Thermally stable thin film resistor

Abstract

A thermally stable thin film resistor is provided to solve the problem of low stability of the conventional resistors at high temperatures. The thin film resistor includes a substrate, a resistance layer stacked on the substrate, and a functional layer stacked on the resistance layer. The temperature coefficient of resistance of the material of the resistance layer is positive, and the temperature coefficient of resistance of the material of the functional layer is negative. The difference between the absolute value of the temperature coefficient of resistance of the material of the resistance layer and the absolute value of the temperature coefficient of resistance of the material of the functional layer is less than or equal to

Description

Technical Field

[0001] This invention relates to an electronic component, and more particularly to a thermally stable thin-film resistor that reduces the temperature resistivity and maintains a stable resistance value. Prior Technology

[0002] Thin-film resistors are resistors deposited on wafers at nanometer-level thicknesses during thin-film or semiconductor manufacturing processes. The resistance value of thin-film resistors can be precisely controlled by adjusting the thickness and selecting materials. Therefore, thin-film resistors are often used in precision instruments such as medical instruments, industrial computers, and automobiles.

[0003] The temperature coefficient of resistance (TCR) of a conventional resistor is the ratio of its resistivity to the change in temperature. In other words, in a temperature-changing operating environment, a higher TCR results in a more unstable resistance value. A positive TCR means that increasing temperature increases the resistance value, while a negative TCR means that increasing temperature decreases the resistance value. Conventional thin-film resistors are commonly used in precision instruments and products requiring high safety. Therefore, conventional thin-film resistors need to maintain a stable and reliable resistance value in environments with varying temperatures. However, when conventional thin-film resistors are used as heating elements or under extreme high / low temperature conditions, the resistance value can still change significantly due to drastic temperature changes, thus affecting the quality and thermal stability of electronic components.

[0004] In view of this, there is indeed a need to improve upon conventional thin-film resistors. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a thermally stable thin-film resistor whose temperature resistivity can be adjusted to approach zero.

[0006] A secondary objective of this invention is to provide a thermally stable thin-film resistor that can improve the reliability and thermal stability of electronic components.

[0007] The use of the quantifiers "a" or "an" for the elements and components described throughout this invention is for convenience and to provide the general meaning of the scope of the invention; in this invention, it should be interpreted as including one or at least one, and the concept of a single also includes the case of a plural, unless it clearly means otherwise.

[0008] The thermally stable thin-film resistor of the present invention comprises: a substrate; a resistive layer stacked on the substrate, wherein the temperature resistivity of the material of the resistive layer is positive; and a functional layer stacked on another surface of the resistive layer opposite to the substrate, wherein the temperature resistivity of the material of the functional layer is negative, the difference between the absolute value of the temperature resistivity of the material of the resistive layer and the absolute value of the temperature resistivity of the material of the functional layer is less than or equal to 500 ppm / ℃, and the thickness ratio of the resistive layer to the functional layer is between 1:7 and 7:1.

[0009] Accordingly, the thermally stable thin-film resistor of the present invention, by stacking materials with different temperature resistivity into a double-layer thin-film structure and adjusting the thickness ratio of the double-layer thin film, can make the temperature resistivity of the double-layer thin film approach zero. The thermally stable thin-film resistor of the present invention can maintain a stable and reliable resistance value in environments with large temperature changes, and has the effect of improving the quality and thermal stability of electronic components.

[0010] The thickness of the resistive layer is 30 nm to 210 nm, and the thickness of the functional layer is 30 nm to 210 nm. Thus, the thickness ratio between the resistive layer and the functional layer can be adjusted, effectively controlling the temperature resistivity of the thin film to approach zero.

[0011] The resistive layer is made of a nickel-chromium-based alloy with an atomic percentage of 80% nickel and 20% chromium. The functional layer is made of vanadium nitride, and the thickness ratio of the resistive layer to the functional layer is between 2:3 and 3:2. Thus, the bilayer thin-film structure of the nickel-chromium-based alloy and vanadium nitride can achieve the lowest temperature resistivity at a specific thickness ratio, thereby improving the thermal stability of the resistor.

[0012] The thermally stable thin-film resistor of the present invention further comprises two electrodes, which are respectively located at both ends of the stacked structure of the resistive layer and the functional layer, and each electrode is electrically connected to both the resistive layer and the functional layer. Thus, when the two electrodes are electrically connected to a voltage source, current can be transmitted through the resistive layer and the functional layer, thereby achieving the effect of forming a double-layer thin-film resistor structure and generating resistive characteristics. Simple Explanation of the Diagram

[0013] [Figure 1] A side cross-sectional view of a preferred embodiment of the present invention. [Figure 2] A graph showing the relationship between the thickness ratio of the double-layer structure and the temperature resistivity in a preferred embodiment of the present invention. Implementation

[0014] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments of the present invention are described below in detail with reference to the accompanying drawings.

[0015] Please refer to Figure 1, which is a preferred embodiment of the thermally stable thin-film resistor of the present invention. It includes a substrate 1, a resistive layer 2 and a functional layer 3. The resistive layer 2 is located on the substrate 1 and the functional layer 3 is located on the resistive layer 2.

[0016] The substrate 1 is used to carry various electronic components and circuits. The material of the resistive element can be formed on the substrate 1 by sputtering, such as DC magnetron sputtering and radio-frequency magnetron sputtering, or by evaporation, laser deposition and other techniques. The substrate 1 can be made of ceramic materials such as alumina or silicon carbide.

