Method for inhibiting local electrification of surface layer of dielectric material

Abstract

The invention provides a method for inhibiting local electrification of a surface layer of a dielectric material, which comprises the following steps of: introducing a layer of semiconductor material film with nanoscale thickness on the surface of the dielectric material; the semiconductor material film is prepared from one or more raw materials of the semiconductor material film; the raw material of the semiconductor material film is pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene; and the fullerene is C60 or C70. The method provided by the invention is low in cost, low in insertion loss while inhibiting local electrification of the surface layer of the dielectric material, and wide in application prospect in the technical field of dielectric material electrification protection.

Description

Technical Field

[0001] The invention belongs to the technical field of dielectric material electrification protection, relates to suppressing local electrification, and specifically relates to a method for suppressing local electrification on the surface of a dielectric material. Background Art

[0002] During the on-orbit operation of a spacecraft, the surface of the dielectric material will be locally charged or unequally charged under the action of space plasma, resulting in a potential difference at different positions of the same material and between materials, thus causing electrostatic discharge. A large number of high-energy electrons in the space environment pass through the shielding layer and are deposited on the surface of the dielectric material inside the spacecraft, which will also generate local charging and cause electrostatic discharge. Electrostatic discharge can seriously affect the safe and stable operation of spacecraft on orbit. In addition, the local surface charging of the dielectric window of a high-power microwave source caused by the secondary electron multiplication effect can also lead to surface discharge, thereby damaging the dielectric window.

[0003] At present, the method of preparing a conductive coating on the surface of the dielectric material is mainly used to suppress the local or unequal charging of the surface of the dielectric material. Commonly used conductive coatings include indium tin oxide (ITO), titanium nitride (TiN) and carburized polyimide film. Although these coatings have conductive properties and can discharge the charges deposited on the surface of the dielectric material, they have the disadvantage of excessive insertion loss when facing microwave application environments. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for suppressing local surface charging of a dielectric material, so as to solve the technical problem that the insertion loss of the dielectric material in the prior art needs to be further reduced when facing a microwave application environment during the process of suppressing local surface charging.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A method for suppressing localized charging of the surface layer of a dielectric material comprises the dielectric material and introduces a semiconductor material film with a nanometer thickness on the surface of the dielectric material.

[0007] The semiconductor material film is prepared from one or more semiconductor material film raw materials.

[0008] The raw material of the semiconductor material film is pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene.

[0009] The fullerene is C60 or C70.

[0010] The present invention also has the following technical features:

[0011] Preferably, the nanoscale thickness is 10 to 40 nm.

[0012] Preferably, the semiconductor material film is formed by evaporating one or more semiconductor material film raw materials in powder form onto the surface of the dielectric material using vacuum evaporation technology.

[0013] Specifically, the method comprises the following steps:

[0014] Step 1: Place the dielectric material into the vacuum evaporation system and evacuate the system.

[0015] Step 2: shield the dielectric material with a baffle, open the beam source baffles of one or more semiconductor material thin film raw materials at the same time, pass current through the beam source of one or more semiconductor material thin film raw materials at the same time, and heat the beam source.

[0016] Step three, opening the baffle that blocks the dielectric material, and evaporating a semiconductor material film on the surface of the dielectric material.

[0017] Step 4: After the evaporation is completed, the beam source current of one or more semiconductor material thin film raw materials is disconnected simultaneously, and after the temperature drops to room temperature, the dielectric material with the surface evaporated semiconductor material thin film is taken out to obtain the dielectric material with the surface evaporated semiconductor material thin film.

[0018] Preferably, in step 1, the pressure in the vacuum evaporation system is evacuated to be less than or equal to 4×10 -4 Pa.

[0019] Preferably, the purity of the raw materials of the semiconductor material film is greater than or equal to 95wt.%.

[0020] Preferably, the dielectric material is polyimide, polytetrafluoroethylene, alumina ceramic or glass.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (I) The method proposed in the present invention has low cost, and has low insertion loss while suppressing localized charging on the surface of dielectric materials, and has broad application prospects in the field of dielectric material charging protection technology.

[0023] (II) From the perspective of materials, the present invention introduces a nanometer-thick semiconductor material film on the surface of the dielectric material, utilizes the extremely weak conductive properties of the semiconductor material film to discharge the deposited charge, and suppresses the localized charge on the surface of the dielectric material.

[0024] (III) The present invention prepares a semiconductor material film on the surface of a dielectric material through vacuum evaporation technology, which effectively suppresses the localized charging of the surface layer of the dielectric material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the test result of the secondary electron current waveform of the alumina ceramic dielectric material under two consecutive pulse electron beam irradiations.

