CN110010263A - A structure design method of hard, wear-resistant and conductive thin film material - Google Patents

Abstract

The present invention relates to the technical field of thin films, in particular to a method for structural design of a hard, wear-resistant and conductive thin film material; the present invention provides a free electron-rich solute by selecting a matrix having both a three-dimensional covalent bond network and free electrons and a solute rich in free electrons. A structural design method for hard, wear-resistant and conductive thin-film materials - a three-dimensional solid solution framework, the HfN(Ta/Ag) solid solution thin film prepared based on this three-dimensional solid solution framework overcomes the contradiction of "high hardness-high conductivity", The integration of high hardness, high wear resistance and high conductivity is obtained.

Description

A structure design method of hard, wear-resistant and conductive thin film material

technical field

The invention relates to the technical field of thin films, in particular to a structural design method of a hard, wear-resistant and conductive thin film material.

Background technique

Hardness, wear resistance and electrical conductivity are well-known material properties, and thin film materials with high hardness, high wear resistance and high electrical conductivity have high application value in the field of electrical testing. For example, stylus coatings for advanced inspection of integrated circuits and probe coatings for scanning probe microscopes, etc. Taking the probe coating of the conductive atomic force microscope as an example, high wear resistance and high hardness are used to ensure the sharpness of the probe during normal use, and to deal with the detection of high load and high hardness samples, and high conductivity is used to ensure large Detection range and accuracy. Therefore, it is necessary to design hard, wear-resistant and conductive thin-film materials.

However, it is very challenging to obtain hard, wear-resistant and conductive materials, and the main technical difficulties are as follows: (1) There is no material with both high hardness and high conductivity in natural materials. Highly conductive metals (Au, Ag, Cu, etc.) are rich in free electrons, but have low strength and hardness. In contrast, materials such as superhard diamond or cubic BN have extremely poor electrical conductivity. (2) There is a lack of theory to overcome the conflict between "high hardness and high conductance", and how to fundamentally realize the compatibility of these two properties has not yet been proposed. (3) It is not difficult to design and obtain hard, wear-resistant or conductive materials individually, but the integration of the three properties of high hardness, high wear resistance and high conductivity in the same material is difficult to achieve experimentally. Corresponding research full of challenge.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides a structure design method for a hard, wear-resistant and conductive thin film material, which aims to solve the above-mentioned three technical difficulties at the same time.

To achieve the above purpose, the present invention is achieved through the following technical solutions:

A structure design method for a hard, wear-resistant and conductive thin film material, characterized in that: the structure of the thin film material is a three-dimensional solid solution framework containing both a strong covalent bond network and abundant free electrons;

The three-dimensional solid solution framework has the following characteristics:

(1) The structural shape is three-dimensional;

(2) The parent body has a strong covalent bond network and unbound electrons;

(3) The solute is rich in free electrons.

Preferably, the precursor is selected from IVB, VB and VIB group transition metal compounds TMR.

Preferably, R in the transition metal compound TMR is B, C or N.

Preferably, the free electron concentration is 10 ²² cm ^-3 .

Preferably, there are two options for the solute. The first option is to select IV-VIB group transition metals. The difference between the atomic radius of the transition metal and the metal atomic radius of the parent is Δr<15%, and the crystal structure of the formed metal compound should be the same as that of the parent metal. The same or similar, the difference between the electronegativity of the formed metal compound and the electronegativity of the parent is ΔE<0.4; the second choice is to select the inert metal Ag or Au, etc., which needs to have a conductivity of 10 ⁷ S/m, and the inert metal The difference between the radius and the radius of the parent metal atom, Δr<15%.

Preferably, the precursor is HfN, the solute is Ta atoms, and the HfN(Ta) solid solution is prepared by reactive magnetron co-sputtering. In terms of the atomic percentage of each component, the N content is 50%, and the total amount of Hf and Ta is 50%. The content is 50%, and the atomic ratio [Ta/(Ta+Hf)] is controlled at 0.06-0.26.

Preferably, the precursor is HfN, the solute is Ag atoms, and the HfN(Ag) solid solution is prepared by reactive magnetron co-sputtering. According to the atomic percentage content of each component, the N content is 50%, and the total amount of Hf and Ag is 50%. The content is 50%, and the atomic ratio [Ag/(Ag+Hf)] is controlled at 0-0.06.

The present invention proposes a novel structural design, which successfully solves the above three problems, which are respectively as follows:

(1) In view of the first and second problems, considering that natural materials mainly based on metal bonds or covalent bonds cannot achieve the integration of high hardness and high conductivity, the present invention starts from the bonding origin of materials, and proposes a A three-dimensional solid solution framework with strong covalent bond network and rich free electrons, its parent is a transition metal compound with both TM-R covalent bonds and d orbital free electrons, and the solute is a group IV-VIB transition metal rich in free electrons and inert Metal. The solid solution combination of the precursor and the solute produces a solid solution strengthening effect and increases the average electron concentration and/or relaxation time of the system, which fundamentally overcomes the incompatibility of "high hardness-high conductance".

