KR20090021067A - Method of increasing energy band gap of crystalline aluminum oxide layer and method of manufacturing charge trap memory device comprising crystalline aluminum oxide layer having high energy band gap - Google Patents

Abstract

A method of increasing energy band gap of a crystalline aluminum oxide layer and a method of manufacturing a charge trap memory device comprising a crystalline aluminum oxide layer having high energy band gap are provided to increase an energy band gap of a crystalline aluminum oxide layer by forming a crystalline aluminum oxide layer with a wet oxidation process and a thermal process. An amorphous aluminum oxide layer(20b) is formed on an underlayer(18) in order to enhance energy band gap of an aluminum oxide layer. Hydrogen(H) or hydroxyl radical(OH) is introduced within the amorphous aluminum oxide layer. The amorphous aluminum oxide layer is crystallized. The hydrogen or the hydroxyl radical is injected with one method among wet-oxidization, ion implantation and plasma doping. The aluminum oxide layer is heat-treated in 800~1300°C.

Description

Method of increasing energy band gap of crystalline aluminum oxide layer and method of manufacturing charge trap memory A method of manufacturing a charge trap memory device comprising a crystalline aluminum oxide layer having a high energy band gap and a method of manufacturing charge trap memory device comprising crystalline aluminum oxide layer having high energy band gap}

The present invention relates to a method of manufacturing a memory device, and more particularly, to a method of increasing the energy band gap of an amorphous aluminum oxide layer and a method of manufacturing a charge trap memory device including a crystalline aluminum oxide layer having a high energy band gap. .

The charge retention capability of a charge trap flash memory device (hereinafter, referred to as a memory device) consisting of a metal electrode, a blocking oxide film, a charge trap layer, a tunneling oxide film, and a silicon substrate is characterized by the deep trap energy of the charge trap layer, the thickness of the tunneling oxide film, and the like. It is determined by electrical characteristics such as dielectric constant and energy band gap of the blocking oxide film.

The energy band gap of the blocking oxide is directly related to the charge retention capability of the memory device. When the energy band gap of the blocking oxide film is large, it is difficult for the charge stored in the charge trap layer of the memory device to escape to the metal electrode through the blocking oxide film. In other words, the larger the energy band gap of the blocking oxide film, the more leakage of charge from the charge trap layer through the blocking oxide film can be suppressed.

Currently, an aluminum oxide film having an energy band gap of 6.5 eV and a thermodynamically stable aluminum oxide film is widely used as a blocking oxide film of the memory device.

However, the charge retention capability of the aluminum oxide layer may not be sufficient for the next generation memory device. In other words, since the integration degree of the next-generation memory device will be much higher than that of the present, the thickness of the blocking oxide film will also be thin, and thus, it may be difficult to use the aluminum oxide film which is widely used as the blocking oxide film of the next-generation memory device.

Therefore, a blocking oxide film having a larger energy band gap is required to secure stable charge retention capability of the next-generation memory device.

The technical problem to be achieved by the present invention is to improve the above-described problems of the prior art, a method of increasing the energy band gap of the crystalline aluminum oxide layer, which can increase the charge blocking ability of the crystalline aluminum oxide layer used as the charge blocking layer. In providing.

Another object of the present invention is to provide a method for manufacturing a charge trap memory device capable of increasing a stable charge holding capability.

Another object of the present invention is to provide a method for manufacturing a charge trap memory device that can simplify the manufacturing process.

In order to achieve the above technical problem, the present invention provides a first step of forming an amorphous aluminum oxide layer on a lower layer, a second step of introducing hydrogen (H) or a hydroxyl group (OH) in the amorphous aluminum oxide layer and the hydrogen Or a third step of crystallizing the amorphous aluminum oxide layer into which the hydroxyl group is introduced.

In the second step, the hydrogen or hydroxyl group may be introduced by any one of wet oxidation, ion implantation, and plasma doping.

According to another embodiment of the present invention, the first and second steps may be performed in one process. For example, the aluminum oxide layer may be formed by depositing an aluminum oxide layer by vapor deposition or atomic layer deposition (ALD). It can be introduced into the layer. In this case, the aluminum oxide layer may be deposited as amorphous or crystalline including hydrogen or hydroxyl groups. When the aluminum oxide layer is deposited with crystalline hydrogen or hydroxyl, the third step may be a process of removing hydrogen or hydroxyl from the crystalline aluminum oxide layer including hydrogen or hydroxyl.

