Preparation method of large on-off ratio field effect transistor

Abstract

The invention discloses a preparation method of a large on-off ratio field effect transistor. The preparation method is characterized by comprising the following steps: (1) preparing graphene sheets and a tungsten disulfide sheet according to a mechanical exfoliation method, selecting a monocrystalline silicon wafer with an oxidation layer to serve as a substrate, and transferring one graphene sheet, the tungsten disulfide sheet and the other graphene sheet on the substrate sequentially to form a graphene heterojunction; and (2) uniformly coating photoresist in a spinning manner on the graphene heterojunction, transferring patterns on a mask onto the photoresist via exposure, and depositing Ti / Au metal via electron beam vapor deposition to obtain Ti / Au electrodes, so as to obtain the tunneling field effect transistor based on the graphene heterojunction. As the high carrier mobility of graphene and band gaps of transition metal dichalcogenides are taken into consideration, and the heterojunction of graphene and tungsten disulfide is taken as a channel material, the prepared field effect transistor is high in response speed and large in on-off ratio.

Description

technical field [0001] The invention relates to the application field of nano-electromechanical systems (NEMS), in particular to a method for preparing field-effect transistors with large switching ratios that can be used in digital logic circuits. Background technique [0002] Graphene is carbon atoms with sp 2 Orbital hybridization forms a planar film with a hexagonal honeycomb lattice, which possesses unique mechanical and electrical properties. Its high electron mobility, quantum Hall effect at room temperature, ballistic transport, and spin-polarized transport have great application potential in the future microelectronics field, and it is likely to replace silicon as an ideal material for next-generation transistors. At present, the most mature device concept of graphene in the field of microelectronics is the graphene field effect transistor. The two most promising application directions of this structure are digital logic circuits and radio frequency circuits. A...

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Problems solved by technology

However, after testing, it was found that when the transition metal sulfide is transferred to the substrate, its carrier mobility is only a few hundred cm 2 V –1 s – 1 , while transferred to a SiO 2 substrate, single-layer graphene can still reach 10,000 cm 2 V –1 s –1 , the carrier mobility has a great influence on the response speed of the transistor, so the relatively small carrier mobility is not conducive to the wide application of transition metal sulfide-based field effect transistors

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