CN212587426U - Parallel RF MEMS switch based on structure ultra-smoothness - Google Patents

Abstract

The utility model provides a based on super smooth parallelly connected RF MEMS switch of structure, including basement, drive part, insulating layer and sliding part, wherein, the drive part is arranged in the basement, the drive part with the basement surface parallel and level and keep nanometer level and smooth; the sliding component is provided with a charging dielectric layer and an atomic-level smooth super-sliding surface, is in contact with the insulating layer through the super-sliding surface and is arranged on the insulating layer; the sliding component can be driven to slide in the horizontal direction in the surface, and the switch is realized by adjusting the overlapping and the separation of the driving component and the sliding component in the vertical surface.

Description

Parallel RF MEMS switch based on structure ultra-smoothness

Technical Field

The utility model belongs to the technical field of radio frequency micro-electromechanical system Switch (RF MEMS Switch), concretely relates to parallelly connected RF MEMS Switch based on structure is super smooth.

Background

With the development of radar and wireless communication technologies, small-sized, low-power consumption, high-performance, and multifunctional radio frequency devices are becoming the development trend in the radio field, radio frequency devices are developing towards miniaturization and integration, and MEMS switches are coming, and RF MEMS switches have gradually replaced the conventional GaAs FET switches and become the development direction of radio frequency switches (RF switches). Compared with the traditional switch, the RF MEMS switch has the advantages of lower insertion loss, higher isolation, better linearity, lower power consumption, smaller volume and the like, can be easily integrated with an IC circuit, and has wide application prospect. At present, the conventional RF MEMS switch mainly includes an electrostatic driving mechanism, a thermal driving mechanism, an electromagnetic driving mechanism, a piezoelectric driving mechanism, and the like in terms of driving modes.

As a basic electronic component, the RF MEMS electrostatic switch has characteristics of low power consumption, low insertion loss, low crosstalk, high isolation, high linearity, and the like, compared to conventional P-I-N diode switches and FET field effect thyristor switches, and is considered to be one of the most important MEMS devices. Particularly, with the rapid development of a 5G communication system, a radar system, a satellite communication system, and a high performance RF chip system in recent years, the industry has raised higher requirements on power consumption, reliability, isolation, linearity, power handling capability, and the like of an underlying RF switch device, for example, an LTE-a antenna switch having a carrier aggregation function in the 5G system must meet a requirement that IIP3 is 90dBm, while an RF-MEMS RF switch is the only one capable of achieving IIP3>90 dBm. Since conventional solid-state semiconductor switches (P-I-N and FETs) rely on doped carrier conduction and the presence of contact barriers, the switches exhibit poor quality factor (Ron × Coff) and leakage current in the off-state, which severely affects the insertion loss, isolation, linearity of the switch, making such switches unsuitable for switching of high frequency radio frequency signals. The RF MEMS electrostatic switch conducts radio frequency signals by means of mechanical contact, physical isolation exists between signal lines, and therefore the RF MEMS electrostatic switch has low power consumption (nj), low insertion loss, high isolation degree and linearity, energy consumption and cost of a wireless communication system, a radar detection system and a satellite system can be greatly reduced, fidelity of radio frequency signal transmission is improved, and comprehensive performance of the system is remarkably improved. The development and application of the method become key technologies of advanced electronic equipment such as a wireless communication (5G) system, a radar system, a satellite system and the like.

Despite the advantages of RF MEMS electrostatic switches compared to widely used semiconductor radio frequency switches, the mechanical contact switching presents serious reliability problems. The contact or the insulating layer of the RF MEMS electrostatic switch is easy to damage in high-speed collision, so that the on-resistance is increased, a stronger heat effect is caused, the device fails, meanwhile, the damage of the insulating layer can also aggravate the accumulation of surface charges, and when the accumulation of the charges exceeds a critical value, the switch fails through self-electrostatic adsorption; the arc discharge of the contact point at the moment of disconnection can cause the melting of the contact point material, which causes the remarkable increase of the contact resistance and even the direct adhesion of the contact point and the conducting wire; when high-energy power passes through the switch, enough electrostatic force can be coupled between an upper contact and a lower contact or a polar plate, so that the switch is subjected to self-locking pull-in, the processing power of the RF MEMS electrostatic switch is usually below 1W, and the processing power of the semiconductor switch can reach 1-10W. The above is one of the main reasons affecting the reliability and application field of the RF MEMS, and the service life of the RF MEMS electrostatic switch is two orders of magnitude lower than that of the conventional semiconductor switch. In addition, the standard voltage used in the IC integrated circuit system is lower than 5V, and the driving voltage of the RF MEMS electrostatic switch is generally between 10V and 80V, which is one of the reasons why the RF MEMS electrostatic switch is rarely used in the wireless communication system of the mobile phone. In summary, improving power handling capability, reducing driving voltage, and improving reliability are key issues to be solved in further development of RF-MEMS electrostatic switches.