According to another embodiment of the present invention, when introducing hydrogen or a hydroxyl group into the amorphous aluminum oxide layer in the second step, the amorphous aluminum oxide layer with a process temperature of 800 ℃ or more, preferably 800 ~ 850 ℃ Can be changed to a crystalline aluminum oxide layer comprising hydrogen or hydroxyl groups. In this case, the third step may be a heat treatment process for removing hydrogen or hydroxyl groups from the crystalline aluminum oxide layer including the hydrogen or hydroxyl groups.

According to an embodiment of the present invention, after performing the first and second steps, the aluminum oxide layer may be heat treated at 800 to 1300 ° C. in the third step. At this time, the heat treatment of the amorphous aluminum oxide layer at a temperature lower than the crystallization temperature of the amorphous aluminum oxide layer may be further included before the heat treatment.

The wet oxidation can be carried out at atmospheric high temperature conditions, low pressure high temperature conditions or high pressure low temperature conditions.

According to another embodiment of the present invention, the densification process may be performed on the amorphous aluminum oxide layer formed in the first step, but the densification process may be performed before or after the wet oxidation, but before the wet oxidation. More preferably, prior to injection of hydrogen or hydroxyl groups.

In order to achieve the above another technical problem, the present invention provides a method for manufacturing a charge trap memory device including a tunneling film, a charge trap layer, a charge blocking layer and a gate electrode, wherein the forming of the charge blocking layer is the charge trap A first step of forming an amorphous aluminum oxide layer on the layer, a second step of introducing hydrogen (H) or a hydroxyl group (OH) into the amorphous aluminum oxide layer and crystallizing the amorphous aluminum oxide layer into which the hydrogen or hydroxyl group is introduced It provides a method of manufacturing a charge trap memory device comprising a third step.

In this manufacturing method, the crystallized aluminum oxide layer is a crystalline phase having an energy band gap of 7.0 eV or more.

According to an embodiment of the present invention, in the second step, the hydrogen (H) or the hydroxyl group may be introduced by any one of wet oxidation, ion implantation, and plasma doping.

According to another embodiment of the present invention, the first and second steps may be performed in one process as described above.

When introducing hydrogen or a hydroxyl group into the amorphous aluminum oxide layer in the second step, the amorphous aluminum oxide layer is a crystalline aluminum containing hydrogen or hydroxyl with a process temperature of 800 ℃ or more, preferably 800 ~ 850 ℃ The oxide layer can be changed. In this case, the third step may be a heat treatment process for removing hydrogen or hydroxyl groups from the crystalline aluminum oxide layer.

The third step may be a heat treatment of the aluminum oxide layer at 800 ~ 1300 ℃.

After forming the amorphous aluminum oxide layer in an oxygen-rich state in the first step, the hydrogen may be injected in the second step.

According to another embodiment of the present invention, the densification process may be performed as described above.

The tunneling film may be a silicon oxide film, silicon oxy nitride, or silicon nitride film.

The trap layer may include a plurality of nano dots or a metal doped high-k oxide, for example, may include a plurality of aluminum oxide dots.

In order to achieve the above another technical problem, the present invention provides a method for manufacturing a charge trap type memory device having a gate stack including a tunneling film, a charge trap layer, a crystalline aluminum oxide layer on the alpha and a gate electrode on a substrate. Forming an amorphous aluminum oxide layer on the charge trap layer, forming a metal layer having a crystal lattice similar to the crystal lattice of the crystalline aluminum oxide layer of the alpha phase on the amorphous aluminum oxide layer, and the metal layer being formed And heat treating the resultant to change the amorphous aluminum oxide layer into a crystalline aluminum oxide layer on the alpha phase.

In the manufacturing method, the step of converting the amorphous aluminum oxide layer into the crystalline aluminum oxide layer on the alpha includes forming a mask on the metal layer to define a region where the gate stack is to be formed, the metal layer around the mask, The method may further include sequentially etching the amorphous aluminum oxide layer, the charge trap layer, and the tunneling layer, and heat treating a resultant product on which the metal layer is formed.

After forming the amorphous aluminum oxide layer into the crystalline aluminum oxide layer of the alpha phase, forming a mask on the metal layer defining a region in which the gate stack is to be formed, the metal layer around the mask, the alpha phase The step of sequentially etching the crystalline aluminum oxide layer, the charge trap layer and the tunneling film and removing the mask may be further performed.

The heat treatment of the resultant metal layer may be performed after removing the mask.

The metal layer may be formed of any one of a TiCN layer, a Ru layer having a crystal direction of (0001), and a Rh 2 O 3 layer.

When the metal layer is an Rh2O3 layer, heat treatment may be performed to change the metal layer to conductivity.

The heat treatment may be carried out at 1000 ~ 1300 ℃ at normal pressure.