[0026] Figure 2 It is the test result of the secondary electron current waveform of alumina ceramic dielectric material / pentacene film (20nm) under two consecutive pulse electron beam irradiations.

[0027] Figure 3 It is the test result of the secondary electron current waveform of alumina ceramic dielectric material / fullerene film (15nm) under two consecutive pulsed electron beam irradiations.

[0028] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0029] It should be noted that all raw materials and instruments in the present invention, unless otherwise specified, are all raw materials and instruments known in the prior art. For example, pentacene uses known commercially available pentacene. Polyimide and polytetrafluoroethylene both use commercially available polyimide and polytetrafluoroethylene with conventional number average molecular weight. For example, a vacuum evaporation system uses a known vacuum evaporation system.

[0030] The room temperature in the present invention refers to the natural environment temperature during the production and processing process. Usually, the temperature is generally within the range of 20±10°C.

[0031] The raw materials of the semiconductor material film in the present invention, namely pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene, are respectively located in different beam sources.

[0032] The alumina ceramic dielectric material / pentacene film (20 nm) in the present invention refers to an alumina ceramic dielectric material with a 20 nm pentacene film evaporated on the surface.

[0033] The alumina ceramic dielectric material / fullerene film (15 nm) in the present invention refers to an alumina ceramic dielectric material with a 15 nm fullerene film evaporated on the surface.

[0034] The high beam current density in the present invention refers to a beam current density of 300 to 400 nA / mm 2 .

[0035] According to the method for suppressing localized charging of the surface layer of a dielectric material proposed by the present invention, the most economical and simple method is to prepare a thin film on the surface of the dielectric material using only one semiconductor material thin film raw material. The present invention is described in detail below in conjunction with specific embodiments.

[0036] In accordance with the above technical scheme, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of this application fall within the protection scope of the present invention.

[0037] Embodiment 1:

[0038] This embodiment provides a method for suppressing localized charging of the surface of a dielectric material. The method is to introduce a layer of pentacene film with a thickness of nanometer level on the surface of an alumina ceramic dielectric material with a size of 12 mm×12 mm×0.635 mm.

[0039] The thickness of the pentacene film was 20 nm.

[0040] The pentacene film is formed by evaporating powdered pentacene onto the surface of an alumina ceramic dielectric material using a vacuum evaporation technique.

[0041] The method specifically comprises the following steps:

[0042] Step 1: Place the alumina ceramic dielectric material into the vacuum evaporation system and evacuate the system until the pressure is less than or equal to 4×10 -4 Pa.

[0043] Step 2: shield the alumina ceramic dielectric material with a baffle, open the beam source baffle of pentacene, pass current through the beam source of pentacene, and heat the beam source.

[0044] Step three, opening the baffle shielding the alumina ceramic dielectric material, and vapor-depositing a pentacene film on the surface of the alumina ceramic dielectric material.

[0045] Step 4: After the evaporation is completed, the beam source current of pentacene is disconnected, and after the temperature drops to room temperature, the alumina ceramic dielectric material with the pentacene film evaporated on the surface is taken out, so as to obtain the alumina ceramic dielectric material with the pentacene film evaporated on the surface.

[0046] The purity of pentacene is greater than or equal to 95 wt.%.

[0047] A pulsed electron beam with high beam density is used to irradiate the sample twice in succession, and the surface charging condition of the sample is determined by measuring the changes in the secondary electron current waveform emitted by the sample.

[0048] First, a pulsed electron beam with a high beam current density of 3 keV and a pulse width of 15 μs was used to irradiate the alumina ceramic dielectric material twice. The secondary electron current waveform measured by the oscilloscope after amplification by the current amplifier is shown in the figure. Figure 1. When the alumina ceramic dielectric material is irradiated by the first pulse electron beam, a narrow pulse peak appears in the secondary electron current, which then rapidly decays to an equilibrium value. When irradiated by the second pulse electron beam, the narrow pulse peak of the secondary electron current disappears, presenting only a rectangular waveform. Since the alumina ceramic dielectric material has a high secondary electron emission coefficient and poor electrical conductivity, the surface of the irradiated area is positively charged after electron beam irradiation, causing the secondary electron current to rapidly decay to an equilibrium value (i.e., the secondary electron emission coefficient is equal to 1). Since the surface of the alumina ceramic dielectric material is locally charged, the waveform of the secondary electron current during the second irradiation of the pulse electron beam is rectangular, and the value is significantly smaller than that of the first irradiation.

