KR20200005487A - A method for manufacturing chalcogenide, and electronic device contaning the same - Google Patents

Abstract

The present invention relates to a method for identifying the carbon concentration doped in a chalcogenide material and, more specifically, to a method for identifying the current carbon doping concentration using an elemental reactivity difference which changes as the carbon doping concentration of chalcogenide in X-ray photoelectron spectroscopy (XPS) is changed. At this time, since a measurement range of carbon doped chalcogenide does not include 284.5 eV representing C-C bond, the method of the present invention has the same XPS characteristics regardless of contamination of devices and materials and may be applied to various environments. According to the present invention, the doping concentration can be economically and stably identified and determined for the carbon doped chalcogenide material and device.

Description

A manufacturing method of chalcogenide and an electronic device including the same {A METHOD FOR MANUFACTURING CHALCOGENIDE, AND ELECTRONIC DEVICE CONTANING THE SAME}

The present invention relates to doping, and more particularly, to achieve a precise concentration of doping using the difference in the reactivity of carbon (C) to the chalcogenide compound, a method of producing carbon-doped chalcogenide using the same and It relates to an electronic device comprising the same.

Chalcogenide has the property of rapidly changing into a crystalline and amorphous state when heated. Recording in DVD-RAM (using reflectance difference) or PRAM (using resistance difference) with two states set to 1 and 0, respectively, in the crystalline state with high optical reflectivity and low electrical resistance, whereas in amorphous state with low reflectivity and high electrical resistance I use it as a substance. The most representative chalcogenide compound used for DVD-RAM and the like is Ge ₂ Sb ₂ Te ₅ .

Carbon doped Ge ₂ Sb ₂ Te ₅ is the most representative of several materials attempted to increase the stability of Ge ₂ Sb ₂ Te ₅ . Ge ₂ Sb ₂ Te ₅ is changed to the crystalline and amorphous state with temperature, and can express 0 and 1 by using the resistance difference generated at this time, and many studies have been conducted as representative materials of next generation PCRAM devices. As an attempt to improve the device performance of Ge ₂ Sb ₂ Te _5, the most widely used method is doping of other elements, and thus the thermal stability, device switching speed, durability, amorphous and crystalline resistance of Ge ₂ Sb ₂ Te ₅ . The characteristics such as differences vary.

Carbon-doped Ge ₂ Sb ₂ Te ₅ has been studied a lot because it can significantly improve the thermal stability and durability of the material without harming other properties. The concentration of carbon doped in Ge ₂ Sb ₂ Te ₅ is preferentially bonded to Ge when the concentration is 8.5% or less, and then to Sb. This property can be used to determine the exact doping concentration of carbon for carbon doping below 8.5%.

Chalcogenide requires a process of accurately determining and reconfirming the doping concentration of carbon because the device and material properties are significantly different when the doping concentration of carbon is slightly different. However, in the conventional X-ray photoelectron spectroscopy (XPS) method, when using the C1s orbital peak, the carbon is mixed in the dust of the air due to the characteristics of carbon.

In addition, even if the device management is perfectly done in a vacuum state, the measurement device itself is likely to have carbon, it is difficult to meet the carbon concentration within the desired error in the low concentration doping, and thus repeatedly test the doping concentration of the device Unnecessary effort is consumed in the process.

The present invention is to solve the above-mentioned problems of the prior art, the object of the present invention is to stably and quickly determine the concentration of carbon doped in Ge ₂ Sb ₂ Te ₅ stably without mixing with other materials or surrounding environment It provides a way to check.

Another object of the present invention is to provide a method for easily preparing chalcogenide using the above method and an electronic device including the same.

In order to solve this problem, an embodiment of the present invention provides a method of confirming doping concentration by analyzing an energy region other than the C1s orbital of X-ray photoelectron spectroscopy (XPS). That is, it is different from the conventional method using the C1s peak appearing at 284.5 eV. This is because when measuring the concentration of the doped carbon through the C1s peak it is inevitable to influence such dust or organic matter.

Looking at the properties of Ge ₂ Sb ₂ Te ₅ as an embodiment of the present invention, the combination of C, Ge, and Sb is selectively made according to the doping concentration. C prefers binding to Ge up to about 8.5% doping. However, when the doping concentration is increased to more than 8.5% it will start to combine with Sb. By analyzing the peak change of Ge3d and Sb4d according to this can be confirmed roughly the concentration of the current doped carbon.

