KR20110008852A - Charge trap flash type nonvolatile memory device - Google Patents

Abstract

PURPOSE: A charge trap type non-volatile memory device is provided to simultaneously improve a recording-erasing property and a data preservation property by adopting a trench structure. CONSTITUTION: A first tunneling insulation layer(32) is formed on a trench channel as a silicon oxide film. The thickness of the silicon oxide film is 2nm or less. A charge trapping layer is formed on a second tunneling insulation layer as a hafnium dioxide layer. The thickness of the hafnium dioxide layer is 10nm or less. The conduction band energy level of the hafnium dioxide layer is lower than that of the silicon oxide film, and the dielectric constant of the hafnium dioxide layer is more than that of the silicon oxide film. A gate electrode layer is formed on a blocking insulation film.

Description

Charge trap flash type nonvolatile memory device

The present invention provides a non-volatile memory device in which a tunneling insulating layer is formed of an asymmetric silicon oxide (SiO ₂ ) / silicon nitride (Si ₃ N ₄ ) stacked structure and a charge trap layer and a blocking insulating layer are formed of a high-k thin film. And a method for producing the same. More specifically, the present invention relates to a semiconductor fabrication capable of reading, writing, and storing electrical information, having a large capacity / high density, and capable of high-speed write / erase operations and long data retention.

The present invention is derived from a study performed by the Kwangwoon University Industry-Academic Cooperation Group with the support of the Ministry of Knowledge Economy. [Task unique number: 10029946, Title: Development of high reliability TBE-NFGM device]

Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices according to data storage methods. Volatile memory devices lose their stored data when their power supplies are interrupted. Volatile memory includes dynamic random access memory (DRAM) or static random access memory (SRAM). On the other hand, the nonvolatile memory device retains data even when power is not supplied.

Non-volatile memory devices are typical of flash memory devices, and technically, the advantages of DRAM and Read Only Memory (EPROM), as well as the advantages of EPROM (Erasable-Programmable Read-Only Memory) and EEPROM (Electrically Erasable-Programmable Read-Only Memory) It can be said that it has the advantages of. In particular, while the high density of DRAM and ROM, the storage contents can be rewritten as needed like EEPROM and DRAM, and the non-volatile characteristics of ROM and EEPROM are simultaneously maintained.

Such flash memory is widely used as a personal communication device such as a mobile phone that requires mobility to be portable, various small electronic devices such as USB memory, MP3, and PMP, and a data storage device such as a digital voice recorder or a memory card. have.

In particular, NAND (NOT-AND) flash memory, which is used in mobile phones, MP3s, digital cameras, and USB memories, is a representative nonvolatile memory device that solves a disadvantage of volatile operation of a DRAM (Dynamic Random Access Memory) device.

As such, flash memory has started to be used as a main memory device for portable devices due to its nonvolatile and low power consumption. In particular, the demand for flash memory is rapidly increasing as a mass storage medium such as digital home appliances due to its higher density than DRAM.

Therefore, in connection with such explosive demand, there is a demand for increasing storage capacity and improving performance. However, the conventional flash memory uses a floating gate made of polycrystalline silicon as a storage electrode, so when the integration is high, interference occurs between adjacent gates, and stored charge can move freely through the polycrystalline silicon. If a defect exists, all of the stored charges leak through the defect.

FIG. 1 illustrates a cross-sectional structure of a charge trapping nonvolatile memory device having a silicon-oxide-nitride-oxide-silicon (SONOS) type, which is a charge trapping nonvolatile memory manufactured to solve the above problems.

Referring to FIG. 1, a tunneling insulating film 22 made of SiO ₂ , a charge trap layer 23 made of Si ₃ N ₄ , a blocking insulating film 24 made of SiO ₂ , and a gate of polycrystalline silicon are formed on the semiconductor channel 20. The electrode layer 25 has a structure in which the electrode layers 25 are sequentially stacked.

The SONOS type charge trapping nonvolatile memory eliminates the interference problem in the floating gate memory of 40 nm or less and has a discontinuous trap, thereby improving the reliability of the memory device, but has the following disadvantages.

First, a tunneling insulating layer composed of a single layer of silicon oxide (SiO ₂ ) film has a direct tunneling phenomenon and a stress induced leakage currnet phenomenon when the thickness is reduced to improve the operation speed. Increasingly, data retention characteristics of more than 10 years that a nonvolatile memory should have cannot be secured. When the thickness of the tunneling insulating film composed of a single layer of silicon oxide film is increased in order to achieve data retention characteristics of 10 years or more, there is a disadvantage in that deterioration of data recording / erasing characteristics occurs.