The crystalline aluminum oxide layer used as the charge blocking layer in the manufacturing method according to the present invention is formed by a wet oxidation process and a heat treatment process. In this process, the crystal structure of the aluminum oxide layer is changed to the kappa (κ) phase or the alpha (α) phase from the gamma phase.

Therefore, using the production method of the present invention, the energy band gap of the crystalline aluminum oxide layer can be made larger than 7.0 eV. Accordingly, the charge trapped in the charge trap layer can be prevented from passing through the crystalline aluminum oxide layer to the gate electrode, thereby increasing the charge retention capability of the memory device.

In addition, in the manufacturing method according to another embodiment of the present invention, since the etching process for removing the separate material layer after forming the crystalline aluminum oxide layer of the alpha phase is unnecessary, the manufacturing process can be simplified.

Hereinafter, a method of increasing the energy band gap of a crystalline aluminum oxide layer and a method of manufacturing a charge trap memory device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

First, the manufacturing method (hereinafter, the manufacturing method of the present invention) of the charge trap memory device according to the embodiment of the present invention will be described. The method of increasing the energy band gap according to an embodiment of the present invention will be described together in the manufacturing method of the present invention.

Referring to FIG. 1, the tunneling film 16, the charge trap layer 18, and the amorphous aluminum oxide layer 20a are sequentially stacked on the substrate 10. The substrate 10 is a semiconductor substrate, and may be formed of, for example, a silicon substrate, particularly a p-type silicon substrate. The tunneling film 16 may be formed of an oxide film having a predetermined thickness. For example, the tunneling film 16 may be formed of a silicon oxide film or a silicon oxy nitride film. And the charge trap layer 18 may be a material layer having trap sites of a predetermined thickness and a predetermined density, for example, may be a silicon nitride layer, may include a plurality of nanodots, metal-doped high- It may be k oxide, for example, may include a plurality of aluminum oxide dots.

Next, the amorphous aluminum oxide layer 20a is formed of an amorphous aluminum oxide layer 20b (hereinafter, referred to as OH-material layer) in which an OH bond exists, which includes hydrogen (H) or hydroxyl group (OH) as shown in FIG. 2. To).

The OH-material layer 20b may be formed by introducing hydrogen or a hydroxyl group into the amorphous aluminum oxide layer 20a by a wet oxidation method. The wet oxidation method can be carried out at a predetermined temperature and pressure in a steam atmosphere. The wet oxidation may be carried out by heat treatment at high temperature at atmospheric pressure or by heat treatment at high pressure at low temperature. In addition, the temperature of the wet oxidation may vary depending on the charge trap layer 18. For example, when the charge trap layer 18 is a silicon nitride (SiN) film, the wet oxidation may be performed at 500 ° C to 1000 ° C.

By the wet oxidation, H bonds or OH bonds increase in the amorphous aluminum oxide layer 20a.

Instead of the wet oxidation method, any one of ion implantation, plasma doping and furnace heat treatment may be used to inject hydrogen or hydroxyl groups. When the OH-material layer 20b is formed by the ion implantation or the plasma doping method, the amorphous aluminum oxide layer 20b implanted with hydrogen may be heat treated in an oxygen atmosphere. However, when the amorphous aluminum oxide layer 20b is an oxygen-rich, oxygen-rich amorphous aluminum oxide layer, the oxygen atmosphere heat treatment may be omitted.

The H or OH bond present in the amorphous aluminum oxide layer 20a contributes to crystal nucleation in the amorphous aluminum oxide layer 20a and serves to lower formation energy. Accordingly, when hydrogen or a hydroxyl group is injected into the amorphous aluminum oxide layer 20a by any one of the wet oxidation method, ion implantation, plasma doping, and furnace heat treatment method, the crystal structure of the amorphous aluminum oxide layer 20a is gamma phase. (γ-phase) is suppressed and can become a phase different from the gamma phase, kappa phase or alpha phase. Therefore, the energy band gap of the crystalline aluminum oxide layer obtained by the heat treatment process for crystallization described later is larger than 7.0 eV.

Meanwhile, the process of forming the amorphous aluminum oxide layer 20a and the process of wet oxidizing the amorphous aluminum oxide layer 20a may be performed in one process. For example, hydrogen or a hydroxyl group can be introduced into the aluminum oxide layer while the aluminum oxide layer is deposited by vapor deposition or atomic layer deposition (ALD). In this case, the aluminum oxide layer may be deposited as an amorphous aluminum oxide layer 20a or a crystalline aluminum oxide layer including hydrogen or a hydroxyl group. When the aluminum oxide layer is deposited with a crystalline aluminum oxide layer containing hydrogen or a hydroxyl group, the heat treatment process for crystallization of the amorphous aluminum oxide layer 20a to be described below is performed in a hydrogen-crystalline crystalline aluminum oxide layer including hydrogen or a hydroxyl group. Or it may be a process of removing the hydroxyl group.

