Graphene or carbon nanotube devices with localized bottom gates and gate dielectric

A method of fabricating a transistor device, comprising the steps of:

• providing a substrate having an insulator thereon;
• forming a local bottom gate in a trench in the insulator;
• forming a local gate dielectric on the bottom gate;
• forming a carbon-based nanostructure material over at least a portion of the local gate dielectric, wherein a portion of the carbon-based nanostructure material serves as a channel of the device;
• and
• forming conductive source and drain contacts to one or more portions of the carbon-based nanostructure material on opposing sides of the channel that serve as source and drain regions of the device.

A method of fabricating a transistor device, comprising the steps of:

• providing a wafer having a layer of electrically conductive material on an insulating layer;
• forming cavities in the wafer to isolate one or more portions of the conductive material, wherein an isolated portion of the conductive material serves as a local bottom gate of the device;
• filling the cavities with a dielectric;
• forming a gate dielectric on the bottom gate;
• forming a carbon-based nanostructure material over at least a portion of the gate dielectric, wherein a portion of the carbon-based nanostructure material serves as a channel of the device;
• and
• forming conductive source and drain contacts to one or more portions of the carbon-based nanostructure material on opposing sides of the channel that serve as source and drain regions of the device.