Secondly, a blocking insulating film made of a silicon oxide film requires a high voltage to form charge in a channel because of low dielectric constant. In addition, due to the high voltage, an electron back injection phenomenon occurs from the gate electrode, which is canceled with the hole injected from the silicon substrate side for data erasing, so that the erase speed is lowered. Therefore, there is a problem that data is not completely erased.

FIG. 2A shows an energy band diagram in thermal equilibrium with respect to the cross-sectional structure in the A-A 'direction of the SONOS memory device of FIG. 1.

Referring to FIG. 2A, since the Fermi level is constant in the entire system, the energy bands of the semiconductor substrate doped with P-type and the control gate electrode doped with N-type are bent in the thermal equilibrium state as shown in FIG. .

Referring to FIG. 2B, a high voltage is applied to the semiconductor substrate as compared to the control gate electrode of the SONOS memory device in the erase mode. As shown in FIG. 2B, the thermal equilibrium is broken by an externally applied voltage so that the Fermi level E _fn of the electrode rises higher than the Fermi level of the semiconductor substrate, and the tunneling insulating layer 22 and the charge trap layer 23 are formed. The shape of the conduction band of the blocking insulating film 24 is modified.

In this erase operation, electrons stored in the charge trap layer 23 are tunneled through the tunneling insulating layer 22 and injected into the semiconductor substrate, thereby performing data erasing. However, since the hole injection is not easy and the work function of the polycrystalline silicon is low, the electrons are injected into the charge trapping layer by tunneling the blocking insulating film from the electrode, so that the threshold voltage is long and the data erasing time is long. A problem arises.

As these problems are solved, and as the memory devices are highly integrated, new device structures and manufacturing process technologies are required to simultaneously secure fast write / erase operations and data retention characteristics of 10 years or more.

Current non-volatile memory stores voltages that are very large. This causes defects in the tunneling oxide film due to the high voltage and causes the performance of the memory device to deteriorate. Therefore, it is expected that more serious problems will occur when the cell size of the flash memory becomes smaller.

In order to solve the above problems, by improving the material and structure of the tunneling insulating film of the conventional nonvolatile memory, a nonvolatile memory device and a method of manufacturing the same, which have a high speed at a low voltage at the time of writing and erasing and can improve data retention characteristics simultaneously. To provide.

In order to solve the above problems, a semiconductor memory device including a trench type gate structure including a trench channel having a source and a drain region formed on the substrate and etching the substrate to be lower than the source and drain regions. The trench gate structure of the device provided has a source drain drain (SDE) region of a sidewall spacer structure on the sidewall of the etched trench channel, and a thickness of 2 nm or less on the trench channel. A first tunneling insulating film formed of a silicon oxide film (SiO ₂ ), a silicon nitride film (Si ₃ N ₄ ) having a dielectric constant greater than that of the first tunneling insulating film and having a lower conduction band energy than the first tunneling insulating film (Si ₃ N ₄ ) on the first tunneling insulating film. A second tunneling insulating film formed on the second tunneling insulating film than the silicon nitride film Dodae energy level is low and the dielectric constant is a larger 10nm below the conduction band than that of the hafnium oxide layer on the charge trap layer, wherein the charge trap layer formed of a hafnium oxide film (HfO ₂₎ having a thickness of a high energy level is the valence band energy level lower 20nm A blocking insulating film formed of an aluminum oxide film (Al ₂ O ₃ ) having a thickness below, and a gate electrode layer formed on the blocking insulating film and having a work function of 4.5 eV or more.

