abandoned when the registration fee was paid. The method of claim 5,
The diffusion barrier layer is a carbon film (Carbon) formed by using a plasma or a remote plasma manufacturing method of a phase change memory device. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 8,
The plasma or remote plasma processing gas is any one of nitrogen (N 2), argon (Ar), hydrogen (H 2) and ammonia (NH 3). A lower electrode formed on the semiconductor substrate;
A phase change material film formed on the lower electrode;
A diffusion barrier layer in which titanium concentration increases as the thickness formed on the phase change material layer increases; And
Phase change memory device comprising an upper electrode formed on the diffusion barrier. Claim 11 was abandoned upon payment of a setup registration fee. The method of claim 10,
And the thickness of the diffusion barrier layer is smaller than the thickness of the upper electrode.

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