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US 7,550,783 B2Granted
Wide bandgap HEMTs with source connected field plates
AssigneeCree, Inc.
InventorsYifeng Wu, Primit Parikh, Umesh Mishra, Marcia Moore
Life of this patent
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Abstract
A HEMT comprising a plurality of active semiconductor layers formed on a substrate. Source electrode, drain electrode, and gate are formed in electrical contact with the plurality of active layers. A spacer layer is formed on at least a portion of a surface of said plurality of active layers and covering the gate. A field plate is formed on the spacer layer and electrically connected to the source electrode, wherein the field plate reduces the peak operating electric field in the HEMT.
Claims22
A high electron mobility transistor (HEMT), comprising:
- a plurality of active semiconductor layers;
- a two dimensional electron gas (2DEG) at the heterointerface between two of said plurality of active layers;
- source and drain electrodes in contact with said 2DEG;
- a gate formed between said source and drain electrodes and on said plurality of active layers;
- a spacer layer covering substantially all of the surface of said plurality of active layers between said gate and said source and at least part of the surface of said plurality of active layers between said gate and said drain electrode;
- a field plate on said spacer layer;
- and
- at least one conductive structure electrically connecting said field plate to said source electrode, said at least one conductive structure comprising one or more conductive buses running between said field plate and said source electrode on the topmost surface of said spacer layer and covering less than all of the topmost surface between said gate and said source electrode, said spacer layer providing electrical isolation between said plurality of active layers and said conductive buses.
5 more elements
A high electron mobility transistor (HEMT), comprising:
- a buffer layer and barrier layer formed successively on a substrate, said barrier layer having a top surface;
- a two dimensional electron gas (2DEG) at the heterointerface between said buffer layer and said barrier layer;
- source and drain electrodes both making ohmic contact with said 2DEG;
- a gate on said barrier layer between said source and drain electrodes;
- a spacer layer covering said surface of said barrier layer between said gate and said source, and at least a portion of said barrier layer between said gate and drain electrode;
- and
- a field plate on said spacer layer isolated from the barrier layer and extending a distance Lf from said gate toward said drain electrode, said field plate electrically connected to said source electrode by at least one of said conductive buses over and covering less than all of the topmost layer between said gate and source electrode, said spacer layer providing electrical isolation between said barrier layer and said at least one conductive structure.
4 more elements
A high electron mobility transistor (HEMT), comprising:
- a plurality of active semiconductor layers formed on a substrate;
- a two dimensional electron gas (2DEG) at the heterointerface between two of said plurality of active layers;
- source and drain electrodes in contact with said 2DEG;
- a gate between said source and drain electrodes and on said plurality of active layers;
- a field plate extending a distance Lf from the edge of said gate to said drain electrode, said field plate isolated from said gate and active layers;
- at least one conductive path electrically connecting said field plate to said source electrode, each of said at least one conductive path running outside of said active semiconductor layers;
- and
- a spacer layer covering the surface of said plurality of active layers between said gate and said source, each of said at least one conductive path electrically isolated from said active semiconductor layers, said spacer layer further comprising at least one conductive bus on said spacer layer and running between said field plate and said source electrode, wherein said at least one conductive bus covers less than all of the topmost surface of said spacer layer between gate and source electrode.
5 more elements
A high electron mobility transistor (HEMT), comprising:
- a plurality of active semiconductor layers;
- a two dimensional electron gas (2DEG) at the heterointerface between two of said plurality of active layers;
- source and drain electrodes in contact with said 2DEG;
- a gate formed between said source and drain electrodes and on said plurality of active layers;
- a spacer layer covering substantially all of the surface of said plurality of active layers between said gate and said source and at least part of the surface of said plurality of active layers between said gate and said drain electrode;
- a field plate on said spacer layer;
- and
- at least one conductive structure electrically connecting said field plate to said source electrode, said at least one conductive structure comprising two or more conductive buses running between said field plate and said source electrode on the topmost surface of said spacer layer and covering less than all of the topmost surface between said gate and said source electrode such that parasitic capacitance is reduced compared to a device wherein the entire topmost surface between said gate and said source electrode is covered, said spacer layer providing electrical isolation between said plurality of active layers and said conductive buses.
5 more elements
Dependencies are inferred from the claim text.