The research of the structure ultra-smooth technology is the phenomenon of no friction and no abrasion sliding between two or the same materials, and the initial research is limited to the ultra-smooth phenomenon of nano-scale, such as the ultra-smooth between multi-arm coaxial carbon nanotubes, the ultra-smooth between a nano probe and a two-dimensional material, and the like. In 2013, zhengquan professor for the first time found the ultra-slip phenomenon between hopg (high Oriented cementitious graphite) sheet materials at micron scale, which marks the transition of ultra-slip from basic research to applicable technical research process. This is novel according to the structure super-smooth principle, has proposed a parallelly connected RF MEMS switch based on mechanism super-smooth, can reduce driving voltage and greatly improve the life and the power handling capacity of switch.

Disclosure of Invention

This is novel to utilize super smooth structure and level low friction between the foreign material, no sliding motion in the wearing surface, has proposed a parallelly connected RF MEMS switch based on structure super-smoothness. The radio-frequency signal transmission device comprises a substrate, a plurality of driving parts, an insulating layer and a sliding part with a charging medium layer, wherein when driving voltage is applied between the driving parts, the driving parts carry positive and negative opposite charges, the sliding part with the charging medium layer slides to the driving parts with the opposite charges under the action of charge force, at the moment, a large capacitor is formed between the driving parts and the sliding part, almost all radio-frequency signals are reflected, and transmission is cut off; when a reverse driving voltage is applied between the driving parts, positive and negative charges carried by the driving parts are exchanged, the sliding part slides to the other driving part under the action of the charges, at the moment, the front driving part and the sliding part have no direct area in the vertical direction, the capacitance is small, and the radio-frequency signal can be transmitted basically without loss.

Specifically, the novel parallel RF-MEMS switch is realized by the following scheme:

a parallel RF MEMS switch comprising a substrate, a driving part, an insulating layer and a sliding part, characterized in that: the driving member is disposed inside the substrate, the insulating layer has an atomically smooth surface, the sliding member has a charging dielectric layer and has a super-slip surface, and the sliding member is in contact with the atomically smooth surface of the insulating layer through the super-slip surface.

Further, the sliding component can be driven to slide in the horizontal direction in the surface, and the switch is realized by adjusting the overlapping and the separation of the driving component and the sliding component in the vertical surface.

Further, the driving component comprises a plurality of driving components, and preferably, the driving component comprises a first driving component and a second driving component.

Further, the driving part includes a driving electrode.

Further, the sliding member includes a dielectric layer and a graphite layer having a super-slip surface, and more preferably, the graphite layer is HOPG.

Further, the substrate is selected from an insulating material or a semiconductor material.

Further, the semiconductor material is preferably high group silicon; the insulating material is preferably selected from SiO2, SiC, sapphire, mica, and the like.

Further, the insulating layer is preferably a silicon oxide layer.

Further, the thickness of the insulating layer is in the nanometer level.

Further, the thickness of the insulating layer is preferably 2 to 50 nm.

Further, the driving manner in which the driving member drives the sliding member to slide in the horizontal direction in the plane is charge driving.

The novel sliding component is a sandwich structure which sequentially comprises a driving component, an insulating layer and a sliding component with a charging medium layer from bottom to top, so that the sliding component can slide in a plane with an extremely low friction force and without abrasion on the surface of the flat insulating layer; when in the off state, the capacitance between the sliding member and the driving member is extremely small, so that the radio frequency signal is hardly lost; when in the off state, the sliding component and the driving component form a larger capacitance due to the nanometer-scale thick insulating layer, and the radio-frequency signal is completely reflected. The on-off of the radio frequency switch can be controlled by setting a voltage control time sequence. Therefore, this novel because frictional force is extremely low and do not have wearing and tearing, can realize lower driving voltage, high life and power throughput, be expected to break through a main obstacle that restricts RFMEMS electrostatic switch life-span, impel its practicality process, promote the leap-over formula development of relevant electronic equipment research such as domestic wireless communication system (5G), high performance phased array radar and satellite communication system.

Drawings

FIG. 1 is a schematic diagram of the parallel RF-MEMS switch of the present application in a conducting state;

FIG. 2 is a top view of the parallel RF-MEMS switch of the present application in the on state;

FIG. 3 is a schematic diagram of a parallel RF-MEMS switch blocking state according to the present application;

FIG. 4 is a top view of the parallel RF-MEMS switch of the present application in the blocking state;

FIG. 5 is a cross-sectional view of a substrate with parallel RF-MEMS embedded actuation electrodes according to the present application.

Reference numerals: the device comprises a HOPG super sliding sheet, 2 insulating layers, 3 substrates, 4 first driving electrodes, 5 second driving electrodes and 6 charging medium layers.

Detailed Description

Embodiments of the invention are further described below with reference to the following drawings:

the ultra-smooth sheet is a part of an ultra-smooth pair in the prior art, the friction force between two contacted ultra-smooth surfaces of the existing ultra-smooth pair is almost zero when the two contacted ultra-smooth surfaces slide relatively, the friction coefficient is less than one thousandth, and the abrasion is zero.

