Semiconductor device

• US 9,190,507 B2
• Filed: 12/05/2012
• Issued: 11/17/2015
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Imada, Tadahiro
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): Nguyen, Lawrence-Linh T
• Application Number:
  US13/705,548
• Publication Number:
  US 20130092952A1
• Time in Patent Office: 1,077 Days
• Field of Search: 257/76, 257/133, 257/E29.242
• US Class Current: 1/1
• CPC Class Codes: H01L 27/0207 Geometrical layout of the components, e.g. computer aided design; custom LSI, semi-custom LSI, standard cell technique
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 27/085 including field-effect components only
• 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 29/41758 for lateral devices with structured layout for source or drain region, i.e. the source or drain region having cellular, interdigitated or ring structure or being curved or angular H01L29/41733 - H01L29/4175 take precedence
• 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
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A transistor which includes an electron transit layer and an electron supply layer which are stacked in a thickness direction of a substrate; an electron transit layer formed over the substrate in parallel to the electron transit layer and the electron supply layer; an anode electrode which forms a Schottky junction with the electron transit layer; and a cathode electrode which forms an ohmic junction with the electron transit layer are provided. The anode electrode is connected to a source of the transistor, and the cathode electrode is connected to a drain of the transistor.

Claims

1. A semiconductor device, comprising:

a substrate;

a transistor that comprises a first electron transit layer and an electron supply layer which are stacked in a thickness direction of the substrate;

a second electron transit layer formed over the substrate in parallel to the first electron transit layer and the electron supply layer;

an insulating layer that insulates the transistor and the second electron transit layer from each other, the insulating layer being between the first electron transit layer and the second electron transit layer in the thickness direction of the substrate;

an anode electrode that forms a Schottky junction with the second electron transit layer; and

a cathode electrode that forms an ohmic junction with the second electron transit layer, wherein

the anode electrode is connected to a source of the transistor, and

the cathode electrode is connected to a drain of the transistor.

2. The semiconductor device according to claim 1, wherein the transistor comprises an n-type gallium nitride layer formed over the electron supply layer.

3. The semiconductor device according to claim 2, wherein the transistor comprises:

a second insulating layer formed on the n-type gallium nitride layer and made of an aluminum nitride or an aluminum gallium nitride; and

a second n-type gallium nitride layer formed on the second insulating layer.

4. The semiconductor device according to claim 1, wherein the second electron transit layer is located between the substrate and the transistor.

5. The semiconductor device according to claim 1, wherein the second electron transit layer contains a p-type or n-type semiconductor.

6. The semiconductor device according to claim 1, wherein the second electron transit layer contains at least two types of semiconductors which have different lattice constants from each other.

7. The semiconductor device according to claim 1, wherein the second electron transit layer contains a gallium nitride or an aluminum gallium nitride.

8. The semiconductor device according to claim 1, wherein the insulating layer contains at least one selected from the group consisting of aluminum nitride, aluminum gallium nitride, p-type gallium nitride, iron doped gallium nitride, silicon oxide, aluminum oxide, silicon nitride, aluminum oxide, silicon nitride, and carbon.

9. The semiconductor device according to claim 1, wherein the anode electrode contains at least one selected from the group consisting of nickel, palladium, and platinum.

10. A semiconductor device, comprising:

a substrate;

a buffer layer formed over the substrate;

a second electron transit layer formed over the buffer layer;

an insulating layer formed over the second electron transit layer;

a first electron transit layer formed over the insulating layer;

an electron supply layer formed over the first electron transit layer; and

a cap layer formed over the electron supply layer.

11. The semiconductor device according to claim 10, wherein

an opening for a source electrode and an anode electrode that reaches the second electron transit layer is formed in the cap layer, the electron supply layer, the first electron transit layer, and the insulating layer,

an opening for a drain electrode and a cathode electrode that reaches the second electron transit layer is formed in the cap layer, the electron supply layer, the first electron transit layer, and the insulating layer,

an anode electrode that forms a Schottky junction with the second electron transit layer is formed in the opening for a source electrode and an anode electrode,

a cathode electrode which forms an ohmic junction with the second electron transit layer is formed in the opening for a drain electrode and a cathode electrode,

the anode electrode is connected to the electron supply layer;

the cathode electrode is connected to the electron supply layer, and

a gate electrode is formed over the electron supply layer between the anode electrode and the cathode electrode.

12. The semiconductor device according to claim 10, further comprising an n-type gallium nitride layer formed over the electron supply layer.

13. The semiconductor device according to claim 12, further comprising:

a second insulating layer formed over the n-type gallium nitride layer and made of an aluminum nitride or an aluminum gallium nitride; and

a second n-type gallium nitride layer formed on the second insulating layer.