If the doped carbon does not exceed 8.5%, the change in Ge3d peak is noticeable and the Sb4d peak shows little change. On the other hand, if the carbon concentration exceeds 8.5%, Ge-C bonds no longer occur, but instead Sb-C bonds occur, the shape of the Sb4d peak begins to change. This allows the doping concentration to be accurately determined at Ge ₂ Sb ₂ Te ₅ carbon doping of 8.5% or less. Details of the analysis method are included in the detailed description including the drawings.

In addition, the present invention can specify only the concentration of carbon bound to a specific chalcogenide material through XPS even when other materials other than carbon doped chalcogenide are mixed to realize the multi-level. Can be.

One aspect of the present invention, in the method for measuring the carbon concentration doped in chalcogenide by using X-ray photoelectron spectroscopy (XPS), the peak corresponding to the MC bond based on the maximum value of the peak corresponding to the MC bond It provides a method of measuring the concentration of carbon doped in chalcogenide by measuring the ratio of height. M is one of the components of the chalcogenide but not carbon.

In one embodiment, the chalcogenide may be Ge ₂ Sb ₂ Te ₅ , M may be Ge or Sb.

In one embodiment, the maximum value of the peak corresponding to the M-C bond may have a carbon concentration of 7.5 to 10% or 15 to 20% of the total number of atoms of the chalcogenide.

Another aspect of the invention, the step of depositing a metal, chalcogen and carbon on the substrate to form a carbon-doped chalcogenide thin film, by measuring the carbon concentration of the thin film by the method described above Provided is a method of preparing carbon doped chalcogenide that determines the amount of deposition.

In one embodiment, the deposition is performed by one or more methods selected from the group consisting of physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, evaporation, electron beam evaporation, atomic layer deposition, and molecular beam epitaxy deposition. Can be.

In one embodiment, the metal may be one or more selected from the group consisting of Bi, In, Cu, Ge, Sb, Si and Sn.

Another aspect of the invention, the carbon doped chalcogenide, the chalcogenide has a peak intensity of 33.5 ± 0.5 eV binding energy measured using XPS (X-ray photoelectron spectroscopy) binding energy 31.5 Provides an electronic device with a peak intensity of ± 0.5 eV.

In one embodiment, the chalcogenide may be Ge ₂ Sb ₂ Te ₅ .

In one embodiment, the carbon concentration doped in the chalcogenide may be more than 8.5% based on the total number of atoms of the chalcogenide.

According to an embodiment of the present invention, the concentration of carbon doped in Ge ₂ Sb ₂ Te ₅ stably regardless of the mixed environment or surrounding environment for carbon doping of 8.5% or less on an atomic basis. It is expected that similar phenomena will occur in other chalcogenide materials. Ultimately, in the device fabrication process of the existing chalcogenide, the manufacturing time is significantly shortened.

It is to be understood that the effects of the present invention are not limited to the above effects, and include all effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 shows (a) chalcogenide material Ge ₂ Sb ₂ Te ₅ , (b) 5% carbon doped chalcogenide material Ge ₂ Sb ₂ Te ₅ and (c) 10% according to an embodiment of the invention A graph showing XPS measurement results of a carbon-doped chalcogenide material Ge ₂ Sb ₂ Te ₅ ;
FIG. 2 is a graph showing the results of XPS measurements with varying phase and doped carbon concentration of the chalcogenide material Ge ₂ Sb ₂ Te ₅ ;
3 is a graph showing the correlation between temperature and resistance according to the carbon concentration doped in the chalcogenide material Ge ₂ Sb ₂ Te ₅ .

Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The basic principle of the present invention is to identify and control the concentration of the doped carbon using the differentiation of the multi-element chalcogenide according to the concentration of the doped carbon. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Conventional methods confirm the carbon concentration by measuring the value of the C1s orbital peak with XPS when doping carbon to chalcogenide. However, an error in measured values occurs due to carbon present in the dust in the air or carbon present in the measuring device. In particular, when doping carbon for application to various devices, it is difficult to realize and reproduce desired characteristics. The properties of chalcogenide are very sensitive to carbon concentration, and the problem due to this error is more pronounced at low concentrations of doping, and excessive trial & error was required to dope the carbon concentration of desired characteristics.

On the other hand, the method according to an aspect of the present invention, in the method for measuring the carbon concentration doped in chalcogenide using X-ray photoelectron spectroscopy (XPS), MC based on the maximum value of the peak corresponding to the MC bond The concentration of carbon doped in chalcogenide can be determined by measuring the ratio of the peak height corresponding to the bond. M is one of the components of the chalcogenide but not carbon.