In addition, when introducing hydrogen or a hydroxyl group into the amorphous aluminum oxide layer 20a, the process temperature is 800 ° C or higher, preferably 800 to 850 ° C, and the amorphous aluminum oxide layer 20a is crystalline aluminum containing hydrogen or a hydroxyl group. The oxide layer can be changed. In this case, the heat treatment process for crystallization of the amorphous aluminum oxide layer 20a to be described below may be a process of removing hydrogen or hydroxyl groups from the crystalline aluminum oxide layer including the hydrogen or hydroxyl group.

In addition, the densification process may be performed on the amorphous aluminum oxide layer 20a, but the densification may be performed before or after the wet oxidation, but before the wet oxidation, immediately before the hydrogen or the hydroxyl group is injected. It may be more desirable.

Subsequently, as shown in FIG. 3, the resultant in which the OH-material layer 20b is formed is heat-treated. In this case, the heat treatment may be performed once or divided into two times.

When the heat treatment is performed once, the heat treatment may be performed at a predetermined temperature, for example, 800 ° C to 1300 ° C. Through this one high temperature heat treatment, the hydrogen or hydroxyl groups contained in the OH-material layer 20b are removed while the OH-material layer 20b becomes the crystalline aluminum oxide layer 20 as shown in FIG. 4. The crystalline aluminum oxide layer 20 is a charge blocking layer. Despite the process of removing hydrogen or hydroxyl groups, hydrogen or hydroxyl groups may be present in the crystalline aluminum oxide layer 20 to some extent.

On the other hand, when the heat treatment is divided into two times, the first heat treatment may be a heat treatment for removing hydrogen or hydroxyl groups from the OH-material layer (20b). The first heat treatment is performed at a temperature lower than the crystallization temperature of the OH-material layer 20b. The secondary heat treatment may be performed in the same manner as when the heat treatment is performed once.

5, the gate electrode 22 is formed on the crystalline aluminum oxide layer 20. The gate electrode 22 may be a conductive layer having a work function of 4 eV or more, for example, a tantalum nitride (TaN) layer. A mask M1 defining a gate formation region is formed on the gate electrode 22. Anisotropic etching is performed around the mask M1 until the substrate 10 is exposed. As a result, as shown in FIG. 6, a gate stack including a tunneling film 16, a charge trap layer 18, a crystalline aluminum oxide layer 20, and a gate electrode 22, which are sequentially stacked, is formed. After the anisotropic etching, the mask M1 is removed.

Referring to FIG. 7, after the mask M1 is removed, conductive impurities are implanted into the substrate 10 using the remaining gate stack as a mask. In this case, the conductive impurity is a type opposite to the impurity injected into the substrate 10 and may be, for example, an n-type impurity. As a result of ion implantation of the conductive impurities, first and second shallow impurity regions 12a and 14a are formed in the substrate 10.

Referring to FIG. 8, gate spacers 24 are formed on side surfaces of a stack of tunneling films 16, charge trap layers 18, crystalline aluminum oxide layers 20, and gate electrodes 22 sequentially stacked. . The gate spacer 24 may be formed of a silicon oxide film. The conductive impurity 26 is ion implanted into the substrate 10 using the laminate and the gate spacer 24 as a mask. The conductive impurity 26 may be of a type opposite to that of the impurity implanted into the substrate 10. The ion implantation energy of the conductive impurity 26 may be greater than the ion implantation energy of the conductive impurity implanted to form the first and second shallow impurity regions 12a and 14a. Therefore, the conductive impurity 26 reaches a region deeper than the first and second shallow impurity regions 12a and 14a. As a result, regions outside the gate spacer 24 in the first and second shallow impurity regions 12a and 14a are deeper than regions below the gate spacer 24. In this manner, as shown in FIG. 9, the first and second impurity regions 12 and 14 in the LDD form are formed on the substrate 10, and the charge trap memory device has a charge blocking layer having an energy band gap of greater than 7.0 eV. Is formed. Subsequent processes may proceed according to conventional procedures.

Meanwhile, in FIG. 1, instead of the amorphous material layer 20a, a crystalline material layer, for example, a crystalline aluminum oxide layer may be formed. In this case, the heat treatment of FIG. 3 may be a recrystallization process for the aluminum oxide layer.

