Sputtering thin film system structure for ultralow-temperature environment force sensor and deposition method

Abstract

The invention discloses a sputtering film system structure for an ultralow-temperature environment force sensor, and belongs to the technical field of sensors. The sputtering film system structure comprises a substrate, a substrate layer, a spacing layer I, a polytetrafluoroethylene layer, a spacing layer II, a semiconductor layer and an insulating protection layer which are sequentially stacked, and the spacing layer I and the spacing layer II are zinc sulfide film layers. According to the invention, the material has excellent performance and long-term stability at-180 DEG C or even lower temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a sputtering thin film system structure and a deposition method for a force sensor in an ultra-low temperature environment. Background Art

[0002] Thin film force sensor is a device that converts mechanical quantity into electrical signal. The existing thin film force sensor film structure includes core, substrate, spacer layer, semiconductor layer and insulating protective layer. The core is generally made of stainless steel, the substrate is made of Ti, the spacer layer is made of SiO2, and the semiconductor film layer is made of silicon carbide. Thin film force sensors have been widely used in aerospace, machinery manufacturing, civil engineering and mining and other related fields due to their high precision, good creep resistance, strong anti-interference ability and other properties.

[0003] However, the existing membrane structure is extremely unstable at ultra-low temperatures (below -50°C), making it difficult to apply to force sensors that need to withstand ultra-low temperature environments for a long time. In ultra-low temperature environments (below -50°C), the zero-point output of existing sensors is unstable and prone to zero drift, and the output linearity of the sensor core is poor. Currently, there is no mature and feasible membrane design solution that can withstand ultra-low temperature environments. In addition, the adhesion between the existing sensor spacer layer SiO2 and the substrate layer and the insulating layer is insufficient, and the stability of the membrane structure cannot be guaranteed. Summary of the invention

[0004] In view of this, the present invention provides a sputtering thin film film system structure and deposition method for an ultra-low temperature environment force sensor, which can have excellent performance and long-term stability at temperatures of -180°C or even lower.

[0005] The present invention is achieved through the following technical solutions:

[0006] A sputtered thin film film system structure for an ultra-low temperature environment force sensor, comprising: a substrate, a substrate layer, a spacer layer I, a polytetrafluoroethylene layer, a spacer layer II, a semiconductor layer and an insulating protective layer stacked in sequence;

[0007] Both the spacer layer I and the spacer layer II are zinc sulfide film layers.

[0008] Furthermore, the thickness of the spacer layer I and the spacer layer II are both 15 nm±0.5 nm.

[0009] Furthermore, the thickness of the polytetrafluoroethylene layer is not greater than 60 nm.

[0010] Furthermore, the material of the semiconductor layer is gallium nitride, and the thickness of the semiconductor layer is no more than 50 nm.

[0011] Furthermore, the material of the insulating protection layer is silicon dioxide.

[0012] Furthermore, the material of the substrate is titanium alloy, and the material of the substrate layer is germanium.

[0013] Furthermore, the thickness of the titanium alloy is 100 μm to 200 μm, and the thickness of the germanium is 20 nm±2 nm.

[0014] Furthermore, the titanium alloy is TC4.

[0015] A sputtering thin film film system structure deposition method suitable for ultra-low temperature environment force sensor, the method is:

[0016] Step 1: Depositing a substrate layer of germanium on the surface of the titanium alloy substrate using a plasma-assisted electron beam evaporation deposition method;

[0017] Step 2: using PECVD technology to deposit a spacer layer I of zinc sulfide on the surface of germanium;

[0018] Step 3, depositing a polytetrafluoroethylene layer on the spacer layer I by using a low-power electron beam evaporation deposition method;

[0019] Step 4: using PECVD technology to deposit spacer layer II zinc sulfide on the surface of the polytetrafluoroethylene layer;

[0020] Step 5: using ECR plasma enhanced metal organic chemical vapor epitaxy (ECR-MOPECVD) technology to deposit a semiconductor layer of gallium nitride on the surface of the spacer layer II;

[0021] Step 6: Use PECVD technology to deposit an insulating protective layer of silicon dioxide on the semiconductor layer.