Since the method determines the carbon concentration by measuring the ratio of the M-C bond, the error due to the carbon present in the chalcogenide surface, the atmosphere or the measuring instrument does not occur, so that the concentration can be measured more precisely.

For example, the chalcogenide may be Ge ₂ Sb ₂ Te ₅ , and M may be Ge or Sb, but is not limited thereto.

The maximum value of the peak corresponding to the M-C bond may be a value of 7.5 to 10% or 15 to 20% of the carbon concentration based on the total number of atoms of the chalcogenide. Since each component of the chalcogenide is different from carbon, one component reacts with carbon first to form a bond with carbon, and then another component reacts with carbon to form a bond.

For example, when the chalcogenide is Ge ₂ Sb ₂ Te _5, Ge, which is highly reactive with carbon, first forms a Ge-C bond, and the value of the XPS binding energy peak having a carbon concentration of about 7.5 to 10% may be the maximum. have. Alternatively, at a carbon concentration of 10 to 25%, 12.5 to 22.5%, or 15 to 20%, Sb may react with carbon to form Sb-C bonds to represent the maximum value of the XPS binding energy peak. The carbon concentration representing the maximum value of these peaks may be determined according to the type of chalcogenide or the type of M.

Method for producing a carbon doped chalcogenide according to another aspect of the present invention, by depositing a metal, chalcogen and carbon on a substrate to form a carbon-doped chalcogenide thin film; Deposition of the carbon may be determined by measuring the carbon concentration of the thin film.

As described above, by measuring the carbon concentration by the above method to prepare carbon doped chalcogenide, chalcogenide doped with the correct amount of carbon may be prepared.

The deposition may be performed by physical vapor deposition (PVD), chemical vapor deposition (CVD), sputtering, pulsed laser deposition (PLD), thermal evaporation, or electron beam evaporation. The method may be performed by one or more methods selected from the group consisting of electron beam evaporation, atomic layer deposition (ALD), and molecular beam epitaxy (MBE).

The metals, chalcogens and carbon may be deposited simultaneously or alternately into the substrate at each deposition source. For example, sputtering to a target comprising at least one metal and at least one chalcogen and reactively doping carbon can be doped with methane or acetylene.

The metal may be at least one selected from the group consisting of Bi, In, Cu, Ge, Sb, Si, and Sn, and the chalcogen may be at least one of Group 16 elements except oxygen such as S, Se, and Te.

After the deposition, the thermal treatment may be further performed by annealing, pulsed laser irradiation, or applying current.

In another aspect of the present invention, an electronic device includes carbon-doped chalcogenide, and the chalcogenide has a peak intensity of 33.5 ± 0.5 eV in binding energy measured using X-ray photoelectron spectroscopy (XPS). The binding energy may be higher than the peak intensity of 31.5 ± 0.5 eV.

The chalcogenide may be Ge ₂ Sb ₂ Te ₅ , but is not limited thereto.

The carbon concentration doped in the chalcogenide may be 8.5% or more based on the total number of atoms of the chalcogenide. The upper limit of the carbon concentration may be 20% or less, 17.5% or less, 15% or less, or 12.5% or less, but is not limited thereto.

The electronic device may be manufactured using the above-described method and manufacturing method.

The electronic device stably maintains the phase even at 400 ° C. or higher, which is a processing temperature of a typical BEOL process, which forms metal wiring and input / output terminals on a MOSFET (MOS field-effect transistor). It may have a semiconducting resistivity characteristic in which the resistance is reduced. In particular, the electronic device may be significantly superior in thermal stability compared to the conventional electronic device.

Hereinafter, embodiments of the present invention will be described in more detail. However, the following experimental results are described only representative experimental results of the above embodiments, the scope and content of the present invention by the examples and the like can not be interpreted to be reduced or limited. The effects of each of the various embodiments of the invention, which are not explicitly set forth below, will be described in detail in that section.

Comparative example

Ge ₂ by cross-depositing Ge, Sb and Te on SiO ₂ (200 nm) / Si (100 nm) substrates by ion beam sputtering deposition (IBS) at a base pressure of 1 × 10 ^-8 torr or less A Sb ₂ Te ₅ thin film was prepared. The growth temperature was maintained at room temperature (25 ° C.) for the preparation of the amorphous membrane, and Ar ⁺ was introduced at a pressure of 6.5 × 10 ⁻⁵ torr to use Ar ⁺ as an ion source.

