Study On The Mechanism Of PECVD In-Situ Growth Of Graphene Onthe Surface Of Insulatingmedium

Graphene is a new type of two-dimensional nanomaterials densely stacked with a single layer of carbon atoms.Since its discovery in 2004,graphene has attracted much attention.With the deepening of the research on graphene,more unique properties of graphene have been found,such as mechanical properties with good flexibility and mechanical strength;ultra-high thermal conductivity properties that can be used to solve chip heat dissipation problems in the integrated circuit industry and ultra-high carrier mobility at room temperature,that are different from traditional materials,so in recent years,graphene has become a star of two-dimensional materials.Now graphene has been used in electronic devices such as solar cells,super capacitors,and gas sensors.Graphene can also be applied to graphene field effect transistor devices.The application of graphene can improve the response speed and cut-off frequency of the device,so the research of graphene materials and their electronic devices is of great significance to the development of semiconductor devices.With the continuous development of the integrated circuit industry,the number of semiconductor field effect transistor devices per unit area has continued to increase,resulting in the integrated circuit industry has entered the nano-micro field.According to the development of Moore’s Law,the device size of field effect transistors must continue to shrink.The thickness of the gate insulation layer of the transistor becomes thinner as the device size decreases so the tunneling phenomenon of graphene field effect transistors may greatly increase and improve leakage loss.The most effective way to solve the basic size limitation of field effect transistor devices is to replace the traditional SiO₂with new high-k dielectric materials.Compared with SiO₂,Ta₂O₅has the advantage that the relative permittivity of SiO₂is 3.9 and the relative permittivity of Ta₂O₅is about 25.Ta₂O₅of the same thickness has a larger physical layer thickness than SiO₂,so it has a larger capacitance value and lower leakage current,the application prospect of Ta₂O₅in graphene field effect transistors is broader than that of low dielectric constant materials such as SiO₂.Ta₂O₅has high dielectric constant,high breakdown electric field and low leakage current so it can be used in graphene field effect transistors.The research topic is to study the mechanism of in-situ growth of graphene using PECVD technology on the surface of insulating substrate.Firstly,the Ta₂O₅high-k dielectric film was prepared by using electron beam vacuum coating system.The growth mechanism of the high-k film was divided into layer-by-layer growth mode,island growth mode and mixed growth mode.Secondly,the different in-situ growth temperatures on Ta₂O₅were studied.The influence of high-K thin films was obtained by orthogonal design experiments and Ta₂O₅high-k dielectric films can be prepared under the condition of in-situ temperature of 250℃,thickness of 150nm,and post-annealing temperature of 600℃.Thirdly graphene is grown in-situ on the Ta₂O₅high-k dielectric film by PECVD technology and two different growth mechanisms of graphene on metal catalyst substrates and insulating substrates are described in detail.Finally,the graphene film preparation experiment was completed at a bias voltage of 0V,25V,50V,75V,100V.Using optical microscope and Raman test,the process conditions were Ar flow 40sccm,CH₄flow 40sccm,H₂flow 2sccm,pressure is 110Pa,RF power is 150W,substrate temperature is 600°C,and the growth time is 1min30s,the graphene film with good film quality can be grown.