[0049] Secondly, the same pulsed electron beam was used to irradiate the alumina ceramic dielectric material / pentacene film (20nm) twice in succession. The secondary electron current waveform was measured as shown in Figure 2 When the alumina ceramic dielectric material / pentacene film (20nm) was irradiated by the pulsed electron beam for the first time, the secondary electron current waveform was significantly different from that when the film without the evaporated film was irradiated by the electron beam for the first time, and the narrow pulse peak disappeared. In addition, the secondary electron current pulse waveform and amplitude during two consecutive irradiations were consistent, indicating that there was no localized charging on the surface of the alumina ceramic dielectric material / pentacene film (20nm).

[0050] The measurement results of the secondary electron current pulse waveform under two consecutive irradiations of a high beam density pulse electron beam show that the method for suppressing localized charging on the surface of a dielectric material proposed in the present invention can effectively suppress localized charging on the surface of a dielectric material.

[0051] Embodiment 2:

[0052] This embodiment provides a method for suppressing localized charging of the surface layer of a dielectric material. The method is basically the same as that of Embodiment 1, except that: the pentacene film is changed to a fullerene film; the thickness of the film is changed from 20 nm to 15 nm; and the purity of the film raw material is changed from greater than or equal to 95 wt.% to greater than or equal to 98 wt.%.

[0053] In this embodiment, the fullerene is C60, and C60 uses known C60.

[0054] Then, the alumina ceramic dielectric material / fullerene film (15 nm) was irradiated twice with the same pulse electron beam as in Example 1, and the secondary electron current waveform was measured as shown in FIG. Figure 3 The secondary electron currents obtained by two consecutive irradiations of the pulsed electron beam are all rectangular in shape and have the same amplitude. Compared with the alumina ceramic dielectric material, the narrow pulse peak disappears, which indicates that there is no local charging on the surface of the alumina ceramic dielectric material / fullerene film (15nm).

[0055] The measurement results of the secondary electron current pulse waveform under two consecutive irradiations of a high beam density pulse electron beam show that the method for suppressing localized charging on the surface of a dielectric material proposed in the present invention can effectively suppress localized charging on the surface of a dielectric material.

[0056] Semiconductor material films made of pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene do not have free carriers themselves. When charges are injected from the outside, the charges are transferred between different molecules in a jumping manner, showing extremely weak conductivity on a macro scale. Indium tin oxide or titanium nitride are semiconductor materials with good conductivity, but both of them have free carriers themselves. Therefore, when it comes to microwave applications, compared with conductive coatings made of indium tin oxide or titanium nitride, semiconductor material films made of pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene have less impact on insertion loss.

Claims

1. A method for suppressing localized charging of a surface layer of a dielectric material, the method comprising a dielectric material, characterized in that: The method is to introduce a nanometer-thick semiconductor material film on the surface of the dielectric material; The semiconductor material film is prepared from one or more semiconductor material film raw materials; The raw material of the semiconductor material film is pentacene, 8-hydroxyquinoline aluminum, copper phthalocyanine or fullerene.

2. The method for suppressing localized charging of the surface of a dielectric material according to claim 1, characterized in that: The nanometer-level thickness is 10 to 40 nm.

3. The method for suppressing localized charging of the surface of a dielectric material according to claim 1, characterized in that: The semiconductor material film is formed by evaporating one or more semiconductor material film raw materials in powder form onto the surface of a dielectric material using vacuum evaporation technology.

4. The method for suppressing localized charging of the surface of a dielectric material according to claim 3, characterized in that: The method specifically comprises the following steps: Step 1: placing the dielectric material into a vacuum evaporation system and evacuating the system; Step 2: shielding the dielectric material with a baffle, opening the beam source baffles of one or more semiconductor material thin film raw materials at the same time, passing current to the beam source of one or more semiconductor material thin film raw materials at the same time, and heating the beam source; Step 3, opening the baffle shielding the dielectric material, and evaporating a semiconductor material film on the surface of the dielectric material; Step 4: After the evaporation is completed, the beam source current of one or more semiconductor material thin film raw materials is disconnected simultaneously, and after the temperature drops to room temperature, the dielectric material with the surface evaporated semiconductor material thin film is taken out to obtain the dielectric material with the surface evaporated semiconductor material thin film.

5. The method for suppressing localized charging of the surface of a dielectric material according to claim 4, characterized in that: In step 1, the vacuum is evacuated until the pressure in the vacuum evaporation system is less than or equal to 4×10 -4 Pa.

6. The method for suppressing localized charging of the surface of a dielectric material according to claim 1, characterized in that: The purity of the raw materials of the semiconductor material film is greater than or equal to 95wt.%.

7. The method for suppressing localized charging of the surface of a dielectric material according to claim 1, characterized in that: The dielectric material is polyimide, polytetrafluoroethylene, alumina ceramic or glass.

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