Sensing device
By setting a chromium oxide layer on the electrodes of the QCM sensor, the impact of temperature changes on detection accuracy was resolved, enabling high-precision gas detection under different temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TXC CORP
- Filing Date
- 2025-03-25
- Publication Date
- 2026-04-21
AI Technical Summary
The accuracy of QCM sensors is easily affected by temperature, leading to increased errors in high-temperature or drastic temperature environments, which affects detection sensitivity and versatility.
A chromium oxide layer is deposited on the electrode of a quartz substrate, with its thickness controlled between 1 nanometer and 10 nanometers, to prevent the diffusion of chromium metal atoms, reduce noise caused by electrode stress changes, and improve frequency stability.
It effectively reduces the frequency error of QCM sensors caused by temperature, improves detection accuracy and versatility, and ensures stable detection under different temperature environments.
Smart Images
Figure CN224152415U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an electronic device, and more particularly to a sensing device. Background Technology
[0002] With the development of technology, higher demands are being placed on gas detection technology in fields such as environmental monitoring, food safety, and medical testing. Gas, as a representative substance, can be used in various detection environments. Currently, gas detection technologies are mostly based on laboratory instrumental analysis methods, such as gas chromatography and ion mass spectrometry. These detection technologies suffer from problems such as expensive equipment, complex operation procedures, and the inability to perform gas detection in real time. However, QCM sensing systems based on quartz crystal microbalance (QCM) sensors can achieve high-speed detection of samples at room temperature with extremely high detection accuracy. QCM sensors are sensitive to changes in mass, utilizing the minute mass changes caused by odor molecules adsorbed on the electrode surface to convert them into frequency changes to reflect sample information.
[0003] However, the accuracy of QCM sensors is easily affected by temperature, which increases the error of QCM sensors in high-temperature or drastic temperature environments, affecting the detection sensitivity and versatility of QCM sensors. Utility Model Content
[0004] This invention provides a sensing device that can reduce the error caused by temperature, ensuring the sensitivity and versatility of the sensing device.
[0005] One embodiment of this utility model provides a sensing device, including a quartz substrate, a first electrode, and a second electrode. The first electrode and the second electrode are respectively disposed on a first surface and a second surface opposite to each other on the quartz substrate. The first electrode includes a first gold metal layer, a first chromium metal layer, and a first chromium oxide layer. The first gold metal layer is disposed on the first surface of the quartz substrate. The first chromium metal layer is disposed between the first gold metal layer and the quartz substrate. The first chromium oxide layer is disposed between the first chromium metal layer and the first gold metal layer. The thickness of the first chromium oxide layer is greater than or equal to 1 nanometer and less than or equal to 10 nanometers.
[0006] In one embodiment of this invention, the second electrode further includes a second gold metal layer, a second chromium metal layer, and a second chromium oxide layer. The second gold metal layer is disposed on the second surface of the quartz substrate. The second chromium metal layer is disposed between the second gold metal layer and the quartz substrate. The second chromium oxide layer is disposed between the second chromium metal layer and the second gold metal layer.
[0007] In one embodiment of this utility model, the thickness of the second chromium oxide layer is greater than or equal to 1 nanometer and less than or equal to 10 nanometers.
[0008] In one embodiment of the present invention, the sensing device further includes a first adsorption layer disposed on the first electrode.
[0009] In one embodiment of this invention, a second adsorption layer is further included, disposed on the second electrode.
[0010] In one embodiment of this utility model, an AC power supply is also included, which is electrically connected to the first electrode and the second electrode.
[0011] In one embodiment of this invention, the material of the first adsorption layer includes a nanofiber film.
[0012] In one embodiment of the present invention, the first adsorption layer comprises a gel material.
