CN103943925B - A kind of full carbon coaxial line and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种全碳同轴线及其制备方法，属于集成电路技术领域。本发明利用石墨烯为单原子层厚，将石墨烯卷作圆柱体，构成半径很小（可以小到nm级别）的同轴线的内导体，同轴线内导体传导电流，同时，用单层或多层石墨烯来做同轴线的外导体构成电磁波在空间中的边界，利用氧化石墨来做内导体和外导体之间的介质材料，约束、引导电磁波能量的定向传输。本发明制得的同轴线的尺寸非常小，可以适用于射频、微波集成电路。

The invention discloses an all-carbon coaxial cable and a preparation method thereof, belonging to the technical field of integrated circuits. In the present invention, the graphene is single-atom-layer-thick, and the graphene is rolled into a cylinder to form an inner conductor of a coaxial line with a small radius (which can be as small as nm), and the inner conductor of the coaxial line conducts current. One or more layers of graphene are used as the outer conductor of the coaxial line to form the boundary of electromagnetic waves in space, and graphite oxide is used as the dielectric material between the inner conductor and the outer conductor to constrain and guide the directional transmission of electromagnetic wave energy. The size of the coaxial line prepared by the invention is very small and can be applied to radio frequency and microwave integrated circuits.

Description

Translated fromChinese

一种全碳同轴线及其制备方法A kind of all carbon coaxial line and preparation method thereof

技术领域technical field

本发明属于集成电路技术领域，具体涉及一种全碳同轴线及其制备方法。The invention belongs to the technical field of integrated circuits, and in particular relates to an all-carbon coaxial cable and a preparation method thereof.

背景技术Background technique

集成电路中用于晶体管间相互连接的线称为互连，在直流或低频情形下，不需要考虑互连线的分布效应和场效应。随着数字电路时钟速度、射频及微波电路工作频率的不断提升，这时不仅需要考虑互连线的分布效应，而且信号的能量除了包括导线内部电子运动的动能外，还包括导线周围空间中的电磁场能量，导线上的电流和周围空间或介质内的电磁场相互制约，使电磁能量在导线附近的电磁场中沿一定方向传播。如果仍然使用传统的互连线来传输高频信号则会导致信号的损耗、畸变过大。选择更合适的互连结构——传输线，则能获得仍有效工作于射频、微波频段的互连线。相较于传统的点对点互连线，传输线具有信号畸变更小、电磁辐射更少和串扰更少的优点，因而更适于高频下的信号传输。除了用于连接集成电路中的器件之外，传输线还广泛用于构成微波电路元件，如阻抗变换器、功分器、滤波器、谐振器、变压器、定向耦合器等。传输线的种类有很多，例如：平行双导线、同轴线、带状线、微带线、共面波导等。不同的工作频段，可以选择不同类型的传输线，选择的基本要求是：损耗小、效率高；尺寸合理、功率容量大；工作频带宽；尺寸小且均匀、结构简单易加工。The lines used for interconnection between transistors in integrated circuits are called interconnections. In the case of DC or low frequency, there is no need to consider the distribution effect and field effect of interconnection lines. With the continuous improvement of the clock speed of digital circuits and the operating frequency of radio frequency and microwave circuits, not only the distribution effect of interconnection wires needs to be considered, but also the energy of the signal includes not only the kinetic energy of electronic motion inside the wire, but also the energy in the space around the wire. The electromagnetic field energy, the current on the wire and the electromagnetic field in the surrounding space or medium restrict each other, so that the electromagnetic energy propagates in a certain direction in the electromagnetic field near the wire. If traditional interconnection wires are still used to transmit high-frequency signals, it will result in signal loss and excessive distortion. By choosing a more suitable interconnection structure——transmission line, an interconnection line that still works effectively in the radio frequency and microwave frequency bands can be obtained. Compared with traditional point-to-point interconnection lines, transmission lines have the advantages of less signal distortion, less electromagnetic radiation, and less crosstalk, so they are more suitable for signal transmission at high frequencies. In addition to connecting devices in integrated circuits, transmission lines are also widely used to form microwave circuit components, such as impedance converters, power dividers, filters, resonators, transformers, directional couplers, etc. There are many types of transmission lines, such as: parallel twin wires, coaxial lines, striplines, microstrip lines, coplanar waveguides, etc. Different types of transmission lines can be selected for different working frequency bands. The basic requirements for selection are: small loss, high efficiency; reasonable size, large power capacity; wide operating frequency band; small and uniform size, simple structure and easy processing.

