A field-effect transistor based on two-dimensional materials

Abstract

The present invention relates to a field-effect transistor fabricated from two-dimensional materials, comprising a substrate, a silicon dioxide dielectric layer having a recessed groove on its upper surface, and a two-dimensional material layer disposed on the silicon dioxide dielectric layer and covering the recessed groove. An organic material body is disposed at each end region of the two-dimensional material layer along the recessed groove, and a metal electrode is grown on each side region of the two-dimensional material layer perpendicular to the recessed groove. Compared to the prior art, the field-effect transistor of the present invention generates localized heating when irradiating the organic material, causing a polycondensation reaction in the organic material, thereby generating stress on the underlying two-dimensional material. This reduces the band gap of the two-dimensional material, increases electron mobility, and further enhances the performance of the two-dimensional material field-effect transistor. Furthermore, the preparation method is simple, and the product exhibits high electron mobility and excellent stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of two-dimensional materials and relates to a field effect transistor prepared based on two-dimensional materials. Background Art

[0002] In recent years, field-effect transistors (FETs) using two-dimensional layered semiconductor materials, such as molybdenum disulfide (MoS2), as channel materials have garnered increasing attention and research, being considered promising post-silicon materials. MoS2's wide bandgap (1.2 eV for bulk and 1.8 eV for monolayers) enables low static power consumption and a high on / off ratio. Furthermore, MoS2's two-dimensional planarity, while compatible with traditional semiconductor processes, effectively suppresses short-channel effects caused by size reduction.

[0003] When a two-dimensional material is stretched or compressed, the distances between its atoms change, causing corresponding changes in its band structure and electronic properties. Compared to other semiconductor materials, two-dimensional materials offer greater geometrical manipulability. By exploiting the strain-induced changes in the band structure and electronic properties of two-dimensional materials, the performance of field-effect transistors (FETs) using these materials can be improved.

[0004] Chinese patent 201610312907.0 discloses a two-dimensional material field effect transistor and a preparation method. The two-dimensional material field effect transistor has a conductive substrate, an insulating dielectric layer, a two-dimensional material, and a metal electrode from bottom to top. The preparation method of the present invention is a mechanical scratching method, that is, the two-dimensional material is first transferred to the insulating dielectric layer by a mechanical stripping method, and then the insulating dielectric layer and the two-dimensional material are evaporated with metal as a whole. The needle tip or blade is carefully manipulated under a microscope so that it just touches the surface of the two-dimensional material, and then the needle tip or blade is slowly moved to make it pass over the middle of the two-dimensional material to remove the metal above and form a channel. Continue to move the needle tip or blade to scratch out two metal electrodes, namely the source electrode and the drain electrode. However, the device performance of the field effect transistor prepared by this patent needs to be improved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a field effect transistor prepared based on two-dimensional materials to improve the performance of transistor devices.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A field effect transistor prepared based on two-dimensional materials includes a substrate arranged in sequence from bottom to top, a silicon dioxide dielectric layer with a lower groove on the upper surface, and a two-dimensional material layer arranged on the silicon dioxide dielectric layer and covering the lower groove. An organic material body is respectively provided at the two end regions of the two-dimensional material layer along the direction of the lower groove, and a metal electrode is respectively grown on the two side regions of the two-dimensional material layer along the direction perpendicular to the lower groove.

[0008] Furthermore, the substrate is made of silicon material and has a thickness of 100-500 μm.

[0009] Furthermore, the thickness of the silicon dioxide dielectric layer is 50-200 nm.

[0010] Furthermore, the material of the two-dimensional material layer is molybdenum disulfide.

[0011] Furthermore, the thickness of the two-dimensional material layer is within 2 nm.

[0012] Furthermore, the organic material body is made of low-density polyethylene and has a thickness of 10-200 nm.

[0013] Furthermore, the material of the metal electrode is gold, silver, aluminum, titanium or chromium.

[0014] Furthermore, the depth of the lower groove is 10-50 nm.

[0015] The working principle of the present invention is as follows: when a laser or electron beam irradiates an organic material body, the irradiation produces local heating of the organic material, causing the organic material to undergo condensation deformation, and then produces tensile stress on the two-dimensional material below, reducing the band gap width of the two-dimensional material and increasing the electron mobility, thereby improving the performance of the two-dimensional material field-effect transistor device.

[0016] Compared with the prior art, the present invention utilizes the stress generated by organic materials to improve the mobility and conductivity of two-dimensional material transistors, thereby improving device performance. Specifically, it has the following advantages:

[0017] (1) The two-dimensional material used in the present invention can effectively suppress the short channel effect caused by size reduction.

[0018] (2) The organic material used in the present invention is low-density polyethylene, which is more easily deformed when heated and generates tensile stress on the underlying two-dimensional material.