[0013] Based on the above, one electrode of the novel sensing device comprises a gold metal layer and a chromium metal layer, with a chromium oxide layer disposed between the gold and chromium metal layers. Since the stress on the electrode and the quartz substrate is affected by temperature changes, it is one of the sources of measurement error in the sensing device. This stress originates from chromium present in the electrode substrate layer, which diffuses to the gold metal layer during high-temperature processing, causing the electrode to become a chromium-gold-chromium dual heterogeneous interface. An appropriately thick chromium oxide layer can prevent chromium atoms from diffusing into the gold metal layer during processing, thereby reducing the stress on the sensing device and further reducing the noise generated by stress. Furthermore, by controlling the thickness of the chromium oxide layer, the accuracy of the sensing device can be maintained, effectively reducing the error of the sensing device and improving its versatility.
[0014] To make the above-mentioned features and advantages of this utility model more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description
[0015] Figure 1A This is a schematic diagram of the sensing device according to the present invention. Figure 1B yes Figure 1A A schematic diagram of the oscillation waveform of the sensing device. Figure 1C yes Figure 1A A schematic diagram of the sensing device adsorbing particles in the embodiment. Figure 1D yes Figure 1C A schematic diagram of the oscillation waveform of the sensing device;
[0016] Figure 2 This is a QCM detector, and the graph shows the relationship between temperature and frequency deviation.
[0017] Figure 3 This is a partial structural schematic diagram of a sensing device according to an embodiment of the present invention. Detailed Implementation
[0018] The foregoing description and other technical contents, features, and effects of this invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention.
[0019] Figure 1A This is a schematic diagram of the structure of a sensing device according to an embodiment of the present invention. Figure 1B yes Figure 1A A schematic diagram of the oscillation waveform of the sensing device. Please refer to... Figure 1A as well as Figure 1B The sensing device 1 includes a quartz substrate 100, a first electrode 10A, and a second electrode 10B. The quartz substrate 100 has a first surface 101 and a second surface 102 disposed opposite to each other. The first electrode 10A and the second electrode 10B can be disposed on the first surface 101 and the second surface 102, respectively. The outlines of the first electrode 10A and the second electrode 10B on the projection plane of the quartz substrate 100 (e.g., projection in the Z direction) can be square, circular, or have other shapes, and this invention is not limited thereto. The sensing device 1 can be used for gas or liquid composition analysis and minute mass measurement, and therefore can be applied to different detection systems, such as in the fields of chemical detection, electronics, physics, biology, medicine, and surface science, and this invention is not limited thereto.
[0020] In detail, the sensing device 1 includes a Quartz Crystal Microbalance (QCM) sensor. The QCM sensor operates on the principle of the inverse piezoelectric effect of quartz crystals. When an alternating electric field is applied to the two electrodes of the quartz crystal, the crystal will vibrate mechanically. When the oscillation frequency of the quartz crystal is close to or substantially the same as the oscillation frequency of the alternating electric field, the amplitude of the quartz crystal reaches its maximum, exhibiting a stable resonance phenomenon. Utilizing this characteristic, the resonance frequency can be measured by electrically connecting the quartz crystal to a circuit. For example, in… Figure 1A In this process, the sensing device 1 may include an AC power supply 20, electrically connected to a first electrode 10A and a second electrode 10B. When the AC power supply 20 is enabled, the sensing device 1 can generate a first waveform W1 with a first frequency f1, such as... Figure 1B As shown.
[0021] Please refer to the following: Figure 1C When sensing device 1 adsorbs a analyte, such as particle P, the total mass of sensing device 1 changes, and therefore the resonant frequency of sensing device 1 also changes. Figure 1DFor example, when the AC power supply 20 powers the sensing device 1 that adsorbs particles P, the sensing device 1 can generate a second waveform W2 with a second frequency f2. By analyzing the changes in the first frequency f1 and the second frequency f2, the total mass of particles P adsorbed by the sensing device 1 can be measured, and the concentration value of particles P in the environment can be deduced to achieve the purpose of concentration detection.