As shown in fig. 1, the parallel RF-MEMS switch is composed of a high-resistance silicon substrate 3, a first driving electrode 4, a second driving electrode 5, a nanoscale insulating layer 2, a HOPG superslide sheet 1, and a charging medium layer 6 with positive charges. The first driving electrode 4 and the second driving electrode 5 are embedded in the substrate 3; the surfaces of the substrate 3, the first driving electrode 4 and the second driving electrode 5 are flush and keep nanoscale flatness; the insulating layer 2 covers the first driving electrode 4 and the second driving electrode 5 and is used for insulating the HOPG super sliding sheet from the first driving electrode 4 and the second driving electrode 5, the thickness of the insulating layer 2 is controlled to be 2nm-50nm, and the gap is used for ensuring smaller excitation voltage. The HOPG ultra-smooth sheet with the charging medium layer 6 is placed on the insulating layer to form an ultra-smooth contact pair with the insulating layer 2, the initial position of the ultra-smooth contact pair is opposite to the first driving electrode 4, and a certain amount of charges are filled in the charging medium layer 6. Because the HOPG super-slip sheet 1 with the charging dielectric layer has an atomic-level smooth super-slip surface, the HOPG super-slip sheet can slide on the surface of the insulating layer 2 with extremely low friction force without abrasion, meanwhile, the HOPG super-slip sheet does not generate adhesion failure due to charge accumulation on an electrode, and the ultra-long service life can be realized.

The working flow of the parallel RF-MEMS switch is as follows: fig. 1 and 2 show that the rf switch is in a conducting state, and at this time, since there is no overlapping area between the HOPG super-slip sheet 1 with the positively charged dielectric layer 6 and the second driving electrode 5 in the vertical direction, the capacitance is close to zero, and the rf signal can completely pass through without reflection loss. As shown in fig. 3 and 4, when a driving voltage is applied between the first driving electrode 4 and the second driving electrode 5, the first driving electrode 4 has a positive charge, the second driving electrode 5 has a negative charge, and at this time, the HOPG super-slip sheet 1 slides leftwards to above the first driving electrode 5 by the charge attraction force, and since the thickness of the insulating layer 2 is in the nanometer level, a large capacitance is formed between the HOPG super-slip sheet 1 and the second driving electrode 5, the radio frequency signal is completely reflected, and the transmission is cut off. When a reverse voltage is applied between the first driving electrode 4 and the second driving electrode 5, the first driving electrode 4 has a negative charge, the second driving electrode 5 has a positive charge, and at this time, the HOPG ultra-sliding sheet 1 slides above the first driving electrode 4 by the attraction of the charges to the right in the horizontal direction, as shown in fig. 1 and 2, at this time, the second driving electrode 5 and the HOPG ultra-sliding sheet 1 have no direct area in the vertical direction, the capacitance approaches zero, and the radio frequency signal can be transmitted through without loss.

Other embodiments can realize the in-plane continuous sliding of the HOPG super-sliding sheet by adjusting the number and the arrangement of the driving electrodes and the size of the HOPG super-sliding sheet.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment, but equivalent modifications or changes made by those skilled in the art according to the present invention should be included in the protection scope of the claims.

Claims (12)

1. A parallel RF MEMS switch comprising a substrate, a driving part, an insulating layer and a sliding part, characterized in that: the driving member is disposed inside the substrate, the insulating layer has an atomically smooth surface, the sliding member has a charging dielectric layer and has a super-slip surface, and the sliding member is in contact with the atomically smooth surface of the insulating layer through the super-slip surface.

2. The parallel RF MEMS switch of claim 1, wherein: the sliding component can be driven to slide in the surface plane of the substrate, and the switch is realized by adjusting the overlapping and the separation of the driving component and the sliding component in the vertical plane.

3. The parallel RF MEMS switch of claim 1, wherein: the driving component at least comprises a first driving component and a second driving component.

4. The parallel RF MEMS switch of claim 1, wherein: the driving part includes a driving electrode.

5. The parallel RF MEMS switch of claim 1, wherein: the sliding member includes a dielectric layer and a HOPG graphite layer having a super-slip surface.

6. The parallel RF MEMS switch of claim 1, wherein: the substrate is an insulating substrate or a semiconductor substrate.

7. The parallel RF MEMS switch of claim 6, wherein: the semiconductor substrate is a high-resistance silicon substrate.

8. The parallel RF MEMS switch of claim 7, wherein: the insulating substrate is preferably selected from the group consisting of SiO2, SiC, sapphire, mica substrates.

9. The parallel RF MEMS switch of any of claims 1-8, wherein: the insulating layer is a silicon oxide layer.

10. The parallel RF MEMS switch of any of claims 1-8, wherein: the thickness of the insulating layer is 1-100 nanometers.

11. The parallel RF MEMS switch of claim 10, wherein: the thickness of the insulating layer is 2-50 nanometers.

12. The parallel RF MEMS switch of any of claims 1-8, wherein: the sliding member is driven in a charge driving manner.

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