目前用金属（铜、铝、钨、金等）来制备传输线存在着一些影响电路性能和可靠性的问题：(1)有的金属导体（如铜）需要额外淀积一层扩散阻挡层，而阻挡层材料的电阻率通常很高，这会引起传输线的总电阻增加（导致电路RC延迟、导体热损耗的增加），另外这层阻挡层还占用了传输线导体近20%的宽度，在导体平整化的过程中还会引起导体表面的凹陷，这会进一步增加导体的总电阻；(2)随着互连尺寸的减小，传输线中金属导体的截面与电子的平均自由程（～40nm）会处于同一数量级，这将大大增加导体表面和晶界对电子的散射，引起导体电阻的增加；(3)在金属线上较长时间地通过电流会引起金属离子的移动（电迁移效应），这最终会导致导线的断裂或与另一条导线的短路，造成电路的失效（电迁移的发生率取决于温度、晶体结构和平均电流密度）；(4)随着信号频率的升高，金属导体的趋肤效应也会导致导体电阻的增加、信号的衰减。At present, there are some problems affecting the performance and reliability of the circuit when using metals (copper, aluminum, tungsten, gold, etc.) to prepare transmission lines: (1) Some metal conductors (such as copper) need to deposit an additional diffusion barrier layer, while The resistivity of the barrier layer material is usually very high, which will increase the total resistance of the transmission line (resulting in the increase of circuit RC delay and conductor heat loss). In addition, this layer of barrier layer also occupies nearly 20% of the width of the transmission line conductor. The surface of the conductor will also be dented during the process of metallization, which will further increase the total resistance of the conductor; (2) As the interconnection size decreases, the cross-section of the metal conductor in the transmission line and the mean free path of electrons (~40nm) will change. In the same order of magnitude, this will greatly increase the scattering of electrons on the surface of the conductor and the grain boundary, causing an increase in the resistance of the conductor; (3) passing a current on the metal wire for a long time will cause the movement of metal ions (electromigration effect), which It will eventually lead to the breakage of the wire or the short circuit with another wire, resulting in the failure of the circuit (the occurrence rate of electromigration depends on the temperature, crystal structure and average current density); (4) As the signal frequency increases, the metal conductor The skin effect can also lead to an increase in conductor resistance and attenuation of the signal.

发明内容Contents of the invention

本发明的目的在于提出一种尺寸非常小的全碳同轴线及其制备方法。The purpose of the present invention is to propose a very small all-carbon coaxial cable and a preparation method thereof.

本发明的技术方案如下：Technical scheme of the present invention is as follows:

本发明利用石墨烯单原子层厚这一结构特点，将石墨烯卷作圆柱体，构成半径很小（可以小到nm级别）的同轴线的内导体，用石墨烯卷来做同轴线的内导体传导电流，同时，用单层或多层石墨烯来做同轴线的外导体构成电磁波在空间中的边界，利用氧化石墨来做内导体和外导体之间的介质材料，约束、引导电磁波能量的定向传输。The present invention utilizes the structural feature of graphene monoatomic layer thickness, rolls graphene into a cylinder to form the inner conductor of a coaxial line with a small radius (can be as small as nm level), and uses the graphene roll as a coaxial line The inner conductor conducts current. At the same time, single-layer or multi-layer graphene is used as the outer conductor of the coaxial line to form the boundary of electromagnetic waves in space. Graphite oxide is used as the dielectric material between the inner conductor and the outer conductor to constrain, Directed transmission of electromagnetic wave energy.

本发明全碳同轴线能够适用于射频、微波集成电路。The all-carbon coaxial cable of the invention can be applied to radio frequency and microwave integrated circuits.

