Fabrication And Properties Of CVD-graphene-based Field-effect Transistors

Graphene has been getting increased attention because of its unique structure, unusual electrical and optical properties, good mechanical properties and thermal stability since its discovery in 2004. Basing on the transfer process of graphene films and the fabrication process of device, this paper aims at doing some research about the the influence mechanism that graphene film prepared via CVD(Chemical Vapor Deposition) process impact on the properties of graphene transistors, the results are as follows:1. Depending on the traditional PMMA aqueous method shift, we have introduced the graphene which comes from the back of oxygen plasma etching copper foil, HCl and H2O2 mix solution as well as metal copper attached to the grapheme surface eliminated by NH3·H2O are lead up, the oxide compounds of copper are included. what’s more, we have arrived at the conclusion that it can effectively removes the fold of the graphene surface by replacing the hydrone with the isopropyl alcohol or formamide. Using the shift craft optimized it can lead the CVD graphene film to transfer to the goal substrate perfectly, and the film transferred is clean and non-damaged. by comparison to the traditional PMMA aqueous method shift, the Dirac point of GNRFET is obviously reduced(reducing the p dping), and the mobility is remarkably enhanced(reducing the impurity scattering).2. we have systematically studied the influence rule of GNRFET fabrication process on the properties of device, and reach that in the photoetching craft it can reduce the residual of photoresist on the graphite alkene by using the suitable exposure, Moreover electrode is easier to strip after growth; In the process of dry etching, it can prevent the denaturation of photoresist because of oxygen plasma, or it will make photoresist remained in the etch process, and then can seriously influence the electrical contact between graphene and electrode; In addition, it can further reduce the residual photoresist which is binded to the graphene surface, and come the increase of mobility and the decrease of p doping as well as contact resistance.3. By the length transmission law we have studied the influence rule of Metal electrode materials on the contact resistance of GNRFET and the carrier mobility, The result indicates that the component has the smallest contact resistance and the greatest mobility when Ni is as the electrode while Sn, Ti, and Ni three metal materials are simultaneous. Mainly it can be explained there exists the greatest difference between Ni and Graphene work function in three metal materials, while the transmission probability of electron from the electrode to the graphite will increase with the gap of electrode and Graphene work function, and then he contact resistance will reduce, any further the mobility of GNRFET will enhance. So it can effectively improve the performance of Graphene work function if we choose the metal material as electrode which is greatest different from Graphene work function.