Method of making devices including graphene layers epitaxially grown on single crystal substrates
View Patent ↗An electronic device comprises a body including a single crystal region on a major surface of the body. The single crystal region has a hexagonal crystal lattice that is substantially lattice-matched to graphene, and a at least one epitaxial layer of graphene is disposed on the single crystal region. In a currently preferred embodiment, the single crystal region comprises multilayered hexagonal BN. A method of making such an electronic device comprises the steps of: (a) providing a body including a single crystal region on a major surface of the body. The single crystal region has a hexagonal crystal lattice that is substantially lattice-matched to graphene, and (b) epitaxially forming a at least one graphene layer on that region. In a currently preferred embodiment, step (a) further includes the steps of (a1) providing a single crystal substrate of graphite and (a2) epitaxially forming multilayered single crystal hexagonal BN on the substrate. The hexagonal BN layer has a surface region substantially lattice-matched to graphene, and step (b) includes epitaxially forming at least one graphene layer on the surface region of the hexagonal BN layer. Applications to FETs are described.
1. A method of making a device comprising the steps of:
(a) providing a body including a single crystal, electrically insulative first region on a major surface of said body, said region having a hexagonal crystal lattice substantially lattice-matched to graphene, and
(b) epitaxially depositing at least one graphene layer on said first region; and
(c) forming a multi-layered, single crystal, electrically insulative second region on said at least one graphene layer, said second region having a hexagonal crystal lattice within each layer thereof and being substantially lattice-matched to graphene.
2. The method of claim 1 , wherein step (a) further includes the steps of (a1) providing a single crystal substrate of graphite and (a2) epitaxially forming multi-layered, single crystal hexagonal BN on said substrate, said hexagonal BN including said first region substantially lattice-matched to graphene, and step (b) includes epitaxially depositing said at least one graphene layer on said first region of said hexagonal BN layer.
3. The method of claim 2 , further including the step of: (c) after step (b), removing at least a portion of said graphite substrate.
4. The method of claim 1 , wherein step (a) includes providing said body having said first region so that the lattice-mismatch between said first region and said graphene layer is less than about 2%.
5. The method of claim 4 , wherein said first region and said at least one graphene layer have the same crystallographic space group.
6. The method of claim 1 , wherein said at least one graphene layer is deposited by MBE.
7. The method of claim 1 , wherein said at least one graphene layer is deposited by MBE from a vitreous carbon source.
8. The method of claim 1 , wherein said graphene layer is deposited by CVD.
9. The method of claim 1 for fabricating a FET, wherein steps (a) and (b) form said at least one graphene layer on an said electrically insulating first region of said body, and further including the steps of:
(d) forming source and drain regions,
(e) forming a channel region coupling said source and drain regions to one another, and
(f) forming a gate region configured to apply voltage to said channel region, thereby to control the flow of current between said source and drain regions, and
wherein step (e) forms said channel region to include a portion of said at least one graphene layer.