本发明全碳同轴线的制备方法，包括以下步骤：The preparation method of the all-carbon coaxial cable of the present invention comprises the following steps:

(1)制备单层或多层石墨烯；(1) prepare monolayer or multilayer graphene;

(2)把单层或多层石墨烯卷曲成圆柱形构成同轴线的内导体；(2) Curling single-layer or multi-layer graphene into a cylindrical shape to form the inner conductor of the coaxial line;

(3)在同轴线内导体的表面淀积或包裹一层氧化石墨作为同轴线的内导体和外导体之间的介质材料；(3) Deposit or wrap a layer of graphite oxide on the surface of the inner conductor of the coaxial line as a dielectric material between the inner conductor and the outer conductor of the coaxial line;

(4)在上述氧化石墨的表面再包裹一层或多层石墨烯构成同轴线的外导体。(4) Wrap one or more layers of graphene on the surface of the above-mentioned graphite oxide to form the outer conductor of the coaxial line.

本发明的技术效果如下：Technical effect of the present invention is as follows:

(1)由于单层石墨烯的厚度只有0.34nm，即使是采用双层、多层石墨烯或者石墨片来制备同轴线，同轴线的尺寸仍旧可以很小（在同样尺寸情形下金属同轴线则有更高的电阻、更差的可靠性和更加困难的工艺过程），可以适用于射频、微波集成电路；(2)石墨烯结构稳定，用石墨烯制备同轴线不需要扩散阻挡层，制作工艺更加简单；(3)石墨烯的高电导率使得基于石墨烯的同轴线在高频下有更高的信号传输效率；(4)基于石墨烯的同轴线可以承受的最大电流密度高达10⁸A/cm²，具有十分优良的抗电迁移能力；(5)石墨烯具有优良的热传导性，可以缓解同轴线信号传输过程中局部温度过高而发生导线熔断或者介质热击穿的现象；(6)高频下，石墨烯不存在明显的趋肤效应，基于石墨烯的同轴线电阻在很宽的频带内都能保持不变，电路的性能也更加稳定。总之，基于石墨烯的同轴线有更好的传输性能和可靠性。(1) Since the thickness of single-layer graphene is only 0.34nm, even if a double-layer, multi-layer graphene or graphite sheet is used to prepare a coaxial line, the size of the coaxial line can still be very small (in the case of the same size, the metal coaxial line The axis has higher resistance, poorer reliability and more difficult process), which can be applied to radio frequency and microwave integrated circuits; (2) The structure of graphene is stable, and the preparation of coaxial lines with graphene does not require diffusion barriers (3) The high electrical conductivity of graphene makes the graphene-based coaxial line have higher signal transmission efficiency at high frequencies; (4) The graphene-based coaxial line can bear the maximum The current density is as high as 10⁸ A/cm² , and it has very good resistance to electromigration; (5) Graphene has excellent thermal conductivity, which can alleviate the occurrence of wire fusing or medium heat caused by excessive local temperature during coaxial signal transmission. (6) At high frequencies, graphene does not have an obvious skin effect, and the graphene-based coaxial line resistance can remain unchanged in a wide frequency band, and the performance of the circuit is more stable. In conclusion, graphene-based coaxial cables have better transmission performance and reliability.

附图说明Description of drawings

图1为本发明全碳同轴线结构示意图；Fig. 1 is the schematic diagram of the structure of the all-carbon coaxial line of the present invention;

图中：In the picture:

1——内导体 2——外导体1——inner conductor 2——outer conductor

3——内导体和外导体之间的介质材料3——The dielectric material between the inner conductor and the outer conductor

具体实施方式detailed description

下面通过实例对本发明做进一步说明。需要注意的是，公布实施例的目的在于帮助进一步理解本发明，但是本领域的技术人员可以理解：在不脱离本发明及所附权利要求的精神和范围内，各种替换和修改都是可能的。因此，本发明不应局限于实施例所公开的内容，本发明要求保护的范围以权利要求书界定的范围为准。The present invention will be further described below by example. It should be noted that the purpose of the disclosed embodiments is to help further understand the present invention, but those skilled in the art can understand that various replacements and modifications are possible without departing from the spirit and scope of the present invention and the appended claims of. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the protection scope of the present invention is subject to the scope defined in the claims.