The following describes an experimental example conducted to verify whether the energy band gap of the crystalline aluminum oxide layer (Al 2 O 3) obtained through the wet oxidation method and subsequent heat treatment in the above-described manufacturing method is increased.

FIG. 10 shows the results of X-ray diffraction analysis on the Al 2 O 3 layer obtained by performing the wet oxidation at a high pressure and a low temperature in the above experiment, and then performing one or two heat treatments as described above.

FIG. 11 shows the results of the REELS analysis, which shows the energy band gap of the Al 2 O 3 layer having the X-ray diffraction analysis result of FIG. 10. In the case of the Al2O3 specimen for REELS analysis of FIG. 11, the densification process was performed at 800 ° C. before wet oxidation.

In FIG. 10, the first graph G1 shows an X-ray diffraction analysis of the crystalline aluminum oxide layer obtained by crystallizing the amorphous aluminum oxide layer at 1100 ° C .--> wet oxidation-> removing hydroxyl group and recrystallization at 1000 ° C. Indicates. The second graph (G2) shows the X-rays of the crystalline aluminum oxide layer obtained through crystallization of the amorphous aluminum oxide layer at 1100 ° C .--> wet oxidation-> removing hydroxyl groups at 600 ° C-> recrystallization at 1000 ° C. The results of diffraction analysis are shown. The third graph (G3) shows the results for the crystalline aluminum oxide layer obtained through densification of the amorphous aluminum oxide layer at 800 ° C .--> wet oxidation-> removal of the hydroxyl groups and crystallization at 1000 ° C. The fourth graph (G4) shows the results for the crystalline aluminum oxide layer obtained through densification of the amorphous aluminum oxide layer at 800 ° C-> wet oxidation-> removing hydroxyl groups at 600 ° C-> crystallization at 1000 ° C. . The fifth graph (G5) shows the results for the crystalline aluminum oxide layer obtained through the wet oxidation of the amorphous aluminum oxide layer-> 1000 ° C. through the hydroxyl group removal and crystallization process. The sixth graph (G6) shows the results for the crystalline aluminum oxide layer obtained through the wet oxidation of the amorphous aluminum oxide layer-> hydroxyl removal at> 600 ° C-> crystallization at 1000 ° C.

Comparing the first to sixth graphs G1 -G6, it can be seen that the peak P1 indicated when the crystal structure is gamma phase disappears from the first graph G1 to the sixth graph G6.

From these results, it can be seen that the gamma phase was suppressed in the finally obtained crystalline aluminum oxide layer when the amorphous aluminum oxide layer was changed to the crystalline aluminum oxide layer according to the production method of the present invention. This means that when applying the manufacturing method of the present invention, in the process of changing the amorphous aluminum oxide layer to crystalline, the crystal structure can be changed into a kappa phase or an alpha phase having a larger energy band gap than the gamma phase.

Referring to FIG. 11, it can be seen that the energy band gap of the Al 2 O 3 layer used to obtain the X-ray diffraction analysis result of FIG. 10 is 6.87 eV, which is higher than 6.5 eV of Al 2 O 3 on gamma. However, the densification process halved the effect of increasing the energy band gap.

FIG. 12 shows the results of X-ray diffraction analysis of the Al 2 O 3 layer obtained by performing the wet oxidation at atmospheric pressure and high temperature in the above experiment, and then performing one or two heat treatments as described above.

FIG. 13 shows a result of REELS analysis which shows an energy band gap of an Al 2 O 3 layer having the X-ray diffraction analysis result of FIG. 12.

In FIG. 12, the first graph G11 illustrates X-ray rotation analysis results of the crystalline aluminum oxide layer obtained by wet oxidation of the amorphous aluminum oxide layer at 1000 ° C .--> hydroxyl removal and recrystallization at 1000 ° C. FIG. The second graph (G22) shows the results for the crystalline aluminum oxide layer obtained through wet oxidation of the amorphous aluminum oxide layer at 1000 ° C .--> hydroxyl removal at 600 ° C-> recrystallization at 1000 ° C. The third graph G33 shows the results for the crystalline aluminum oxide layer obtained through crystallization of the amorphous aluminum oxide layer at 1100 ° C .-- wet oxidation at> 700 ° C .--> removing of hydroxyl groups and recrystallization at 1000 ° C. The fourth graph (G44) is for the crystalline aluminum oxide layer obtained through crystallization of the amorphous aluminum oxide layer at 1100 ° C-> wet oxidation at 700 ° C-> removing hydroxyl groups at 600 ° C-> recrystallization at 1000 ° C. Results are shown. The fifth graph (G55) shows the results for the crystalline aluminum oxide layer obtained through wet oxidation of the amorphous aluminum oxide layer at 700 ° C .-> 1000 ° C. through a hydroxyl group removal and crystallization process. The sixth graph (G66) shows the results for the crystalline aluminum oxide layer obtained through the wet oxidation of the amorphous aluminum oxide layer at 700 ° C-> removal of hydroxyl groups at> 600 ° C-> crystallization at 1000 ° C.

