Nitride semiconductor device, production method thereof, diode, and field effect transistor

Patent metadata

Field	Value
Publication number	US-9911842-B2
Application number	US-201615097888-A
Country	US
Kind code	B2
Filing date	Apr 13, 2016
Priority date	Oct 18, 2013
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A nitride semiconductor device includes; a semiconductor stack configured with a plurality of semiconductor layers made of nitride semiconductors provided on a base having a conductive portion; a first electrode provided on a portion of a semiconductor layer of the semiconductor layers configuring the semiconductor stack; a second electrode provided on a portion of a semiconductor layer of the semiconductor layers configuring the semiconductor stack separately from the first electrode; a first wiring provided at an upper layer of the first electrode; and a second wiring provided at an upper layer of the second electrode. A low permittivity area being a portion of which permittivity is lower than permittivities of the nitride semiconductors configuring the semiconductor stack at a lower layer of a portion of at least one of the first electrode and the second electrode other than a portion being junctioned with the semiconductor stack electrically.

First claim

What is claimed is:

1. A nitride semiconductor device comprising:
a base having, at least a portion thereof, a conductive portion;
a semiconductor stack configured with a plurality of semiconductor layers being made of nitride semiconductors provided on the base;
a first electrode provided on at least a portion of a semiconductor layer of the semiconductor layers configuring the semiconductor stack;
a second electrode provided on at least a portion of a semiconductor layer of the semiconductor layers configuring the semiconductor stack separately from the first electrode;
a first wiring provided at an upper layer of the first electrode;
a second wiring provided at an upper layer of the second electrode; and
a dielectric layer having a permittivity lower than permittivities of the nitride semiconductors configuring the semiconductor stack and being formed at a lower layer of a portion where at least one of the first electrode and the second electrode is disposed, the portion being other than a portion where the at least one of the first electrode and the second electrode is junctioned with the semiconductor stack electrically, wherein
the semiconductor stack has a configuration of partly producing a two-dimensional electron gas,
the dielectric layer and a two-dimensional-electron-gas-non-produced area, where the two-dimensional electron gas is not to be produced, are disposed so as to overlap within a plane, which is in parallel with a primary surface of the base, at the lower layer of the portion where at least one of the first electrode and the second electrode is disposed, the portion being other than the portion where the at least one of the first electrode and the second electrode is junctioned with the semiconductor stack, and
a perimeter portion of the dielectric layer along a width direction of the second electrode is configured to be outside a perimeter portion of the two-dimensional-electron-gas-non-produced area in the semiconductor stack.

2. The nitride semiconductor device according to claim 1 , wherein the dielectric layer contains at least one kind of element selected from a group consisting of silicon, oxygen, nitrogen, carbon, fluorine, and boron.

3. The nitride semiconductor device according to claim 1 , wherein the dielectric layer is made of a gap of which permittivity is lower than the permittivity of the nitride semiconductor configuring the semiconductor stack.

4. The nitride semiconductor device according to claim 1 , wherein, when a predetermined one, being provided with the dielectric layer at a lower layer thereof, of the first electrode and the second electrode is selected, the other one of the first electrode and the second electrode is configured to be identical to a conductive portion of the base in electric potential.

5. The nitride semiconductor device according to claim 1 , wherein the perimeter portion of the dielectric layer along the width direction of the second electrode is configured to be outside the perimeter portion of the two-dimensional-electron-gas-non-produced area within a range of equal to or greater than 0.5 μm and equal to or lower than 3.0 μm.

6. The nitride semiconductor device according to claim 1 , wherein the two-dimensional-electron-gas-non-produced area is configured with an area containing impurity in a portion of the semiconductor stack.

7. The nitride semiconductor device according to claim 1 , wherein the two-dimensional-electron-gas-non-produced area is configured with a recessed portion provided in a portion of the semiconductor stack.

8. The nitride semiconductor device according to claim 1 , wherein the electrode, being provided with the dielectric layer at the lower layer thereof, of the first electrode and the second electrode is an ohmic electrode.

9. The nitride semiconductor device according to claim 1 , wherein the semiconductor stack has a first semiconductor layer and a second semiconductor layer, the first semiconductor layer is made of a nitride semiconductor, and the second semiconductor layer is made of at least one kind of nitride semiconductor being formed on the first semiconductor layer and being broader than the first semiconductor layer in bandgap in average.

10. The nitride semiconductor device according to claim 9 , wherein the semiconductor stack includes a third semiconductor layer made of a nitride semiconductor being formed selectively on the second semiconductor layer and being narrower than the second semiconductor layer in bandgap in average.

11. The nitride semiconductor device according to claim 1 , wherein
the semiconductor stack has a first semiconductor layer and a second semiconductor layer, the first semiconductor layer is made of a nitride semiconductor provided on the base, the second semiconductor layer having a structure in which at least one layer of nitride semiconductor layer being provided at an upper layer of the first semiconductor layer and containing aluminum, the second semiconductor layer has an average Al composition ratio X and is broader than the first semiconductor layer in bandgap in average,
the second semiconductor layer is configured with layering a first nitride semiconductor layer and a second nitride semiconductor layer at least one time alternately, the first nitride semiconductor layer contains a nitride semiconductor of which maximal Al composition ratio is higher than the average Al composition ratio X, the second nitride semiconductor layer contains a nitride semiconductor of which minimal Al composition ratio is lower than the average Al composition ratio X, and
the maximal Al composition ratio of the first nitride semiconductor layer is higher than the average Al composition ratio X by a range of equal to or greater than 0.03 and smaller than 0.3.

12. The nitride semiconductor device according to claim 11 , wherein an Al composition ratio of the second semiconductor layer increases and decreases continuously so as to increase and then decrease in this order in the first nitride semiconductor layer and across the maximal Al composition ratio and decrease and then increase in this order in the second nitride semiconductor layer across the minimal Al composition ratio along a lamination direction from the primary surface of the base toward a top surface of the second semiconductor layer.

13. The nitride semiconductor device according to claim 11 , wherein the maximal Al composition ratio of the first nitride semiconductor layer is equal to or greater than 0.2 and smaller than 0.6.

14. The nitride semiconductor device according to claim 11 , wherein the minimal Al composition ratio of the second nitride semiconductor layer is lower than the average Al composition ratio X of the second semiconductor layer by a range of equal to or greater than 0.03 and smaller than 0.2.

15. The nitride semiconductor device according to claim 11 , wherein the minimal Al composition ratio of the second nitride semiconductor layer is greater than zero and smaller than 0.2.

16. The nitride semiconductor device according to claim 11 , wherein the average Al composition ratio X of the second nitride semiconductor layer is equal to or greater than 0.1 and equal to or lower than 0.4.

17. The nitride semiconductor device according to claim 11 , wherein a thickness of the second semiconductor layer is equal to or greater than 2 nm.

18. The nitride semiconductor device according to claim 11 , wherein a thickness of the second semiconductor layer is equal to or lower than 30 nm.

19. The nitride semiconductor device according to claim 11 , wh

Assignees

• Furukawa Electric Co Ltd

Inventors

• Umeno Kazuyuki
• Otomo Shinya
• Takaki Keishi
• Li Jiang
• Kokawa Takuya
• Tamura Ryosuke
• Iwami Masayuki
• Kaya Shusuke
• Ishii Hirotatsu

Classifications

• H01L29/4236

  Electricity · mapped topic

• H01L29/66212

  Electricity · mapped topic

• H01L29/0653

  Electricity · mapped topic

• H01L29/513

  Electricity · mapped topic

• H01L29/7787 Primary

  Electricity · mapped topic