可以采用单层、双层、多层石墨烯。基于石墨烯的全碳同轴线的具体制备过程如下：Single-layer, double-layer, and multi-layer graphene can be used. The specific preparation process of the graphene-based all-carbon coaxial line is as follows:

(1)碳基材料制备：获取所需的石墨烯（单层、双层、多层或者石墨片）可采用多种方法实现，例如：可以通过机械剥离、化学气相沉积、碳化硅表面外延生长、溶剂热合成等方法生成。(1) Preparation of carbon-based materials: Obtaining the required graphene (single layer, double layer, multilayer or graphite sheet) can be achieved by various methods, for example: mechanical exfoliation, chemical vapor deposition, epitaxial growth on the surface of silicon carbide , Solvothermal synthesis and other methods.

(2)同轴线内导体的制备：把石墨烯（单层、双层或多层）卷曲成圆柱形，范围为0.2nm～500nm，可以采用机械卷曲的方法，也可以把石墨烯放入去离子水、乙醇、丙酮、异丙醇等溶液中让其自卷形成石墨烯卷；(2) Preparation of the inner conductor of the coaxial line: curl the graphene (single layer, double layer or multilayer) into a cylindrical shape, the range is 0.2nm ~ 500nm, the method of mechanical curling can be used, or the graphene can be put into In deionized water, ethanol, acetone, isopropanol and other solutions, let it self-roll to form a graphene roll;

(3)氧化石墨的制备：氧化石墨可以通过使用氯酸钾和硝酸氧化石墨的方法得到，也可以通过使用高锰酸钾和硫酸氧化石墨的方法得到。(3) Preparation of graphite oxide: graphite oxide can be obtained by using potassium chlorate and graphite oxide nitric acid, or by using potassium permanganate and sulfuric acid graphite oxide.

(4)在同轴线内导体的表面淀积或包裹一层氧化石墨作为同轴线的内、外导体之间的介质，厚度范围为1nm～2000nm；(4) Deposit or wrap a layer of graphite oxide on the surface of the inner conductor of the coaxial line as the medium between the inner and outer conductors of the coaxial line, with a thickness ranging from 1nm to 2000nm;

(5)在上述氧化石墨的表面再包裹一层或多层石墨烯构成同轴线的外导体,厚度为0.34nm～100nm。(5) Wrapping one or more layers of graphene on the surface of the graphite oxide to form an outer conductor of the coaxial line, with a thickness of 0.34 nm to 100 nm.

虽然本发明已以较佳实施例披露如上，然而并非用以限定本发明。任何熟悉本领域的技术人员，在不脱离本发明技术方案范围情况下，都可利用上述揭示的方法和技术内容对本发明技术方案作出许多可能的变动和修饰，或修改为等同变化的等效实施例。因此，凡是未脱离本发明技术方案的内容，依据本发明的技术实质对以上实施例所做的任何简单修改、等同变化及修饰，均仍属于本发明技术方案保护的范围内。Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent implementation of equivalent changes example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (5)

1. a full carbon coaxial line, it is characterised in that be rolled into the cylinder inner wire as coaxial line with single or multiple lift Graphene,At the outside of described inner wire parcel monolayer or multi-layer graphene as the outer conductor of coaxial line, and described inner wire and outer conductor itBetween fill graphite oxide as dielectric material, described inner wire section radius is 0.2nm～500nm, and described dielectric material thickness is1nm～2000nm, the thickness of described outer conductor is 0.34nm～100nm.

2. a preparation method for the full carbon coaxial line described in claim 1, comprises the following steps:

(1) single or multiple lift Graphene is prepared；

(2) single or multiple lift Graphene is curled into cylinder, constitutes the inner wire of coaxial line；

(3) described inner wire surface deposition or parcel one layer of graphite oxide as dielectric material；

(4) wrap up one or more layers Graphene on the surface of described graphite oxide again and constitute the outer conductor of coaxial line.

3. preparation method as claimed in claim 2, it is characterised in that described step is by mechanically pulling off in (1), chemistryVapour deposition, silicon carbide epitaxial growth or solvent process for thermosynthesizing generate single or multiple lift Graphene.

4. preparation method as claimed in claim 2, it is characterised in that the method using machine crimp in described step (2)Or Graphene put into deionized water, ethanol, acetone or aqueous isopropanol any one in, allow it form coaxial line from volumeInner wire.

5. preparation method as claimed in claim 2, it is characterised in that in described step (3), graphite oxide is by using chlorineThe method of acid potassium and nitric acid oxidation graphite obtains, or is prepared by the method using potassium permanganate and sulfuric acid oxidation graphite.