[0017] The resistive layer 2 is formed as a thin film and stacked on one of the bearing surfaces of the substrate 1. The thickness of the resistive layer 2 can be 30 nm to 210 nm, preferably 40 nm, 60 nm, 70 nm, 80 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm or 200 nm. The temperature resistivity of the material of the resistive layer 2 is positive. The material of the resistive layer 2 can be an alloy, also known as an intermetallic compound, which is a compound formed by two or more metal elements in a fixed proportion. In this embodiment, the material of the resistive layer 2 is a nickel-chromium based alloy Ni 80Cr 20, that is, the atomic percentages of nickel and chromium are 80% and 20%, respectively. However, the material of the resistive layer 2 of the present invention can also be other atomic proportions or contain other elements, such as: 50% nickel and 50% chromium, nickel-chromium-silicon compound, nickel-chromium-silicon-aluminum compound, etc. The present invention is not limited to the above materials.

[0018] The functional layer 3 is stacked on the other surface of the resistive layer 2 on the side opposite to the substrate 1. The thickness of the functional layer 3 can be 30 nm to 210 nm, preferably 40 nm, 60 nm, 70 nm, 80 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm or 200 nm. The temperature resistivity of the material of the functional layer 3 is negative. In this embodiment, the material of the functional layer 3 is vanadium nitride (VN), which has high strength, corrosion resistance, thermal stability and electrical and thermal conductivity. By combining the functional layer 3 and the resistive layer 2, the thin film resistor structure can be protected and the thin film resistor characteristics can be changed.

[0019] Furthermore, the difference between the absolute value of the temperature resistivity of the material of the resistive layer 2 and the absolute value of the temperature resistivity of the material of the functional layer 3 is less than or equal to 500 ppm / ℃, and the thickness ratio of the resistive layer 2 to the functional layer 3 is between 1:7 and 7:1, which makes the temperature resistivity of the thin film resistor formed by the combination of the resistive layer 2 and the functional layer 3 approach zero.

[0020] Please refer again to Figure 2 and Table 1 below. In this embodiment, the material of the resistive layer 2 is a nickel-chromium-based alloy Ni 80Cr 20, and its temperature resistivity is 100±20 ppm / ℃; while the material of the functional layer 3 is vanadium nitride, and its temperature resistivity is -500±50 ppm / ℃. Furthermore, the thickness ratio of the resistive layer 2 to the functional layer 3 can be 2:5, 1:2, 2:3, 1:1, 3:2, 2:1, or 5:2, and preferably 1:1, which allows the temperature resistivity of the thin-film resistor to be as low as 15.2 ppm / ℃.

[0021] Table 1. Thin-film resistivity characteristics of nickel-chromium based alloy Ni 80Cr 20 combined with vanadium nitride Thickness (Ni 80Cr 20) Thickness (VN) Thickness ratio Temperature resistivity 60 nanometers 150 nanometers 2:5 -50±40 ppm / ℃ 70 nanometers 140 nanometers 1:2 -55±5 ppm / ℃ 80 nanometers 120 nanometers 2:3 -75±5 ppm / ℃ 100 nanometers 100 nanometers 1:1 15±5 ppm / ℃ 120 nanometers 80 nanometers 3:2 60±5 ppm / ℃ 140 nanometers 70 nanometers 2:1 140±5 ppm / ℃ 150 nanometers 60 nanometers 5:2 140±5 ppm / ℃

[0022] The thermally stable thin-film resistor of the present invention may also have two electrodes E, which are respectively located at both ends of the stacked structure of the resistive layer 2 and the functional layer 3, so that each electrode E is electrically connected to the resistive layer 2 and the functional layer 3 at the same time. When the two electrodes E are electrically connected to a voltage source V, current can be transmitted between the two electrodes E through the double-layer thin-film resistor structure formed by the resistive layer 2 and the functional layer 3.

[0023] In summary, the thermally stable thin-film resistor of the present invention, by stacking materials with different temperature resistivity into a double-layer thin-film structure and adjusting the thickness ratio of the double-layer thin film, can make the temperature resistivity of the double-layer thin film approach zero. The thermally stable thin-film resistor of the present invention can maintain a stable and reliable resistance value in environments with large temperature changes, thus improving the quality and thermal stability of electronic components.

[0024] Although the present invention has been disclosed using the above preferred embodiments, it is not intended to limit the present invention. Any modifications and alterations made by those skilled in the art to the above embodiments without departing from the spirit and scope of the present invention shall still fall within the scope of the technology protected by the present invention. Therefore, the scope of protection of the present invention shall include all changes within the meaning and equivalent scope of the appended claims.

[0025] 1:Substrate 2: Resistive layer 3: Functional layer E: Electrode V: Voltage source

Claims

1. A thermally stable thin-film resistor, comprising: a substrate; a resistive layer stacked on the substrate, wherein the resistive layer is made of a material with a positive temperature resistivity; and a functional layer stacked on another surface of the resistive layer opposite to the substrate, wherein the functional layer is made of a material with a negative temperature resistivity, wherein the difference between the absolute value of the temperature resistivity of the resistive layer and the absolute value of the temperature resistivity of the functional layer is less than or equal to 500 ppm / ℃, and the thickness ratio of the resistive layer to the functional layer is between 1:7 and 7:

1.

2. The thermally stable thin-film resistor as requested in item 1, wherein, The thickness of the resistive layer is 30 nanometers to 210 nanometers, and the thickness of the functional layer is 30 nanometers to 210 nanometers.

3. The thermally stable thin-film resistor as requested in item 1, wherein, The resistive layer is made of a nickel-chromium-based alloy with an atomic percentage of 80% nickel and 20% chromium. The functional layer is made of vanadium nitride. The thickness ratio of the resistive layer to the functional layer is between 2:3 and 3:

2.

4. The thermally stable thin-film resistor of claim 1 further comprises two electrodes, which are respectively located at both ends of the stacked structure of the resistive layer and the functional layer, and each electrode is electrically connected to the resistive layer and the functional layer simultaneously.

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