(2) For the third question, we construct the above-mentioned three-dimensional solid solution framework with HfN as the parent and Ta or Ag as the solute according to the novel structural design in (1) to realize the integration of various properties. Among them, the atomic radii and electronegativity of Ta and Hf are very close, and Ta and N can easily form a stable rock-salt structure; the atomic radii of Ag and Hf are very close, and the face-centered cubic structure of Ag is similar to that of HfN. Therefore, when an appropriate amount of Ta and Ag are introduced into HfN, it will replace part of the Hf atoms to form a solid solution of HfN(Ta) and HfN(Ag). Combined with various structural characterization methods (X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, etc.), the introduction ratios of Ta and Ag in TaHf and AgHf were determined to be 0.06- 0.26 and 0-0.06. Combined with four-probe resistance test, nanoindentation test, friction and wear test, first-principles calculation and Drude-Lorentz reflection spectrum fitting, we successfully prepared HfN with high hardness, high conductivity and low wear rate at the same time. (Ta) and HfN(Ag) solid solution, and the physical origin of the performance improvement was analyzed at the same time: the improvement of hardness is due to the solid solution strengthening effect, the improvement of wear resistance is due to the improvement of toughness, and the improvement of electrical conductivity is attributed to Ta and Ag has more valence electrons than Hf.

Beneficial effects of the present invention: The present invention provides a hard, wear-resistant and conductive material by selecting a matrix (TMR) with both a three-dimensional covalent bond network and free electrons and a solute (transition metal and inert metal) rich in free electrons. Structural design methods for thin-film materials—three-dimensional solid-solution frameworks. The HfN(Ta/Ag) solid solution thin film prepared according to this three-dimensional solid solution framework overcomes the contradiction of "high hardness and high conductivity", and obtains the integration of high hardness, high wear resistance and high conductivity. The structure design method provided by the invention provides theoretical support for the preparation of multifunctional thin film materials, and the obtained high performance thin film is an ideal candidate material for probe and stylus coating in the field of advanced electrical detection.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Figure 1(a) is the X-ray diffraction pattern of Example 1

Figure 1(b) is the X-ray diffraction pattern of Example 2

Figure 2(a) is a high-resolution transmission electron microscope and a selected area electron diffraction photograph of Example 1

Figure 2(b) is a selected area electron diffraction photograph of Example 2

Figure 3 is a hardness graph of Examples 1 and 2

Figure 4 is a conductivity graph of Examples 1 and 2

Figure 5 is a graph of the wear rate of Examples 1 and 2

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1:

A structure design method for a hard, wear-resistant and conductive thin film material, characterized in that: the structure of the thin film material is a three-dimensional solid solution framework containing both a strong covalent bond network and abundant free electrons;

The three-dimensional solid solution framework has the following characteristics:

(1) The structural shape is three-dimensional;

(2) The parent body has a strong covalent bond network and unbound electrons;

(3) The solute is rich in free electrons.

The precursors are IVB, VB and VIB transition metal compounds TMR.

R in the transition metal compound TMR is selected from B, C or N.

The free electron concentration is 10 ²² cm ^-3 .

There are two options for the solute. The second option is to select an inert metal such as Ag or Au, which needs to have a conductivity of 10 ⁷ S/m, and the difference between the radius of the inert metal and the radius of the parent metal atom Δr<15%.

The precursor is HfN, and the solute is Ag atoms. The HfN(Ag) solid solution is prepared by reactive magnetron co-sputtering. According to the atomic percentage of each component, the N content is 50%, and the total content of Hf and Ag is 50%. %, the atomic ratio [Ag/(Ag+Hf)] is controlled at 0-0.06.

The specific reactive magnetron co-sputtering is as follows:

A Hf target and an Ag target were co-sputtered in a mixed discharge gas of Ar and N2, using Si(001) and a glass substrate. The target-base distance, working pressure, substrate bias and temperature were fixed at 70mm, 1.0Pa, -160V and 200°C, respectively. The RF power of the Ag target, the DC power of the Hf target and the flow ratio of N2/Ar were kept at 50W, 150W and 2.8/80sccm, respectively. The substrates were ultrasonically cleaned with acetone, ethanol and distilled water, respectively, before being introduced into the sputtering vacuum chamber. The results of selected area electron diffraction, high-resolution transmission electron microscopy, and X-ray diffraction are consistent with each other, and it is consistent to prove that the HfN(Ag) film prepared under this condition has a rock-salt structure (Figs. 1(a) and 2(a)). The hardness, conductivity and wear rate of the films were 25.4GPa (Fig. 3), 3.48×10 ⁶ S/m (Fig. 4) and 1.03×10 ⁻⁵ mm ³ /(Nm) (Fig. 5 ), respectively.

