Article comprising an oxide layer on a GaAs-based semiconductor structure and method of forming same
View Patent ↗A compound semiconductor structure is provided, which includes a GaAs-based supporting semiconductor structure having a surface on which a dielectric material is to be formed. A first layer of gallium oxide is located on the surface of the supporting semiconductor structure to form an interface therewith. A second layer of a Ga—Gd oxide is disposed on the first layer. The GaAs-based supporting semiconductor structure may be a GaAs-based heterostructure such as an at least partially completed semiconductor device (e.g., a metal-oxide field effect transistor, a heterojunction bipolar transistor, or a semiconductor laser). In this manner a dielectric layer structure is provided which has both a low defect density at the oxide-GaAs interface and a low oxide leakage current density because the dielectric structure is formed from a layer of Ga 2 O 3 followed by a layer of Ga—Gd-oxide. The Ga 2 O 3 layer is used to form a high quality interface with the GaAs-based supporting semiconductor structure while the Ga—Gd-oxide provides a low oxide leakage current density.
1. A method of forming a dielectric layer structure on a supporting semiconductor structure comprising the steps of:
providing a compound semiconductor-based supporting structure having a first surface;
providing a beam of oxide;
depositing a first layer of oxide on said first surface using said beam of oxide wherein said first layer of oxide has a second surface;
providing a beam of metal and a beam of oxygen; and
depositing a second layer of oxide on said second surface simultaneously using said beam of oxide, said beam of metal, and said beam of oxygen.
2. The method of claim 1 wherein the step of providing said beam of oxide includes providing a beam of gallium oxide.
3. The method of claim 1 wherein said beam of oxide is provided by a first effusion cell.
4. The method of claim 1 wherein the step of providing said beam of metal includes providing a beam of Gd.
5. The method of claim 1 wherein said beam of metal is provided by a second effusion cell.
6. The method of claim 1 wherein the step of providing said beam of oxygen includes providing a beam of molecular oxygen.
7. The method of claim 1 wherein said beam of oxygen is provided by a plasma source.
8. The method of claim 1 wherein said first layer of oxide comprises gallium oxide.
9. The method of claim 1 wherein said second layer of oxide comprises Ga—Gd-oxide.
10. The method of claim 1 wherein said second layer of oxide comprises Gd 3 Ga 5 O 12 .
11. The method of claim 1 wherein said compound semiconductor-based supporting structure comprises a GaAs based semiconductor structure.
12. The method of claim 1 wherein said compound semiconductor-based supporting structure comprises epitaxial layers.
13. A method of forming a dielectric layer structure on a supporting semiconductor structure comprising the steps of:
providing a compound semiconductor-based supporting structure having a first surface;
providing a beam of oxide and providing a beam of oxygen;
depositing a first layer of oxide on said first surface simultaneously using said beam of oxide and said beam of oxygen wherein said first layer of oxide has a second surface;
providing a beam of metal; and
depositing a second layer of oxide on said second surface simultaneously using said beam of oxide, said beam of metal, and said beam of oxygen.