Comparing the first to sixth graphs G11-G66, it can be seen that the peak P2 that appears when the crystal structure is gamma phase disappears from the first graph G11 to the sixth graph G66.

From this result, it can be seen that the gamma phase is suppressed in the finally obtained aluminum oxide layer as in FIG. 10.

Referring to FIG. 13, it can be seen that the energy band gap of the finally obtained aluminum oxide layer is increased to 7.42 eV. The energy band gap of about 7.42 eV is the energy band gap observed in the Kappa-phase Al2O3. This energy band gap can be further increased through process improvements such as the temperature of the wet oxidation process, the temperature of the hydrogen or hydroxyl removal process, the crystallization temperature or the optimization.

This conclusion suggests that the method of the present invention can not only change the crystal phase of Al 2 O 3, but also can sufficiently change the Al 2 O 3 crystal phase to an alpha phase through the improvement of the above processes.

Therefore, in the manufacturing method of the present invention, the crystalline aluminum oxide layer 20 may be formed to have a crystalline structure of an alpha phase having an energy band gap of 8 eV or more.

FIG. 14 shows the results of X-ray diffraction analysis of the crystalline Al 2 O 3 layer obtained by performing only the heat treatment at 1100 ° C., omitting the wet oxidation of the amorphous Al 2 O 3 layer in the above experiment. And FIG. 15 shows the results of the REELS analysis to know the energy band gap for the Al2O3 layer having the X-ray diffraction analysis results of FIG.

Referring to FIG. 14, it can be seen that the crystalline Al 2 O 3 layer obtained by performing only the heat treatment at 1100 ° C. without the wet oxidation has a gamma phase. 15, it can be seen that the energy band gap is about 6.56 eV.

Comparing the results of FIGS. 10 to 13 with the results of FIGS. 14 and 15, when the crystalline Al 2 O 3 layer, which is the charge blocking layer, is formed by the above-described manufacturing method, the energy band gap of the formed crystalline Al 2 O 3 layer has a crystal structure. It can be seen that is increased than the crystalline Al 2 O 3 layer which is a gamma phase.

Next, a method of manufacturing a charge trap memory device according to another embodiment of the present invention (hereinafter, another manufacturing method of the present invention) will be described with reference to FIGS. 16 to 19. In this process, the description of the members described in the above-described manufacturing method of the present invention will be omitted.

Referring to FIG. 16, the tunneling film 16, the charge trap layer 18, and the amorphous aluminum oxide layer 20a are sequentially stacked on the substrate 10. The metal layer 40 is formed on the amorphous aluminum oxide layer 20a which is a charge blocking layer. The crystal lattice of the metal layer 40 may be similar to the crystal lattice of the alpha alumina, that is, the crystalline Al 2 O 3 layer. The metal layer 40 may include, for example, a TiCN layer, a Ru layer having a crystal direction of (0001), and an Rh 2 O 3 layer.

After the metal layer 40 is formed, the resultant on which the metal layer 40 is formed is heat-treated. The heat treatment may be carried out at a given temperature at atmospheric pressure, for example at 1000-1300 ° C. Such heat treatment can be performed using, for example, a Rapid Thermal Anneal (RTA) method.

By the heat treatment, the amorphous aluminum oxide layer 20a becomes the crystalline aluminum oxide layer 20C as shown in FIG. During the heat treatment, the amorphous aluminum oxide layer 20a is crystallized to have a crystal lattice similar to the metal layer 40 under the influence of the crystal state of the metal layer 40. Since the crystal lattice of the metal layer 40 is similar to that of alpha alumina, the crystal phase of the crystalline aluminum oxide layer 20C of FIG. 17 formed as a result of the heat treatment becomes an alpha phase.

Referring to FIG. 18, a mask M2 defining a gate region is formed on the crystalline aluminum oxide layer 20C. Subsequently, the metal layer 40, the crystalline aluminum oxide layer 20C, the charge trap layer 18, and the tunneling film 16 around the mask M2 are sequentially etched. This etching is performed until the substrate 10 is exposed. 19 shows the result after the etching. After the etching, the mask M2 is removed. The gate stack 50 is formed on the substrate 10 by the etching.