Example

Deposition of Ge, Sb and Te on SiO ₂ (200 nm) / Si (100 nm) substrates by ion beam sputtering deposition (IBS) at a base pressure of 1 × 10 ^-8 torr or less. Methane (CH ₄ ) was deposited to prepare a carbon-doped C-Ge ₂ Sb ₂ Te ₅ thin film. The growth temperature was maintained at room temperature (25 ° C.) for the preparation of the amorphous membrane, and Ar ⁺ was introduced at a pressure of 6.5 × 10 ⁻⁵ torr to use Ar ⁺ as an ion source. The content of the doped carbon was measured according to the method of the experimental example described below to determine the flow rate of methane.

Experimental Example 1

XPS measurement of Ge ₂ Sb ₂ Te ₅ which is a chalcogenide material prepared in Comparative Examples and Examples was analyzed. Peaks of Ge3d and Sb4d are separated into peaks of existing Ge ₂ Sb ₂ Te ₅ and newly generated peaks of Ge-C and Sb-C through doping. Herein, the doped carbon concentration was confirmed by comparing the heights of the peaks corresponding to Ge-C and Sb-C. The peak height corresponding to Ge-C showed a maximum value around 8.5% of carbon concentration.

1 (a) is the XPS measurement result of Ge ₂ Sb ₂ Te ₅ according to an embodiment of the present invention. The measured energy range is expressed from 24 eV to 37 eV and the energy range includes the orbitals of Ge3d and Sb4d. Peaks corresponding to Ge3d are separated into Tetrahedral bonds (30.04 eV) and Octahedral bonds (29.66 eV) according to two different bonding methods of Ge in the Ge ₂ Sb ₂ Te ₅ structure. In addition, the peak corresponding to Sb4d corresponds to an energy of 32.57 eV.

FIG. 1 (b) is a graph showing XPS measurements of the same energy range after Ge ₂ Sb ₂ Te ₅ based on 5% carbon doping, and FIG. 1 (c) shows Ge ₂ Sb ₂ Te ₅ based on atomic number. After 10% carbon doping, the XPS plot measures the energy range in the same range. In FIG. 1 (b) and FIG. 1 (c), since new atomic bonds are formed by the doping of carbon, new items are added in the graph fitting process. Ge-C bonds correspond to 31.30 eV and Sb-C bonds correspond to 33.47 eV. Since the electronegativity of carbon is stronger than Te, when the Ge-Te bond is replaced by the Ge-C bond and the Sb-Te bond is replaced by the Sb-C bond, the XPS peak appears in the higher energy region than before.

Referring to FIG. 1 (b), a peak corresponding to Ge-C binding exists in the XPS graph but no peak corresponding to binding of Sb-C exists. This is because when carbon is doped below 8.5%, it preferentially bonds with Ge and hardly bonds with Sb.

On the other hand, the XPS graph of FIG. 1 (c) shows that Ge-C bonds and Sb-C bonds exist simultaneously when 10% of carbon is doped. It was confirmed that additional Ge-C bonds were not formed even when the concentration of carbon exceeded 8.5%. Through this, if the carbon doping is less than 8.5%, the doping concentration of the carbon can be confirmed through the height of the Ge-C peak. For example, the Ge-C peak height on the fitted graph at 4.25% carbon doped Ge ₂ Sb ₂ Te ₅ has half the Ge-C peak height of Ge ₂ Sb ₂ Te ₅ doped with 8.5% carbon. That is, the concentration of C can be confirmed for all carbon doping concentrations of 8.5% or less.

In this example, a carbon doped Ge ₂ Sb ₂ Te ₅ with a sputter was grown and transferred to in-situ to measure the XPS. When determining the doping concentration based on the Ge-C peak height of the XPS, even if the sample is contaminated with dust or organic matter, it is preferred from the perspective of time and economy. This can effectively replace the identification using the C1s peak of XPS, or the identification using the EDS of SEM and TEM.

Experimental Example 2

The chalcogenide material Ge ₂ Sb ₂ Te ₅ prepared in Comparative Examples and Examples of amorphous, face-centered cubic (fcc), hexagonal close-packing (hcp) XPS measurement to confirm the phase change characteristics according to the crystal structure is shown in Figure 2 the results.