Forming a trench channel by etching the semiconductor substrate after forming a source and a drain on the semiconductor substrate to solve another problem; Forming a source drain drain (SDE) region of a sidewall spacer structure on a side wall of the etched trench channel; Forming a first tunneling insulating layer formed of a silicon oxide layer (SiO ₂ ) having a thickness of 2 nm or less on the trench channel; Forming a second tunneling insulating film on the first tunneling insulating film, wherein the second tunneling insulating film is formed of a silicon nitride film (Si ₃ N ₄ ) having a dielectric constant greater than that of the first tunneling insulating film and having a lower conduction band energy and having a thickness of 3 nm or less; Forming a charge trap layer including a hafnium oxide layer (HfO ₂ ) having a lower dielectric constant than the silicon nitride layer (Si ₃ N ₄ ) and having a higher dielectric constant than the silicon nitride layer (Si ₃ N ₄ ) on the second tunneling insulating layer; Forming a blocking insulating layer on the charge trap layer including an aluminum oxide layer (Al ₂ O ₃ ) having a higher valence band energy level than the hafnium oxide layer (HfO ₂ ) and a low valence band energy level of 20 nm or less, and the blocking A method of manufacturing a charge trapping nonvolatile memory device is provided, including forming a gate electrode layer having a work function of 4.5 eV or more on an insulating film.

The nonvolatile memory employing the trench structure according to the present invention can be expected to improve the write / erase characteristics and the data retention characteristics at the same time.

Hereinafter, a charge trapping nonvolatile semiconductor device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to a client's or operator's intention or custom. Therefore, the definition should be based on the contents throughout this specification.

3 to 10 illustrate a method for fabricating a charge trapping type nonvolatile memory device having an asymmetric barrier having a SiO ₂ / Si ₃ N ₄ stack and an experimental result according to a preferred embodiment of the present invention. A schematic cross-sectional view and graph.

First, FIG. 3 shows a step by step method of manufacturing a charge trap type nonvolatile memory device according to the present invention.

In FIG. 3A, a doped silicon thin film is formed on the substrate 30. The substrate 30 may use a semiconductor substrate, such as a silicon substrate, and may use an SOI substrate or a polycrystalline silicon substrate. In this case, the doped silicon thin film 31 is formed of a polycrystalline silicon thin film doped with a high concentration of n-type impurities to a thickness of 5 to 100 nm by CVD (chemical vapor deposition) or sputtering, or doped with impurities by an epitaxy method. The single crystal silicon thin film can be formed.

In another embodiment, a shallow dopant-doped layer may be formed on the surface of the silicon semiconductor using ion implantation, plasma doping, or solid phase diffusion instead of the silicon thin film.

Referring to FIG. 3B, the doped silicon thin film 31 and the substrate 30 are etched to form trench regions on the silicon surface. In this case, the etching for forming the trench region may use a reactive ion etching (RIE) process using plasma or a wet etching method using a chemical solution.

Referring to FIG. 3C, an embodiment in which a sidewall spacer 31b is formed inside a trench region and used as a source drain extension region (SDE) is shown.

The sidewall spacer 31b has an extension region of the source and drain of the sidewall structure by an etchback process using an ion etching process (RIE) after growing a polycrystalline silicon or silicon epitaxy film doped with impurities. One structure is shown. At this time, the gate length can be adjusted by adjusting the thickness of the sidewall spacers, thus making it possible to fabricate an element having an ultra-fine gate length. In addition, by adjusting the concentration of the impurities doped in the sidewall spacer by controlling the electric field of the drain-side channel can also have the effect of suppressing the generation of hot carriers and short-channel effects.

In addition, as shown in FIG. 3C, after the silicon sidewall spacer is formed, a channel may be formed in a fine trench in the silicon channel portion through over etching by an ion etching process (RIE), which has an advantage of suppressing a short channel effect.

After forming the fine trench through silicon sidewall spacer etching, the silicon defect and the surface roughness inside the trench channel may be removed by hydrogen heat treatment at atmospheric pressure or reduced pressure at a temperature of 700 ° C. or higher.

Referring to FIG. 3D, a fine trench type channel region is formed between regions of the silicon sidewall spacers 31b doped to serve as SDE regions. The gate structure has a structure in which the first tunneling insulating layer 32, the second tunneling insulating layer 33, the charge trap layer 34, the blocking insulating layer 35, and the metal gate electrode 36 are sequentially stacked.

The first tunneling insulating film 32 is formed to a thickness where electrons or holes are easy to tunnel. The first tunneling insulating layer 32 forms SiO ₂ to a thickness of about 2 nm by a thermal oxidation method, a sputtering method or an ALD method at 700 to 800 ° C. in an oxygen (O ₂ ) gas atmosphere.

The second tunneling insulating layer 33 is formed of Si ₃ N ₄ to a thickness of about 3 nm by LPCVD method, sputtering method, sputtering method or ALD method at 700-800 ° C. using DCS (dichlorosilane) and NH ₃ gas. . Since the second tunneling insulating layer 33 has a larger dielectric constant than the first tunneling insulating layer and has a lower conduction band energy level and a valence band energy level, electrons or holes injected through the first tunneling insulating film are charged. It may be more easily injected into the trap layer 34.