Thereafter, as shown in FIG. 20, first and second shallow impurity regions 12a and 14a are formed in the substrate 10. Next, as shown in FIG. 21, the gate spacers 24 covering the side surfaces of the gate stack 50 are formed, and then the conductive impurities 26 are implanted into the first and second shallow impurity regions 12a and 14a. Thus, the first and second impurity regions 12 and 14 are formed. One of the first and second impurity regions 12 and 14 may be a source region and the other may be a drain region.

Through this process, a charge trapping memory device as shown in FIG. 22 is formed.

The process of FIGS. 20 to 22 may be the same as the process of FIGS. 7 to 9 described above.

As described above, another manufacturing method of the present invention requires a separate process of forming the crystalline aluminum oxide layer 20C on the alpha phase and then removing the material layer used to form the crystalline aluminum oxide layer 20C on the alpha phase. not. Therefore, when using the above-described other manufacturing method of the present invention, the manufacturing process can be simplified.

Meanwhile, in another manufacturing method of the present invention, when the metal layer 40 is the Rh 2 O 3 layer, the phase of the metal layer 40 may change from conductive to insulating and from insulating to conductive during the heat treatment. Since the metal layer 40 is used as the gate electrode, the phase of the metal layer 40 in the final result should be conductive.

Therefore, when the metal layer 40 is a Rh2O3 layer, after the heat treatment (hereinafter referred to as primary heat treatment) described in FIG. 16, when the phase of the metal layer 40 is insulative, the metal layer 40 is used to change the phase of the metal layer 40 to conductive. Can be secondary heat treated. The secondary heat treatment may be carried out at a temperature of 1000-1300 ℃ at normal pressure. The secondary heat treatment may be performed by, for example, an RTA method, but another method may be used.

In addition, the primary heat treatment may be performed after the etching using the mask M2 is completed. Immediately after the resultant of FIG. 19 is obtained, it may be implemented. In this case, the first heat treatment may be performed in a state in which the mask M2 is present, or may be performed after removing the mask M2.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, those skilled in the art may use other materials than the materials exemplified above as the metal layer 40. In addition, while maintaining the core technical idea of the present invention, other components of the memory device may be modified or other members may be added. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

1 through 9 are cross-sectional views illustrating a method of manufacturing a charge trap memory device according to an exemplary embodiment of the present invention.

10 is a graph showing the results of X-ray diffraction analysis on the Al 2 O 3 layer obtained by performing wet oxidation at high pressure and low temperature in the experimental example of the present invention, and then heat treating the resultant once or twice.

FIG. 11 is a photograph showing an REELS analysis result of knowing an energy band gap of an Al 2 O 3 layer having the X-ray diffraction analysis result of FIG. 10.

12 is a graph showing the results of X-ray diffraction analysis on the Al 2 O 3 layer obtained by performing wet oxidation at atmospheric pressure and high temperature in the experimental example of the present invention, and then heat treating the resultant once or twice.

FIG. 13 is a photograph showing an REELS analysis result of knowing an energy band gap of an Al 2 O 3 layer having the X-ray diffraction analysis result of FIG. 12.

FIG. 14 is a graph showing X-ray diffraction analysis results of a crystalline Al 2 O 3 layer obtained by performing only a heat treatment at 1100 ° C., omitting wet oxidation of an amorphous Al 2 O 3 layer in an experimental example of the present invention.

FIG. 15 is a photograph illustrating an REELS analysis result of knowing an energy band gap of an Al 2 O 3 layer having the X-ray diffraction analysis result of FIG. 14.

16 to 22 are cross-sectional views sequentially illustrating a method of manufacturing a charge trap memory device according to another embodiment of the present invention.

* Description of Signs of Major Parts of Drawings *

10: substrate 12, 14: first and second impurity regions

12a, 14a: first and second shallow impurity regions

16: Tunneling film 18: Charge trap layer

20: crystalline aluminum oxide layer 20a: amorphous material layer

20b: OH-material layer 22: gate electrode

24: gate spacer 26: conductive impurity

40: metal layer 20C: alpha crystalline aluminum oxide layer

50, GS: gate stack M1, M2: mask

Claims (26)