2 (a1) to 2 (a3) are XPS graphs according to the carbon doping concentration of amorphous Ge ₂ Sb ₂ Te ₅ , and FIGS. 2 (b1) to 2 (b3) are carbon doping concentrations of fcc Ge ₂ Sb ₂ Te ₅ Figure 2 (c1) to 2 (c3) is a XPS graph according to the carbon doping concentration of Ge ₂ Sb ₂ Te ₅ mixed with fcc and hcp.

Analysis of FIG. 2 in the same manner as in Experimental Example 1, irrespective of the crystal structure of the chalcogenide, preferentially binds to Ge and hardly binds to Sb when the carbon is doped to less than 8.5%. Thus, the above-described method can measure the carbon concentration irrespective of contamination of the device and material in all crystal structures in the same way. In addition, since it is independent of the crystal structure, the carbon concentration can be accurately measured regardless of the conditions such as the temperature at the time of measurement.

Experimental Example 3

The change in resistance according to the temperature of Ge ₂ Sb ₂ Te ₅ , the chalcogenide material prepared in Comparative Examples and Examples, was measured and the results are shown in FIG. 3.

Referring to FIG. 3, it can be seen that the phase change temperature increases according to the doped carbon concentration. The first phase change temperature, changing from amorphous to fcc, was 150 ° C. in Ge ₂ Sb ₂ Te ₅ (FIG. 3 (a)) of the comparative example, and at a carbon concentration of 5% Ge ₂ Sb ₂ Te ₅ (FIG. 3 (b)) of the example. It gradually increases with carbon concentration from 200 ° C. to 250 ° C. in the carbon concentration of 10% Ge ₂ Sb ₂ Te ₅ (FIG. 3 (c)). The second phase change temperature from fcc to hcp was 300 ° C. in Ge ₂ Sb ₂ Te ₅ of the comparative example, carbon concentration 5% Ge ₂ Sb ₂ Te ₅ in the example, 350 ° C. in the example, and 10% Ge ₂ Sb ₂ Te in the carbon concentration of the example. ₅ to 400 ° C or higher.

Analyzing the slope between the temperature and the resistance, that is, the resistivity, shows the slope characteristic of the semiconducting after the first phase change, but changes to the conductor slope of the metallic after the second phase change. However, only Ge ₂ Sb ₂ Te ₅ having a carbon concentration of 10% shown in FIG. 3C maintains a semiconducting slope and is an effect of Sb-C bonds generated at a carbon concentration of 8.5% or more.

The Ge ₂ Sb ₂ Te ₅ with a carbon concentration of 10% maintains the fcc phase stably even at a general process processing temperature of 400 ° C. or higher, and has a semiconducting resistivity characteristic in which resistance decreases as temperature increases, which is advantageous for electronic devices. Applicable

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the invention is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention.

Claims (10)

In the method of measuring the carbon concentration doped in chalcogenide using X-ray photoelectron spectroscopy (XPS),
To determine the carbon concentration doped in chalcogenide by measuring the ratio of the peak height corresponding to the MC bond based on the maximum value of the peak corresponding to the MC bond:
M is one of the components of the chalcogenide but not carbon. The method of claim 1,
Said chalcogenide is Ge ₂ Sb ₂ Te ₅ . The method of claim 2,
M is Ge or Sb. The method of claim 2,
The maximum value of the peak corresponding to the MC bond is a carbon concentration of 7.5 to 10% or 15 to 20% of the total atomic number of the chalcogenide. And depositing metal, chalcogen, and carbon on the substrate to form a carbon doped chalcogenide thin film.
The method of claim 1, wherein the carbon concentration of the thin film is measured by the method of claim 1 to determine the deposition amount of the carbon doped chalcogenide. The method of claim 5,
The deposition is performed by one method selected from the group consisting of physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, evaporation, electron beam evaporation, atomic layer deposition, molecular beam epitaxy deposition, and combinations of two or more thereof. Method for preparing carbon doped chalcogenide. The method of claim 5,
Wherein said metal is at least one selected from the group consisting of Bi, In, Cu, Ge, Sb, Si, or Sn. Comprising carbon doped chalcogenides,
The chalcogenide is an electronic device having a peak intensity of 33.5 ± 0.5 eV of binding energy measured using XPS (X-ray photoelectron spectroscopy) higher than the peak intensity of 31.5 ± 0.5 eV of binding energy. The method of claim 8,
The chalcogenide is Ge ₂ Sb ₂ Te ₅ Electronic device. The method of claim 8,
The concentration of carbon doped in the chalcogenide is 8.5% or more based on the total number of atoms of the chalcogenide.

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