HIGH-ELECTRON-MOBILITY TRANSISTORS

• US 20160190297A1
• Filed: 03/07/2016
• Published: 06/30/2016
• Est. Priority Date: 12/27/2013
• Status: Active Grant

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Kudymov, Alexey, Ramdani, Jamal, Liu, Linlin
• Granted Patent: US 9,525,055 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/205 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/404 Multiple field plate structures
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 29/7786 with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET

Abstract

High-electron-mobility transistors that include field plates are described. In a first implementation, a HEMT includes a first and a second semiconductor material disposed to form a heterojunction at which a two-dimensional electron gas arises and source, a drain, and gate electrodes. The gate electrode is disposed to regulate conduction in the heterojunction between the source electrode and the drain electrode. The gate has a drain-side edge. A gate-connected field plate is disposed above a drain-side edge of the gate electrode and extends laterally toward the drain. A second field plate is disposed above a drain-side edge of the gate-connected field plate and extends laterally toward the drain.

Claims

1. A high-electron-mobility transistor (HEMT) comprising:

a first semiconductor material and a second semiconductor material disposed to form a heterojunction at which a two-dimensional electron gas arises;

a source electrode, a drain electrode, and a gate electrode, the gate electrode disposed to regulate conduction in the heterojunction between the source electrode and the drain electrode, the gate having a drain-side edge;

a vertical layered filed plate structure comprising at least one gate-connected field plate and at least one source connected field plate;

wherein, in the OFF state and at a potential difference between the source and the drain in excess of the absolute value of a gate swing amplitude, charge carriers are depleted from a portion of the heterojunction in a vicinity of the drain-side edge of at least one gate-connected field plate, the depletion of charge carriers effective to saturate a lateral electric field in the heterojunction in a vicinity of the drain-side edge of the gate electrode.

2. The HEMT of claim 1, wherein

the vertical layered filed plate structure comprises a first field plate having a drain-side edge;

a second field plate having a drain-side edge;

and a third filed plate having a drain-side edge.

3. The HEMT of claim 2, wherein

the first field plate is disposed above a drain-side edge of the gate electrode and extending laterally toward the drain;

the second field plate disposed above a drain-side edge of the first field plate and extending laterally toward the drain;

and the third filed plate disposed above a drain-side edge of the second field plate and extending laterally toward the drain.

4. The HEMT of claim 2, wherein

the first field plate is a gate-connected field plate,

the second filed plate is a gate-connected field plate, and

the third field plate is a source-connected filed plate.

5. The HEMT of claim 3, wherein the first field plate is connected to the gate electrode.

6. The HEMT of claim 3, wherein the second field plate is electrically connected to the first field plate via a gate member.

7. The HEMT of claim 2, wherein, in the OFF-state and at potential differences between the source and the drain that exceed a potential difference between the source and the drain at which charge carriers are depleted from a portion of the heterojunction in a vicinity of the drain-side edge of the second field plate, a portion of the heterojunction in a vicinity of the drain is depleted due to the vertically-oriented voltage difference between the heterojunction and the third field plate.

8. The HEMT of claim 2, wherein, in the OFF state:

a first electric field in the heterojunction extends drain-ward from a drain-side edge of the first field plate;

a second electric field in the heterojunction extends source-ward from a drain-side edge of the second field plate ; and

the first electric field first overlaps with the second electric field only at potential differences between the source and the drain that exceed a potential difference between the source and the drain at which charge carriers are depleted from a portion of the heterojunction in a vicinity of the drain-side edge of the second field plate.

9. The HEMT of claim 1, wherein:

the HEMT includes one or more layers of insulating material above the first and second semiconductor material;

a sheet carrier density arises at the heterojunction; and

after a steady state is reached after extended operation at specified operational parameters, a number of number of charge defects per unit area in the layers of insulating material is less than the sheet carrier density.

10. The HEMT of claim 1, wherein the drain-side edge of the second field plate is vertically separated from the second semiconductor material by the layers of insulating material.

11. The HEMT of claim 1, wherein second field plate has a rectangular cross-section and a bottom.

12. The HEMT of claim 1, wherein the electric field between second field plate and the heterojunction are highest at bottom, drain-side edge under certain bias conditions.

13. The HEMT of claim 1, wherein the first and second semiconductor materials are GaN and AlGaN, respectively.