Forming a amorphous aluminum oxide layer on the lower layer; Introducing a hydrogen (H) or a hydroxyl group (OH) into the amorphous aluminum oxide layer; And And a third step of crystallizing the amorphous aluminum oxide layer into which the hydrogen or hydroxyl group is introduced. The method of claim 1, wherein the hydrogen or the hydroxyl group is injected in any one of wet oxidation, ion implantation, and plasma doping. The method of claim 1, wherein the third step, The method of increasing the energy band gap of the aluminum oxide layer, characterized in that the aluminum oxide layer is heat-treated at 800 ~ 1300 ℃. 4. The method of claim 3, further comprising heat-treating the amorphous aluminum oxide layer at a temperature lower than the crystallization temperature of the amorphous aluminum oxide layer before the heat treatment. The method of claim 2, wherein the wet oxidation is performed at atmospheric pressure, high temperature, or at high pressure and low temperature. 2. The method of claim 1 wherein the first and second steps are performed in a single process. The method of claim 1, wherein the amorphous aluminum oxide layer is crystallized while introducing the hydrogen (H) or the hydroxyl group (OH) in the second step. 7. The aluminum oxide layer of claim 6, wherein the single process introduces hydrogen or hydroxyl groups into the aluminum oxide layer while depositing the aluminum oxide layer in an amorphous or crystalline state by vapor deposition or atomic layer deposition (ALD). To increase the energy band gap. In the method of manufacturing a charge trap memory device comprising a tunneling film, a charge trap layer, a charge blocking layer and a gate electrode, Forming the charge blocking layer, Forming a layer of amorphous aluminum oxide on the charge trap layer; Introducing a hydrogen (H) or a hydroxyl group (OH) into the amorphous aluminum oxide layer; And And a third step of crystallizing the amorphous aluminum oxide layer implanted with the hydrogen or hydroxyl group. 10. The method of claim 9, wherein the crystallized aluminum oxide layer is a crystal phase having an energy band gap of 7.0 eV or more. 10. The method of claim 9, wherein in the second step, the hydrogen (H) or hydroxyl group is introduced by any one of a wet oxidation method, an ion implantation method, and a plasma doping method. The method of claim 9, wherein the third step, And a heat treatment of the aluminum oxide layer at 800 to 1300 ° C. 13. The method of claim 12, further comprising heat treating the amorphous aluminum oxide layer at a temperature lower than the crystallization temperature of the amorphous aluminum oxide layer before the heat treatment. 12. The method of claim 11, wherein the wet oxidation is performed at atmospheric pressure, high temperature, or under high pressure and low temperature. 10. The method of claim 9, wherein after introducing the hydrogen or hydroxyl group, the amorphous aluminum oxide layer containing the hydrogen or the hydroxyl group is densified before the third step. The method of claim 9, wherein the second step, When the hydrogen is introduced, further comprising the step of heat-treating the amorphous aluminum oxide layer in an oxygen atmosphere. 10. The method of claim 9, wherein the amorphous aluminum oxide layer is formed in an oxygen-rich state in the first step, and then hydrogen is injected in the second step. 18. The method of claim 17, wherein the hydrogen-implanted amorphous aluminum oxide layer is densified. 10. The method of claim 9, wherein the charge trap layer is a silicon nitride layer. A method of manufacturing a charge trapping memory device, comprising: a gate stack comprising a tunneling film, a charge trap layer, a crystalline aluminum oxide layer on an alpha layer, and a gate electrode on a substrate; Forming an amorphous aluminum oxide layer on the charge trap layer; Forming a metal layer on the amorphous aluminum oxide layer, the metal layer having a crystal lattice similar to that of the crystalline aluminum oxide layer of the alpha phase; And And heat-treating the resultant material on which the metal layer is formed to change the amorphous aluminum oxide layer into the crystalline aluminum oxide layer of the alpha phase. The method of claim 20, wherein changing the amorphous aluminum oxide layer to a crystalline aluminum oxide layer of the alpha phase, Forming a mask on the metal layer, the mask defining a region in which the gate stack is to be formed; And Sequentially etching the metal layer, the amorphous aluminum oxide layer, the charge trap layer, and the tunneling layer around the mask; And And heat-treating the resultant material on which the metal layer is formed. 21. The method of claim 20, wherein after changing the amorphous aluminum oxide layer to a crystalline aluminum oxide layer of the alpha phase, Forming a mask on the metal layer, the mask defining a region in which the gate stack is to be formed; Sequentially etching the metal layer around the mask, the crystalline aluminum oxide layer on the alpha, the charge trap layer, and the tunneling film; And Removing the mask; and further comprising a charge trapping memory device. The method of claim 21, wherein the heat treatment of the resultant metal layer is performed after removing the mask. 21. The method of claim 20, wherein the metal layer is formed of any one of a TiCN layer, a Ru layer having a crystal direction of (0001), and a Rh2O3 layer. 25. The method of manufacturing a charge trapping memory device according to claim 24, wherein when the metal layer is an Rh2O3 layer, a heat treatment is performed to change the metal layer to conductivity. The method of claim 20, wherein the heat treatment is performed at 1000 to 1300 ° C. at normal pressure.

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