Graphene, a one carbon atom thick material, has a very high carrier mobility, making it suitable for use in high speed, high performance electronic devices. Current trends towards feature size scaling generally involve use of a high-k dielectric in these scaled graphene-based devices.
However, nucleation of high-k dielectrics on carbon-based materials such as graphene is problematic since bonding of the dielectric occurs by electrostatic forces. Specifically, carbon-based materials with honeycomb crystalline structures like graphene are chemically inert. The inertness makes it almost impossible to uniformly coat a thin layer of any material onto the carbon surface. Deposited material will only form clumps or clusters on the carbon surface rather than a uniform coating. While a uniform coating can eventually be achieved by adding more of the material, depositing enough material to gain complete coverage results in a layer that is too thick for some applications. This is the case with thin materials such as high-k dielectrics.
A conventional solution to this problem is to use nitrogen dioxide functionality to facilitate the bonding by exposing the carbon-based material to nitrogen dioxide gas prior to high-k dielectric deposition. This technique, however, shows degraded device performance due to low electron mobility. Namely, it has been suggested that a dipole forms at the interface of the dielectric and the carbon-based material, degrading device performance.
Therefore, techniques that improve nucleation of a thin coating of materials, such as high-k dielectrics, on carbon-based materials, such as graphene, without degrading device performance would be desirable.
USPTO Backgrounds
USPTO Backgrounds