[0019] (3) The two-dimensional material used in the present invention will produce changes in the band structure when it is strained or subjected to stress, which will reduce the band gap width and increase the electron mobility, thereby improving the performance of the field effect transistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the field effect transistor of the present invention;

[0021] Figure 2 is a side view of a field effect transistor of the present invention;

[0022] Description of the marks in the figure:

[0023] 1-substrate, 2-silicon dioxide dielectric layer, 3-two-dimensional material layer, 4-organic material body A, 5-organic material body B, 6-metal electrode A, 7-metal electrode B. DETAILED DESCRIPTION

[0024] The embodiments described below with reference to specific examples, the embodiments herein and various features and related details will be more fully explained with reference to the non-limiting examples illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the embodiments herein. Conventional processes well known in semiconductor technology can be used when making the structures described. The examples used herein are merely intended to facilitate understanding of how the embodiments herein can be implemented and to further enable those skilled in the art to implement the embodiments herein. Therefore, the examples herein should not be construed as limiting the scope of the embodiments herein.

[0025] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0026] Example 1

[0027] A method for constructing a field-effect transistor based on two-dimensional materials:

[0028] First, a silicon material is used as the substrate 1, and the substrate 1 is cleaned. The thickness of the substrate is 500 μm.

[0029] Next, a silicon dioxide dielectric layer 2 is deposited on the substrate 1 to increase the adhesion between the silicon dioxide material and the substrate 1. The thickness of the silicon dioxide dielectric layer 2 is 70 nm.

[0030] Subsequently, anhydrous hydrofluoric acid is used to directly etch the center of the upper surface of the silicon dioxide dielectric layer 2 to form a lower groove with a depth of 30nm. Then, a two-dimensional material layer 3 of molybdenum disulfide covering the lower groove is covered on the surface of the silicon dioxide dielectric layer 2 by a transfer method. The thickness is 1nm.

[0031] Next, two 50 nm thick low-density polyethylene films, namely organic material body A4 and organic material body B5, were transferred to partial areas of the two-dimensional material layer 3 by a high-pressure method.

[0032] Finally, a 50 nm thick metal chromium film is deposited by electron beam evaporation, and then the metal is made into two electrode layers through a lift-off process, namely metal electrode A6 and metal electrode B7.

[0033] The resulting field-effect transistor is shown in Figure 1 and Figure 2 shown.

[0034] Example 2

[0035] A method for constructing a field-effect transistor based on two-dimensional materials:

[0036] First, silicon is used as the substrate 1, and the substrate 1 is cleaned.

[0037] A silicon dioxide dielectric layer 2 is deposited on the substrate 1 to increase the adhesion between the two-dimensional phase change material and the substrate 1. The thickness of the silicon dioxide dielectric layer 2 is 80 nm.

[0038] Afterwards, a lower groove with a depth of 50nm is etched in the center of the surface of the silicon dioxide dielectric layer 2 by ion etching; the lower groove is filled with positive photoresist, and then the photoresist is exposed to ultraviolet light; a layer of two-dimensional material layer 3 is grown by CVD method to cover the concave table surface. The two-dimensional material layer 3 is a single layer, using molybdenum ditelluride, with a thickness of 1nm; and the exposed positive photoresist is dissolved with a developer.

[0039] Then, two 50 nm thick low-density polyethylene films were transferred to partial areas of the two-dimensional material layer 3 by a vapor phase method, which were organic material body A4 and organic material body B5.

[0040] Finally, a 50 nm thick metal chromium film is deposited by electron beam evaporation, and then the metal is made into two electrode layers through a lift-off process, namely metal electrode A6 and metal electrode B7.

[0041] A schematic diagram of a method for improving the performance of two-dimensional material field effect transistor devices is shown below. Figure 1 、 Figure 2 shown.

[0042] Examples 3-6

[0043] Compared with Example 1, most of the aspects are the same, except that the metal electrodes in this embodiment are made of gold, silver, aluminum or titanium.

[0044] Example 7

[0045] Compared with Example 1, most of the features are the same, except that in this embodiment, the thickness of the substrate 1 is 100 μm, the thickness of the silicon dioxide dielectric layer 2 is 50 nm, and the thickness of the organic material body is 10 nm.

[0046] Example 8

[0047] Compared with Example 1, most of the parts are the same, except that in this embodiment, the thickness of the substrate 1 is 200 μm, the thickness of the silicon dioxide dielectric layer 2 is 200 nm, and the thickness of the organic material body is 200 nm.

[0048] Example 9

[0049] Compared with Example 1, most of the features are the same, except that in this example, the depth of the lower groove is 10 nm.

[0050] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A field effect transistor based on two-dimensional materials, characterized in that: The device comprises a substrate, a silicon dioxide dielectric layer having a lower groove on its upper surface, and a two-dimensional material layer arranged on the silicon dioxide dielectric layer and covering the lower groove, wherein an organic material body is respectively provided at both end regions of the two-dimensional material layer along the direction of the lower groove, and a metal electrode is respectively grown on both sides of the two-dimensional material layer along the direction perpendicular to the lower groove; The substrate is made of silicon material and has a thickness of 100-500 μm; The thickness of the silicon dioxide dielectric layer is 50-200 nm; The material of the two-dimensional material layer is molybdenum disulfide; The thickness of the two-dimensional material layer is within 2 nm; The organic material body is made of low-density polyethylene and has a thickness of 10-200 nm; The material of the metal electrode is gold, silver, aluminum, titanium or chromium; The depth of the lower groove is 10-50 nm.

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