The first tunneling insulating film 32 and the second tunneling insulating film 33 as a whole are referred to as a tunneling insulating film 37.

The charge trap layer 34 deposits a hafnium oxide layer (HfO ₂ ) having a lower dielectric constant than that of Si ₃ N ₄ and has a high dielectric constant in an ALD (atomic layer deposition) method or a sputtering method to a thickness of 5 to 10 nm. .

The charge trap layer may include at least one of a floating gate using polysilicon, a nano floating gate having a metal, a semiconductor, or oxide nanocrystals, or at least one of HfO ₂ , ZrO _2, and Si ₃ N ₄ . It may be formed to include.

Next, a blocking insulating layer 35 is deposited on the charge trap layer 34. The blocking insulating layer 35 deposits an aluminum oxide film (Al ₂ O ₃ ) having a higher conduction band energy level and lower valence band energy level than the hafnium oxide film HfO ₂ to a thickness of 10 to 20 nm by an ALD method or a sputtering method. The blocking insulating layer may have a large band gap, and may include at least one of a silicon oxide layer (SiO ₂ ) in addition to the aluminum oxide layer (Al ₂ O ₃ ).

The gate electrode 36 having a high work function of 4.5 eV or more, for example, TiN, TaN, Ni, Ir, Pt, or the like is formed on the blocking insulating layer 35 by 100 to 200 nm using a CVD or sputtering method. Deposit.

4 is a cross-sectional view illustrating a structure of a charge trap type nonvolatile memory device including a tunneling insulating layer having an ON stacked structure by forming a gate region through etching after forming a gate structure as shown in FIG. 3D.

After forming the gate structure as shown in FIG. 3d, regions other than the gate are removed by a dry etching method using an ion etching process or a wet etching method using a chemical solution. After forming the gate region, defects generated in the gate etching process may be removed through a subsequent heat treatment process at a low temperature of 300 ~ 500 ℃ in an atmosphere containing hydrogen.

5A and 5B show energy band diagrams in write and erase modes for the cross-sectional structure in the direction B-B 'in the device of FIG.

Referring to FIG. 5A, a high voltage is applied to the gate electrode in the write mode as compared with the semiconductor substrate of the memory device shown in FIG. 4. As shown in FIG. 5A, the thermal equilibrium is broken by an external applied voltage, and electrons are stored in the charge trap layer 34 through the tunneling insulating layer 37. At this time, the conduction band energy level barrier of the stacked tunneling insulating layer 37 is lowered, so that a larger flow of current can be expected.

Referring to FIG. 5B, a high voltage is applied to the semiconductor substrate in the erase mode compared to the gate electrode of the memory device illustrated in FIG. 4. In this erase mode, the electrons stored in the charge trap layer 34 are tunneled through the tunneling insulating layer 37 and injected into the semiconductor substrate to erase data. At the same time, as the valence band energy level barrier is lowered, the injection of holes into the inside of the charge trap layer 34 is facilitated, thereby improving the erase speed.

FIG. 6 shows the memory window according to the thickness of the Si ₃ N ₄ insulating film after the SiO ₂ tunnel oxide film is grown 2 nm and the Si ₃ N ₄ insulating film is deposited to a thickness of 2 to 6.7 nm.

6, it can be seen that charge trapping of the Si ₃ N ₄ insulating layer has a thickness of 4 nm or less, and charge trapping of the Si ₃ N ₄ insulating layer occurs from 5 nm or more. From the above results, it was confirmed that the trap of charge was generated in the Si ₃ N ₄ insulating layer, which is known as a trap-rich material, based on a specific thickness.

Therefore, as a preferred embodiment of the present invention, it is preferable to form the tunnel barrier by determining the thickness of the SiO ₂ tunnel oxide film 2 nm and the Si ₃ N ₄ insulating film 3 nm.

 7 is a diagram showing the write characteristics of the charge trap type nonvolatile memory device according to the present invention.

In FIG. 7, ONHA is a memory device having a SiO ₂ / Si ₃ N ₄ tunneling insulating film, an HfO ₂ charge trap layer, and an Al ₂ O ₃ blocking insulating film shown in FIG. 4, and OHA substitutes a single layer of SiO ₂ instead of a NON tunneling insulating film. And a HfO ₂ charge trap layer and an Al ₂ O ₃ blocking insulating film, and all of the gate electrodes are TiN.