[0022] Figure 2 This is a QCM detector, and the graph shows the relationship between temperature and frequency deviation. QCM sensors require a constant temperature environment during measurement because the material properties of the quartz crystal cause its vibration frequency to change with temperature, and the stress on the electrodes also changes with temperature. Both the quartz crystal and the electrodes affect the frequency measured by the QCM sensor, leading to measurement errors. Figure 2 For example, at a temperature of 15 degrees Celsius, the frequency deviation of a QCM sensor is approximately 5 ppm, while at a temperature of 50 degrees Celsius, the frequency deviation becomes approximately -15 ppm. Therefore, reducing the impact of temperature on the frequency error of a QCM sensor is an important issue in QCM sensor technology.
[0023] Figure 3 This is a partial structural schematic diagram of a sensing device according to an embodiment of the present invention. Please refer to... Figure 3 The first electrode 10A may include a first gold metal layer 110A, a first chromium metal layer 120A, and a first chromium oxide layer 130A. The first gold metal layer 110A is disposed on the first surface 101. The first chromium metal layer 120A is disposed between the first gold metal layer 110A and the quartz substrate 100. In some embodiments, the first chromium metal layer 120A may directly contact the first surface 101. The first chromium oxide layer 130A is disposed between the first chromium metal layer 120A and the first gold metal layer 110A. Alternatively, the first chromium metal layer 120A, the first chromium oxide layer 130A, and the first gold metal layer 110A of the first electrode 10A may be sequentially stacked from the first surface 101 in the Z direction.
[0024] The preparation methods of the first chromium metal layer 120A, the first chromium oxide layer 130A and the first gold metal layer 110A can be formed by sequentially depositing them on the first surface 101 using physical vapor deposition (PVD), chemical vapor deposition (CVD) or atomic layer deposition (ALD), but the present invention is not limited thereto.
[0025] In the sensing device 1, the frequency change of the sensing chip, which consists of a quartz substrate 100, a first electrode 10A, and a second electrode 10B, can satisfy the following conditional equation:
[0026]
[0027] Where Δf is the frequency change sensed by sensing device 1; A is the surface area of the thin film on the first electrode 10A used for adsorbing substances; ρ is the density of quartz substrate 100; μ is the shear modulus of quartz substrate 100 (g / (cm*s2)); Δm is the mass of the adsorbed substance; f0 is the fundamental frequency of the sensing chip; fA is the frequency noise caused by stress; and fB is the frequency noise caused by temperature on quartz substrate 100. Both fA and fB are functions of temperature and are the noise sources of the frequency change sensed by sensing device 1. fB can be compensated for using empirical formulas for temperature compensation. However, fA is affected by stress, is unpredictable, and difficult to correct.
[0028] As mentioned above, the sensing accuracy of sensing device 1 is proportional to the square of the fundamental frequency f0 of the sensing chip. However, a higher frequency requires a corresponding reduction in the thickness of the sensing chip. Conversely, a thinner sensing chip is more susceptible to stress variations in the electrodes. Therefore, in this novel design, the first electrode 10A is positioned between the first gold metal layer 110A and the first chromium metal layer 120A via a first chromium oxide layer 130A (e.g., chromium monoxide CrO). The stress on the first electrode 10A and the quartz substrate 100 is affected by temperature changes, contributing to the aforementioned function fA. This stress originates from the diffusion of atoms from the first chromium metal layer 120A to the first gold metal layer 110A during high-temperature processing, resulting in a chromium-gold-chromium dual heterogeneous interface on the first electrode 10A. The presence of the first chromium oxide layer 130A prevents the diffusion of atoms from the first chromium metal layer 120A to the first gold metal layer 110A during processing, effectively reducing the stress on the sensing device 1 and further minimizing stress-induced noise.
[0029] Furthermore, by controlling the thickness d1 of the first chromium oxide layer 130A to be greater than or equal to 1 nanometer and less than or equal to 10 nanometers, the influence of temperature changes on stress is reduced, the accuracy of the sensing device 1 is improved, and the thickness of the first electrode 10A is not too large, so as to maintain the sensitivity of the sensing device 1.