[0022] Beneficial effects:

[0023] (1) The present invention provides a sputtered thin film membrane structure for an ultra-low temperature environment force sensor, which is provided with a polytetrafluoroethylene layer. Polytetrafluoroethylene [(C2F4)n] has excellent cold resistance and will not cause performance degradation due to temperature changes. It is also effective for heat insulation and insulation. The use of polytetrafluoroethylene in an ultra-low temperature environment force sensor can ensure that the sensor can be used for a long time in an ultra-low temperature environment of -180°C to -260°C. At the same time, it is acid and alkali resistant and has extremely high low temperature resistance and working reliability. In addition, the present invention also uses a zinc sulfide film layer as a spacer layer, that is, zinc sulfide is used to achieve the bonding between layers. Zinc sulfide is well bonded to each functional membrane layer material, the structure is stable and has strong environmental tolerance, and can play a good role in improving the stability of the membrane structure. The polytetrafluoroethylene layer is tightly arranged in the membrane structure to further ensure the tolerance of the membrane structure under ultra-low temperature operation.

[0024] (2) The thickness of the spacer layer I and the spacer layer II of the present invention are both 15 nm ± 0.5 nm, which effectively reduces the film thickness while improving the bonding strength between the layers.

[0025] (3) The material of the semiconductor layer of the present invention is gallium nitride. Compared with the semiconductor film layers selected in other existing film system solutions, the gallium nitride (GaN) film layer has the advantages of wide band gap, strong atomic bond, high thermal conductivity, and good chemical stability. It is almost not corroded by any acidic substances. At the same time, it has the strong radiation resistance urgently needed by aerospace products, and can greatly improve the comprehensive performance of the thin film system.

[0026] (4) The material of the substrate of the present invention is titanium alloy, and the material of the substrate layer is germanium. The titanium alloy and germanium are easy to adhere to each other and are tightly combined, which can greatly improve the stability of the film structure.

[0027] (5) The titanium alloy of the present invention is TC4, which has higher strength and lighter weight, and can still guarantee mechanical properties in a low temperature environment of -180°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the sputtered thin film system of the present invention.

[0029] Among them, 1-substrate, 2-substrate layer, 3-spacer layer I, 4-polytetrafluoroethylene layer, 5-spacer layer II, 6-semiconductor layer, 7-insulating protection layer. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0031] Embodiment 1:

[0032] This embodiment provides a sputtered thin film film system structure for an ultra-low temperature environment force sensor, see the attached Figure 1 , comprising a substrate 1, a substrate layer 2, a spacer layer I 3, a polytetrafluoroethylene layer 4, a spacer layer II 5, a semiconductor layer 6 and an insulating protection layer 7 which are stacked in sequence;

[0033] The spacer layer Ⅰ3 and the spacer layer Ⅱ5 are both zinc sulfide (ZnS) film layers.

[0034] The present embodiment provides a sputtered thin film membrane structure for an ultra-low temperature environment force sensor, which is provided with a polytetrafluoroethylene layer 4. Polytetrafluoroethylene [(C2F4)n] has excellent cold resistance and will not cause performance degradation due to temperature changes. It is also effective when used for heat insulation and insulation. The use of polytetrafluoroethylene in ultra-low temperature environment force sensors can ensure that the sensor can be used for a long time in an ultra-low temperature environment of -180°C to -260°C. At the same time, it is acid and alkali resistant, and has extremely high low temperature resistance and working reliability. In addition, in the present embodiment, a zinc sulfide film layer is also used as a spacer layer, that is, zinc sulfide is used to achieve the bonding between layers. Zinc sulfide is well bonded with each functional membrane layer material, the structure is stable and has strong environmental tolerance, and can play a good role in improving the stability of the membrane structure. The polytetrafluoroethylene layer 4 is tightly arranged in the membrane structure to further ensure the reliability of the membrane structure under ultra-low temperature operation.

[0035] In one embodiment, the thickness of the spacer layer I3 and the spacer layer II5 are respectively 15nm±0.5nm, which effectively reduces the thickness of the film layer while improving the bonding strength between the layers, thereby reducing the stress between the film layers and preventing film peeling (the film thickness of the spacer layer in the prior art is about 100μm).

[0036] In one embodiment, the thickness of the polytetrafluoroethylene layer 4 is no greater than 60 nm;

[0037] In one embodiment, the material of the substrate 1 is titanium alloy (TC4) with a thickness of 100 μm to 200 μm; the material of the substrate layer 2 is germanium (Ge) with a thickness of 20 nm ± 2 nm. Titanium alloy TC4 has higher strength and lighter weight, and can still guarantee mechanical properties in an environment of -180°C; titanium alloy and germanium are easy to adhere and tightly combined, which can greatly improve the stability of the film structure.

