Dielectric passivation for semiconductor devices
AssigneeCree, Inc.
InventorsRichard Peter Smith, Scott T. Sheppard, John Williams Palmour
Life of this patent
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Abstract
A semiconductor device is disclosed that includes a layer of Group III nitride semiconductor material that includes at least one surface, a control contact on the surface for controlling the electrical response of the semiconductor material, a dielectric barrier layer covering at least a portion of the one surface adjacent the control contact, the dielectric barrier layer having a bandgap greater than the bandgap of the Group III nitride and a conduction band offset from the conduction band of the Group III nitride; and a dielectric protective layer covering the remainder of the Group III nitride surface.
Claims49
A semiconductor device comprising:
- a layer of Group III nitride semiconductor material that includes at least one surface;
- a control contact on said surface for controlling the electrical response of said semiconductor material;
- an ohmic contact on said surface for providing a conductive path through the device;
- a dielectric barrier layer having a thickness between about 5 nm and about 200 nm covering said surface between said control contact and said ohmic contact, said dielectric barrier layer having a bandgap greater than the bandgap of said Group III nitride and a conduction band offset from the conduction band of said Group III nitride;
- and
- a dielectric protective layer covering said barrier layer, said dielectric protective layer having a bandgap narrower than the bandgap of said dielectric barrier layer and greater than the bandgap of said Group III nitride.
A semiconductor device comprising:
- a layer of Group III nitride semiconductor material that includes at least one surface;
- a control contact directly adjacent said surface for controlling the electrical response of said semiconductor material;
- an ohmic contact on said surface for providing a conductive path through the device;
- an aluminum nitride barrier layer covering said surface between said control contact and said ohmic contact, for providing a bandgap greater than the bandgap of said Group III nitride and a conduction band offset from the conduction band of said Group III nitride;
- a spacer layer interposed between said Group III nitride surface and said aluminum nitride barrier layer for physically protecting said Group III nitride surface and for reducing surface charge accumulation, said spacer layer at least partially covering the surface of said control contact;
- and
- a silicon nitride protective layer covering said barrier layer for providing a physical and chemical barrier against moisture, oxygen and related environmental attack.
A method of passivating a Group III nitride semiconductor device having a control contact and at least one ohmic contact, comprising:
- covering the Group III nitride surface between the control contact and the ohmic contact with a dielectric barrier layer having a bandgap greater than the bandgap of the Group III nitride, a conduction band that is offset from the conduction band of the Group III nitride, and having a thickness between about 5 nm and about 200 nm;
- and
- forming a protective layer on said barrier layer from a dielectric material having a bandgap narrower than the bandgap of the barrier layer and that also provides a physical and chemical barrier against moisture and oxygen.
A method of passivating a Group III nitride semiconductor device having a control contact and at least one ohmic contact that are both located directly adjacent semiconductor material in which electrical conduction occurs, comprising:
- forming a spacer layer on the surface of the Group III nitride semiconductor device such that the spacer layer covers at least a portion of the surface of said control contact;
- covering the spacer layer between the control contact and the ohmic contact with a dielectric barrier layer having a bandgap greater than the bandgap of the Group III nitride and a conduction band that is offset from the conduction band of the Group III nitride;
- and
- forming a protective layer on said barrier layer from a dielectric material having a bandgap narrower than the bandgap of the barrier layer and that also provides a physical and chemical barrier against moisture and oxygen.
Dependencies are inferred from the claim text.