[0030] On the other hand, in this embodiment, the second electrode 10B may also include a second gold metal layer 110B, a second chromium metal layer 120B, and a second chromium oxide layer 130B. The second gold metal layer 110B is disposed on the second surface 102. The second chromium metal layer 120B is disposed between the second gold metal layer 110B and the quartz substrate 100. In some embodiments, the second chromium metal layer 120B may directly contact the second surface 102. The second chromium oxide layer 130B is disposed between the second chromium metal layer 120B and the second gold metal layer 110B. The preparation methods of the second gold metal layer 110B, the second chromium metal layer 120B, and the second chromium oxide layer 130B can refer to the aforementioned preparation methods of the first gold metal layer 110A, the first chromium metal layer 120A, and the first chromium oxide layer 130A, and will not be repeated here. In other words, the second electrode 10B and the first electrode 10A may be mirror images of the quartz substrate 100; however, this invention is not limited to this. In other embodiments, the second electrode 10B of the sensing device may be a stacked structure of a second gold metal layer 110B and a second chromium metal layer 120B, or a stacked structure of other metals or alloys. In some embodiments, the thickness d2 of the second chromium oxide layer 130B may also be greater than or equal to 1 nanometer and less than or equal to 10 nanometers.
[0031] In addition, in order to adsorb particles of the sensing material (e.g.) Figure 1C In the case of particles P), the sensing device 1 may further include a corresponding adsorption layer. For example, the sensing device 1 may have a first adsorption layer 140A disposed on the surface of the first electrode 10A away from the quartz substrate 100. Similarly, the sensing device 1 may have a second adsorption layer 140B disposed on the surface of the second electrode 10B away from the quartz substrate 100. The materials of the first adsorption layer 140A and the second adsorption layer 140B may include nanofiber films or gel materials, but the present invention is not limited thereto. In other embodiments, the sensing device may also have only one of the first adsorption layer 140A or the second adsorption layer 140B (i.e., single-sided detection), and the present invention is not limited thereto.
[0032] In summary, the electrode of the novel sensing device comprises a gold metal layer and a chromium metal layer, with a chromium oxide layer disposed between the gold and chromium metal layers. Since the stress on the electrode and the quartz substrate is affected by temperature changes, it is one of the sources of measurement error in the sensing device. This stress originates from chromium present in the electrode substrate layer, which diffuses to the gold metal layer during high-temperature processing, causing the electrode to become a chromium-gold-chromium dual heterogeneous interface. An appropriately thick chromium oxide layer can prevent chromium atoms from diffusing into the gold metal layer during processing, thereby reducing the stress on the sensing device and further reducing the noise generated by stress. Furthermore, by controlling the thickness of the chromium oxide layer, the accuracy of the sensing device can be maintained, effectively reducing the error of the sensing device and improving its versatility.
[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A sensing device, characterized by include: A quartz substrate having a first surface and a second surface opposite to each other; as well as A first electrode and a second electrode are respectively disposed on the first surface and the second surface, wherein the first electrode includes: A first gold metal layer is disposed on the first surface of the quartz substrate; A first chromium metal layer is disposed between the first gold metal layer and the quartz substrate; and A first chromium oxide layer is disposed between the first chromium metal layer and the first gold metal layer, wherein the thickness of the first chromium oxide layer is greater than or equal to 1 nanometer and less than or equal to 10 nanometers.
2. The sensing device of claim 1, wherein, The second electrode also includes: A second gold metal layer is disposed on the second surface of the quartz substrate; A second chromium metal layer is disposed between the second gold metal layer and the quartz substrate; and A second chromium oxide layer is disposed between the second chromium metal layer and the second gold metal layer.
3. The sensing device of claim 2, wherein, The thickness of the second chromium oxide layer is greater than or equal to 1 nanometer and less than or equal to 10 nanometers.
4. The sensing device of claim 1, wherein, It also includes a first adsorption layer disposed on the first electrode.
5. The sensing device of claim 4, wherein, It also includes a second adsorption layer disposed on the second electrode.
6. The sensing device of claim 4, wherein, The material of the first adsorption layer includes a nanofiber film.
7. The sensing device of claim 4, wherein, The first adsorption layer comprises a gel material.