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US 7,592,211 B2Granted
Methods of fabricating transistors including supported gate electrodes
AssigneeCree, Inc.
InventorsScott T. Sheppard, Scott Allen
Life of this patent
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Abstract
Transistors are fabricated by forming a protective layer having an opening extending therethrough on a substrate, and forming a gate electrode in the opening. A first portion of the gate electrode laterally extends on surface portions of the protective layer outside the opening, and a second portion of the gate electrode is spaced apart from the protective layer and laterally extends beyond the first portion. Related devices and fabrication methods are also discussed.
Claims13
A method of fabricating a transistor, the method comprising:
- forming a first layer, wherein the first layer comprises a dielectric material;
- forming a second layer on the first layer, wherein the second layer has a hole therein exposing a portion of the first layer;
- forming a first opening extending through the first layer using the second layer as a mask;
- after forming the first opening, widening the hole in the second layer to form a second opening exposing the first opening and exposing surface portions of the first layer on opposite sides of the first opening;
- and
- forming a gate electrode in the first and second openings, wherein first portions of the gate electrode extend on surface portions of the first layer outside the first opening and second portions of the gate electrode extend on surface portions of the second layer outside the second opening.
3 more elements
A method of fabricating a transistor, the method comprising:
- forming a channel layer;
- forming a barrier layer on the channel layer, wherein a junction between the channel layer and the barrier layer define a heterojunction;
- forming a protective layer on the barrier layer, the protective layer having an opening extending therethrough;
- forming first and second ohmic contact regions on the barrier layer adjacent to and spaced apart from the protective layer so that the protective layer is between the first and second ohmic contact regions;
- and
- forming a gate electrode extending through the opening in the protective layer to contact the barrier layer and so that a first portion of the gate electrode laterally extends on surface portions of the protective layer outside the opening and so that a second portion of the gate electrode spaced apart from the protective layer laterally extends beyond the first portion,
- wherein forming the first and second ohmic contact regions comprises:
- patterning the protective layer to expose portions of the barrier layer;
- forming ohmic metal regions on the exposed portions of the barrier layer adjacent to and spaced apart from the patterned protective layer;
- and
- annealing the ohmic metal regions.
8 more elements
Dependencies are inferred from the claim text.