[0038] In one embodiment, the material of the semiconductor layer 6 is gallium nitride (GaN), and the thickness of the semiconductor layer 6 is not greater than 50nm; the material of the insulating protection layer 7 is silicon dioxide (SiO2). Compared with the semiconductor film layers selected by other existing film system solutions, the gallium nitride (GaN) film layer has the advantages of wide band gap, strong atomic bond, high thermal conductivity, and good chemical stability. It is almost not corroded by any acidic substances. At the same time, it has the strong radiation resistance urgently needed by aerospace products, which can greatly improve the comprehensive performance of the thin film system.

[0039] Embodiment 2:

[0040] This embodiment provides a method for depositing a sputtered thin film structure for a force sensor in an ultra-low temperature environment. Based on the sputtered thin film structure for a force sensor in an ultra-low temperature environment described in Embodiment 1, the method is as follows:

[0041] Step 1: Depositing a substrate layer 2 of germanium on the surface of a titanium alloy substrate 1 by a plasma-assisted electron beam evaporation deposition method;

[0042] Step 2: using PECVD technology to deposit a spacer layer of zinc sulfide on the surface of germanium;

[0043] Step 3: depositing a polytetrafluoroethylene layer 4 on the spacer layer I 3 by using a low-power electron beam evaporation deposition method;

[0044] Step 4: using PECVD technology to deposit a spacer layer II 5 of zinc sulfide on the surface of the polytetrafluoroethylene layer 4;

[0045] Step 5: using ECR plasma enhanced metal organic chemical vapor epitaxy (ECR-MOPECVD) technology to deposit the semiconductor layer 6 gallium nitride on the surface of the spacer layer II 5;

[0046] Step 6: Deposit an insulating protective layer 7 of silicon dioxide on the semiconductor layer 6 using PECVD technology.

[0047] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A sputtered thin film structure for a force sensor in an ultra-low temperature environment, characterized in that: include: A substrate, a substrate layer, a spacer layer I, a polytetrafluoroethylene layer, a spacer layer II, a semiconductor layer and an insulating protective layer stacked in sequence; Both the spacer layer I and the spacer layer II are zinc sulfide film layers.

2. A sputtered thin film structure for a force sensor in an ultra-low temperature environment as claimed in claim 1, characterized in that: The thickness of the spacer layer I and the spacer layer II are both 15nm±0.5nm.

3. A sputtered thin film structure for a force sensor in an ultra-low temperature environment as claimed in claim 1, characterized in that: The thickness of the polytetrafluoroethylene layer is not more than 60 nm.

4. A sputtered thin film structure for a force sensor in an ultra-low temperature environment as claimed in claim 1, characterized in that: The material of the semiconductor layer is gallium nitride, and the thickness of the semiconductor layer is no more than 50 nm.

5. A sputtered thin film system structure for a force sensor in an ultra-low temperature environment as claimed in claim 1, characterized in that: The material of the insulating protection layer is silicon dioxide.

6. A sputtered thin film structure for a force sensor in an ultra-low temperature environment as claimed in any one of claims 1 to 5, characterized in that: The material of the base is titanium alloy, and the material of the substrate layer is germanium.

7. A sputtered thin film structure for a force sensor in an ultra-low temperature environment as claimed in claim 6, characterized in that: The thickness of the titanium alloy is 100 μm to 200 μm, and the thickness of the germanium is 20 nm ± 2 nm.

8. A sputtered thin film system structure for a force sensor in an ultra-low temperature environment as claimed in claim 6, characterized in that: The titanium alloy is TC4.

9. A sputtering thin film film structure deposition method suitable for ultra-low temperature environment force sensor, characterized in that: The method is: Step 1: Depositing a substrate layer of germanium on the surface of the titanium alloy substrate using a plasma-assisted electron beam evaporation deposition method; Step 2: using PECVD technology to deposit a spacer layer I of zinc sulfide on the surface of germanium; Step 3, depositing a polytetrafluoroethylene layer on the spacer layer I by using a low-power electron beam evaporation deposition method; Step 4: using PECVD technology to deposit spacer layer II zinc sulfide on the surface of the polytetrafluoroethylene layer; Step 5: using ECR plasma enhanced metal organic chemical vapor epitaxy (ECR-MOPECVD) technology to deposit a semiconductor layer of gallium nitride on the surface of the spacer layer II; Step 6: Use PECVD technology to deposit an insulating protective layer of silicon dioxide on the semiconductor layer.

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