Preparation Of Graphene Film On Insulating Substrate And Itsapplication In Electronic Devices

Graphene,a new type of two-dimensional electronic material,has great widely application value in the electronic information field due to its high carrier mobility and light transmission properties,such as supercapacitors,field effect transistors,and thin film sensors.Due to its advantages of high carrier mobility,cutoff frequency,and response speed,graphene field effect transistors is most likely to replace silicon and be come the next generation of semiconductor material.Chemical vapor deposition?CVD?methods have currently become the most suitable process for preparing graphene.In recent years,with the gradual deepening of research on the preparation of graphene using CVD process,it has further promoted the research and application of graphene material and electronic device.However,the related research on the preparation of high-quality graphene using technologies compatible with the current silicon integrated circuit fabrication process is still a difficult point,which also limits the application and development of graphene in the electronic information field.On the other hand,the conventional graphene device basically uses a low dielectric constant SiO₂ as an insulating dielectric layer,the gate voltage has weak controllability for carriers,and easily happen the tunneling phenomenon in this graphene device.The high-k insulated layer?Ta₂O₅,HfO₂,h-BN etc.?can have a strong gate electric-field control effect on the carriers in the graphene and reduce the impact of its ionized impurity scattering,making the device obtain high carrier mobility,response speed and improve device performance.In this paper,low-temperature PECVD technology was used to prepare large,uniform-area graphene on metal substrates and insulating substrates respectively,and studied the effect of nickel film structure and surface morphology on the growth of graphene,as well as the effect of gas composition and flow on the growth and transfer of graphene on the insulating substrate.On this basis,the preparation of GFET device with high-k Ta₂O₅ as the back-gate insulating layer was completed,which includes:the design of devices and masks,the optimization of materials and preparation processes and the performance of device,etc.The results of device properties shows:At room temperature,the transfer characteristic is unipolar hole-conducting feature with the carrier mobility of1836 cm²/?v·s?and the on-off ratio of 6.8.Through annealing,the device restores bipolar conductive characteristics.The P-type doping effect is reduced,the Dirac voltage decreases,and the carrier mobility increases.Among them,after annealing at 100°C,the mobility and switching ratio is improved to 2836 cm²/?v·s?and 8.3,respectively,which is beneficial to the improve the performance of device.At the same time,compared with the conventional SiO₂ insulating dielectric layer,the carrier mobility of graphene device fabricated with Ta₂O₅ as high-k insulating dielectric layer has increased from 1214cm²/?v·s?to 2836 cm²/?v·s?,which electrical performance is better improved.