Example 2:

A structure design method for a hard, wear-resistant and conductive thin film material, characterized in that: the structure of the thin film material is a three-dimensional solid solution framework containing both a strong covalent bond network and abundant free electrons;

The three-dimensional solid solution framework has the following characteristics:

(1) The structural shape is three-dimensional;

(2) The parent body has a strong covalent bond network and unbound electrons;

(3) The solute is rich in free electrons.

The precursors are IVB, VB and VIB transition metal compounds TMR.

R in the transition metal compound TMR is selected from B, C or N.

The free electron concentration is 10 ²² cm ^-3 .

There are two options for the solute. The first option is to select IV-VIB group transition metals. The difference between the atomic radius of the transition metal and the metal atomic radius of the parent is Δr<15%. The crystal structure of the formed metal compound should be the same or similar to that of the parent. The difference between the electronegativity of the metal compound and the electronegativity of the parent is ΔE<0.4.

The precursor is HfN, and the solute is Ta atom. The HfN(Ta) solid solution is prepared by reactive magnetron co-sputtering. According to the atomic percentage of each component, the N content is 50%, and the total content of Hf and Ta is 50%. %, the atomic ratio [Ta/(Ta+Hf)] is controlled at 0.06-0.26.

The specific reactive magnetron co-sputtering is as follows:

Hf targets and Ta targets were co-sputtered by radio frequency in a mixed discharge gas of Ar and N2, using Si(001) and glass substrates. The target-base distance, working pressure, substrate bias and temperature were fixed at 70mm, 1.0Pa, -160V and 200°C, respectively. The RF power of Ta target, the RF power of Hf target and the flow ratio of N2/Ar were kept at 150W, 150W and 2.0/80sccm, respectively. The substrates were ultrasonically cleaned with acetone, ethanol and distilled water, respectively, before being introduced into the sputtering vacuum chamber. The results of selected area electron diffraction and X-ray diffraction are consistent with each other, and it is consistent to prove that the HfN(Ta) film prepared under this condition has a rock-salt structure (Figs. 1(b) and 2(b)). The hardness, conductivity and wear rate of the films were 31.6 GPa (Fig. 3), 1.76×10 ⁶ S/m (Fig. 4) and 1.99×10 ⁻⁵ mm ^{3 /} (Nm) (Fig. 5 ), respectively.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (7)

1. a structure design method of hard, wear-resistant and conductive thin film material, it is characterized in that: the structure of thin film material is the three-dimensional solid solution framework that contains strong covalent bond network and abundant free electrons simultaneously; The three-dimensional solid solution framework has the following characteristics: (1) The structural shape is three-dimensional; (2) The parent body has a strong covalent bond network and unbound electrons; (3) The solute is rich in free electrons. 2 . The method for structural design of a hard, wear-resistant and conductive thin film material according to claim 1 , wherein the precursor is selected from IVB, VB and VIB transition metal compound TMR. 3 . 3 . The method for structural design of a hard, wear-resistant and conductive thin film material according to claim 2 , wherein the R in the transition metal compound TMR is selected from B, C or N. 4 . 4 . The method for structural design of a hard, wear-resistant and conductive thin film material according to claim 1 , wherein the free electron concentration is 10 ²² cm-3. 5 . 5. the structure design method of a kind of hard, wear-resistant and conductive thin film material as claimed in claim 1, is characterized in that: described solute has two kinds of choices, the first choice is to select IV-VIB group transition metal, transition metal The difference between the metal atomic radius and the parent metal atomic radius Δr<15%, the crystal structure of the formed metal compound should be the same or similar to that of the parent, and the difference between the electronegativity of the formed metal compound and the electronegativity of the parent ΔE<0.4; The second option is to select inert metals such as Ag or Au, which need to have an electrical conductivity of 10 ⁷ S/m, and the difference between the radius of the inert metal and the radius of the parent metal atom Δr<15%. 6. the structural design method of a kind of hard, wear-resistant and conductive thin film material as claimed in claim 5, it is characterized in that: parent body is HfN, and solute is Ta atom, adopts the method for reactive magnetron co-sputtering to prepare HfN ( Ta) solid solution, according to the atomic percentage content of each component, the N content is 50%, the total content of Hf and Ta is 50%, and the atomic ratio [Ta/(Ta+Hf)] is controlled at 0.06-0.26. 7. the structural design method of a kind of hard, wear-resistant and conductive thin film material as claimed in claim 5, it is characterized in that: parent body is HfN, and solute is Ag atom, adopts the method for reactive magnetron co-sputtering to prepare HfN ( Ag) solid solution, according to the atomic percentage content of each component, the N content is 50%, the total content of Hf and Ag is 50%, and the atomic ratio [Ag/(Ag+Hf)] is controlled at 0-0.06.