Referring to FIG. 7, it can be seen that an ONHA memory device according to an embodiment of the present invention has a faster writing speed than an OHA device.

8 is a diagram illustrating erase characteristics of a charge trap type nonvolatile memory device according to the present invention.

Referring to FIG. 8, it can be seen that the ONHA memory device has a faster erase speed than the OHA device. This improvement in recording and erasing rate is due to not only the field sensitivity being improved by stacking the tunneling barrier but also the electric field concentrated in the tunneling barrier due to the application of the high-permittivity charge trap layer and the blocking insulating film.

9 is a view showing the durability of the charge trap type nonvolatile memory device according to the present invention. According to FIG. 9, it can be seen that a memory window of 3.51 V remains even after a total of 10 ⁵ write / erase operations. This is because deterioration of the tunneling insulating film is reduced by the low driving voltage and the high speed.

10 shows data retention characteristics of a charge trap type nonvolatile memory device according to the present invention.

After 10 years, it had a memory window of 1.27 V at room temperature. This is because the leakage current is reduced due to the increase in the physical thickness of the stacked tunneling insulating layer and the gate electrode having a high work function, thereby improving the data retention characteristics.

11 is a flowchart illustrating a method of manufacturing a charge trap type nonvolatile memory device according to the present invention.

First, a source and a drain are formed on a semiconductor substrate (1110).

Thereafter, the semiconductor substrate is etched to form a trench channel (1120).

When the trench channel is formed, a source drain drain (SDE) region having a sidewall spacer structure is formed on the side wall of the trench channel (1130). This sidewall spacer structure determines the characteristics of the semiconductor device according to the present invention.

When the source and drain extension regions of the sidewall space structure are formed, a first tunneling insulating layer made of silicon oxide (SiO ₂ ) having a thickness of 2 nm or less is formed on the trench channel (1140).

A second tunneling insulating layer including a silicon nitride layer (Si ₃ N ₄ ) having a higher dielectric constant than the first tunneling insulating layer and having a lower conduction band energy than 4 nm or less is formed on the first tunneling switching layer (1150). In this way, a tunneling insulating film composed of the first tunneling insulating film and the second tunneling insulating film was formed.

On the tunneling insulating layer, a charge trap layer including a hafnium oxide layer (HfO ₂ ) having a lower dielectric constant than the silicon nitride layer (Si ₃ N ₄ ) and a larger dielectric constant is formed (1160).

On the charge trap layer, a blocking insulating layer made of aluminum oxide (Al ₂ O ₃ ) having a thickness of 20 nm or less is formed while the energy level of the conduction band is higher than that of the hafnium oxide (HfO ₂ ) (1170).

When the gate electrode layer having a work function of 4.5 eV or more is formed 1180 on the blocking insulating layer, a basic structure of the device is formed.

As described above, in the present invention, a low driving voltage and fast write / erase characteristics are achieved by using a stacked SiO ₂ / Si ₃ N ₄ tunneling insulating layer instead of a single layer of SiO ₂ , a charge trap layer having high dielectric constant, and a blocking insulating layer. It was confirmed, thereby achieving an improvement in durability.

As described above, the present invention has been described based on the preferred embodiments, but these embodiments are intended to illustrate the present invention, not to limit the present invention, so that those skilled in the art to which the present invention pertains can practice the above without departing from the technical spirit of the present invention. Various changes, modifications or adjustments to the example will be possible. Therefore, the protection scope of this invention will be limited only by the appended claims, and should be construed as including all changes, modifications or adjustments.

1 is a cross-sectional view of a structure of a charge trapping nonvolatile memory device having a silicon-oxide-nitride-oxide-silicon (SONOS) type according to the prior art.

FIG. 2 is an energy band diagram in thermal equilibrium with respect to the cross-sectional structure in the A-A 'direction of the SONOS memory element of FIG.

3 is a view showing a method for manufacturing a charge trap type nonvolatile memory device according to the present invention.

FIG. 4 is a cross-sectional view illustrating a structure of a charge trapping nonvolatile memory device including a tunneling insulating layer having a NON stacked structure by forming a gate region through etching after forming the gate structure as shown in FIG. 3D.

