SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SAME

• US 20140077263A1
• Filed: 03/05/2013
• Published: 03/20/2014
• Est. Priority Date: 09/20/2012
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: YOSHIOKA, Akira, SAITO, Yasunobu, FUJIMOTO, Hidetoshi, OHNO, Tetsuya, NAKA, Toshiyuki
• Granted Patent: US 8,963,204 B2
• Time in Patent Office: Days
• US Class Current: 257/191
• CPC Class Codes: H01L 21/02389 Nitrides
• 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 29/207 further characterised by the doping material H01L29/2006 takes precedence
• CPC Class Codes: H01L 29/417 carrying the current to be rectified, amplified or switched
• 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

According to one embodiment, a semiconductor device includes a first nitride semiconductor layer, a second nitride semiconductor layer, a third nitride semiconductor layer, an insulating film, an ohmic electrode, and a Schottky electrode. A surface region of the third nitride semiconductor layer between the ohmic electrode and the Schottky electrode contains an element heterogeneous with the constituent element of the third nitride semiconductor layer at a higher concentration than a region of the third nitride semiconductor layer of the second nitride semiconductor layer side.

Claims

1. A semiconductor device comprising:

a first nitride semiconductor layer containing a group III element;

a second nitride semiconductor layer provided on the first nitride semiconductor layer, having a larger bandgap than the first nitride semiconductor layer, and containing a group III element;

a third nitride semiconductor layer provided on the second nitride semiconductor layer and containing a group III element;

an insulating film being in contact with the third nitride semiconductor layer and provided on the third nitride semiconductor layer;

an ohmic electrode in ohmic contact with the second nitride semiconductor layer; and

a Schottky electrode in Schottky contact with the second nitride semiconductor layer,

a surface region of the third nitride semiconductor layer between the ohmic electrode and the Schottky electrode containing an element heterogeneous with the constituent element of the third nitride semiconductor layer at a higher concentration than a region of the third nitride semiconductor layer of the second nitride semiconductor layer side.

2. The device according to claim 1, wherein the heterogeneous element is boron, argon, iron, fluorine, or chlorine.

3. The device according to claim 1, wherein the region containing the heterogeneous element is provided in the surface region of the third nitride semiconductor layer and a region of the insulating film of the third nitride semiconductor layer side.

4. The device according to claim 1, wherein number of bonds between the group III element and nitrogen in the surface region of the third nitride semiconductor layer between the ohmic electrode and the Schottky electrode is smaller than number of bonds between the group III element and nitrogen in the region of the third nitride semiconductor layer of the second nitride semiconductor layer side.

5. The device according to claim 4, wherein nitrogen concentration of the surface region of the third nitride semiconductor layer is higher than nitrogen concentration of the region of the second nitride semiconductor layer side.

6. The device according to claim 1, wherein the insulating film is a silicon nitride film, silicon oxide film, or silicon oxynitride film.

7. The device according to claim 1, wherein the first nitride semiconductor layer, the second nitride semiconductor layer, and the third nitride semiconductor layer are represented by In_xAl_yGa_1-x-yN (0≦

x≦

1, 0≦

y≦

1, x+y≦

1).

8. The device according to claim 1, wherein the device is a Schottky barrier diode including an anode electrode as the Schottky electrode and a cathode electrode as the ohmic electrode.

9. The device according to claim 1, wherein the device is a Schottky gate transistor including a drain electrode and a source electrode as the ohmic electrode and a gate electrode as the Schottky electrode, the gate electrode being provided between the drain electrode and the source electrode.

10. A semiconductor device comprising:

a first nitride semiconductor layer containing a group III element;

a second nitride semiconductor layer provided on the first nitride semiconductor layer, having a larger bandgap than the first nitride semiconductor layer, and containing a group III element;

a third nitride semiconductor layer provided on the second nitride semiconductor layer and containing a group III element;

an insulating film being in contact with the third nitride semiconductor layer and provided on the third nitride semiconductor layer;

an ohmic electrode in ohmic contact with the second nitride semiconductor layer; and

a Schottky electrode in Schottky contact with the second nitride semiconductor layer,

number of bonds between the group III element and nitrogen in a surface region of the third nitride semiconductor layer between the ohmic electrode and the Schottky electrode being smaller than number of bonds between the group III element and nitrogen in a region of the third nitride semiconductor layer of the second nitride semiconductor layer side.

11. The device according to claim 10, wherein nitrogen concentration of the surface region of the third nitride semiconductor layer is higher than nitrogen concentration of the region of the second nitride semiconductor layer side.

12. The device according to claim 10, wherein the insulating film is a silicon nitride film, silicon oxide film, or silicon oxynitride film.

13. The device according to claim 10, wherein the first nitride semiconductor layer, the second nitride semiconductor layer, and the third nitride semiconductor layer are represented by In_xAl_yGa_1-x-yN (0≦

x≦

1, 0≦

y≦

1, x+y≦

1).

14. The device according to claim 10, wherein the device is a Schottky barrier diode including an anode electrode as the Schottky electrode and a cathode electrode as the ohmic electrode.

15. The device according to claim 10, wherein the device is a Schottky gate transistor including a drain electrode and a source electrode as the ohmic electrode and a gate electrode as the Schottky electrode, the gate electrode being provided between the drain electrode and the source electrode.

16. A method for manufacturing a semiconductor device, comprising:

forming a second nitride semiconductor layer containing a group III element on a first nitride semiconductor layer containing a group III element, the second nitride semiconductor layer having a larger bandgap than the first nitride semiconductor layer;

forming a third nitride semiconductor layer containing a group III element on the second nitride semiconductor layer;

forming an insulating film on the third nitride semiconductor layer, the insulating film being in contact with the third nitride semiconductor layer;

forming an ohmic electrode in ohmic contact with the second nitride semiconductor layer;

forming a Schottky electrode in Schottky contact with the second nitride semiconductor layer; and

implanting an element heterogeneous or homogeneous with the constituent element of the third nitride semiconductor layer into a surface region of the third nitride semiconductor layer by ion implantation technique.

17. The method according to claim 16, further comprising:

performing annealing after the forming the ohmic electrode,

wherein the Schottky electrode is formed after the annealing.

18. The method according to claim 16, further comprising:

performing annealing after the forming the ohmic electrode,

wherein the element is implanted into the surface region of the third nitride semiconductor layer after the annealing.

19. The method according to claim 16, wherein after the forming the insulating film on the third nitride semiconductor layer, the element is implanted into the surface region of the third nitride semiconductor layer and a region of the insulating film of the third nitride semiconductor layer side.

20. The method according to claim 16, wherein before the forming the insulating film on the third nitride semiconductor layer, the element is implanted into the surface region of the third nitride semiconductor layer.