5A and 5B show energy band diagrams in write and erase modes for the cross-sectional structure in the direction B-B 'in the device of FIG.

6 is a view showing a memory window according to the thickness of the Si ₃ N ₄ insulating film according to the present invention.

7 is a diagram showing the write characteristics of the charge trap type nonvolatile memory device according to the present invention.

8 is a diagram illustrating erase characteristics of a charge trap type nonvolatile memory device according to the present invention.

9 is a view showing the durability of the charge trap type nonvolatile memory device according to the present invention.

10 is a view showing data retention characteristics of a charge trap type nonvolatile memory device according to the present invention.

11 is a flowchart illustrating a method of manufacturing a charge trap type nonvolatile memory device according to the present invention.

Claims (8)

12. A semiconductor memory device comprising a semiconductor substrate, a trench type gate structure including a trench channel having a source and a drain region formed on the substrate and etching the substrate to form a lower channel than the source and drain regions. Is A source drain drain (SDE) region of a sidewall spacer structure on a side wall of the etched trench channel, A first tunneling insulating film formed of a silicon oxide film (SiO ₂ ) having a thickness of 2 nm or less on the trench channel, A second tunneling insulating film formed on the first tunneling insulating film with a silicon nitride film (Si ₃ N ₄ ) having a dielectric constant greater than that of the first tunneling insulating film and having a lower conduction band energy and having a thickness of 4 nm or less; A charge trap layer formed of a hafnium oxide layer (HfO ₂ ) having a lower conductance band energy level and a higher dielectric constant than that of the silicon nitride layer on the second tunneling insulating layer; A blocking insulating film formed on the charge trap layer by an aluminum oxide film (Al ₂ O ₃ ) having a higher energy level than the hafnium oxide film and having a lower valence band energy level than 20 nm; And a gate electrode layer formed on the blocking insulating layer and having a work function of 4.5 eV or more. 2. The trench of claim 1, wherein the trench channel is formed to be lower than a source drain extension (SDE) region of the sidewall spacer structure, and the first tunneling insulating layer and the second tunneling insulating layer are asymmetrical barriers. A charge trap type nonvolatile memory device, characterized in that the structure. The method of claim 1, wherein the charge trap layer is Floating gate using polysilicon, Nano floating gates having metal, semiconductor or oxide nanocrystals, or A charge trapping nonvolatile memory device comprising at least one of a charge trap layer including at least one of HfO ₂ , ZrO _2, and Si ₃ N ₄ . The charge trap type nonvolatile memory device of claim 1, wherein the gate electrode layer is formed of a material of TiN, TaN, Ni, Ir, or Pt. Forming a trench channel by etching the semiconductor substrate after forming a source and a drain on the semiconductor substrate; Forming a source drain drain (SDE) region of a sidewall spacer structure on a side wall of the etched trench channel; Forming a first tunneling insulating layer formed of a silicon oxide layer (SiO ₂ ) having a thickness of 2 nm or less on the trench channel; Forming a second tunneling insulating film on the first tunneling insulating film, the second tunneling insulating film including a silicon nitride film (Si ₃ N ₄ ) having a dielectric constant greater than that of the first tunneling insulating film and having a lower conduction band energy and having a thickness of 4 nm or less; Forming a charge trap layer including a hafnium oxide layer (HfO ₂ ) having a lower dielectric constant than the silicon nitride layer (Si ₃ N ₄ ) and having a higher dielectric constant than the silicon nitride layer (Si ₃ N ₄ ) on the second tunneling insulating layer; Forming a blocking insulating layer on the charge trap layer including an aluminum oxide film (Al ₂ O ₃ ) having a higher valence band energy level than a hafnium oxide film (HfO ₂ ) and a low valence band energy level; And forming a gate electrode layer having a work function of 4.5 eV or more on the blocking insulating layer. 6. The charge trapping ratio of claim 5, further comprising forming the trench channel lower than a source drain extension (SDE) region of the sidewall spacer structure. Method of manufacturing volatile memory device. The method of claim 5, wherein the forming of the charge trap layer Floating gate using polysilicon, Nano floating gates having metal, semiconductor or oxide nanocrystals, or A charge trapping type nonvolatile memory device comprising: at least one of a charge trap layer including at least one of HfO ₂ , ZrO _2, and Si ₃ N ₄ . The method of claim 5, wherein the gate electrode layer is formed of a material of TiN, TaN, Ni, Ir, or Pt.

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