Diode device and transistor device

• US 20030160262A1
• Filed: 02/20/2003
• Published: 08/28/2003
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: Shindengen Electric Manufacturing Company Limited
• Original Assignee: Shindengen Electric Manufacturing Company Limited
• Inventors: Kunori, Shinji, Kitada, Mizue, Kurosaki, Toru, Ohsima, Kosuke
• Granted Patent: US 7,135,718 B2
• Time in Patent Office: Days
• US Class Current: 257/127
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/0692 Surface layout
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A semiconductor device having improved breakdown voltage is provided. A diode device of the present invention includes relay diffusion layers provided between guard ring portions. Therefore, a depletion layer expanded outward from the guard ring portions except the outermost one reaches these relay diffusion layers, and then the outer guard ring portions. The width of the distance between the guard ring portions is shorter where the relay diffusion layers are provided. For the width of the relay diffusion layers, the depletion layer reaches the outer guard ring portions with a lower voltage than the conventional structure.

Claims

1. A diode device, comprising:

a semiconductor layer of a first conductivity type having a plurality of holes, said holes including ring-shaped holes and main holes provided in an inner circumference of the ring-shaped holes;

a filler made of a semiconductor of a second conductivity type filled within said holes; and

an electrode film of a material forming a Schottky junction with said semiconductor layer and an ohmic junction with said filler, wherein

among said ring-shaped holes, concentrically provided ring-shaped holes and the filler filled within these holes form a plurality of guard ring portions,

the main holes provided in the inner circumference of the innermost ring-shaped holes and the filler filled within these main holes form withstanding voltage portions,

said electrode film is at least in contact with a surface of the semiconductor layer positioned in the inner circumference of the ring of the innermost guard ring portion and a surface of the filler in the withstanding voltage portions, and

a relay diffusion layer of second conductivity type in a depth shallower than a bottom of the ring-shaped holes formed at the surface within the semiconductor layer positioned between said guard ring portions, said relay diffusion layer is not in contact with at least one of the two guard ring portions adjacent to each other.

2. The diode device according to claim 1, wherein

said relay diffusion layer in a width-wise direction of the ring of said guard ring portion is shorter than a distance between said guard ring portions adjacent to each other.

3. The diode device according to claim 1, wherein

said electrode film is provided in contact with an innermost guard ring portion among said guard ring portions.

4. The diode device according to claim 1, wherein

said electrode film is kept from contacting an innermost guard ring portion among said guard ring portions.

5. The diode device according to claim 1, wherein

said relay diffusion layer is provided in contact with one of the inner circumference and the outer circumference of the ring of said guard ring portion.

6. The diode device according to claim 1, wherein

said relay diffusion layer is kept from contacting said guard ring portions.

7. The diode device according to claim 1, wherein

said ring-shaped holes include other concentric holes other than those comprising said guard ring portions and positioned between an innermost guard ring portion among said guard ring portions and said withstanding voltage portions,

said other concentric hole and a filler filling within the other concentric hole form an intermediate ring portion, and

an insulating film is provided between the electrode film and the semiconductor layer positioned between said two intermediate ring portions adjacent to each other.

8. The diode device according to claim 7, wherein

said electrode film has its end extended at least to lie over said innermost guard ring portion.

9. A transistor device, comprising:

a semiconductor layer of a first conductivity type having a plurality of ring-shaped holes provided concentrically at one surface of said semiconductor layer and filled with a semiconductor filler of a second conductivity type;

a base region of the second conductivity type provided in the vicinity of said one surface in said semiconductor layer and in an inner circumferential region of an innermost ring-shaped hole among the plurality of ring-shaped holes;

a source region of the first conductivity type provided in said base region;

a gate insulating film provided in contact with said base region; and

a gate electrode provided in contact with said gate insulating film, wherein

said plurality of ring-shaped holes and said semiconductor filler of the second conductivity type filling said ring-shaped holes form a plurality of guard ring portions,

each of said guard ring portions is kept from contacting said base region, and

a relay diffusion layer of the second conductivity type in a depth shallower than a bottom of said ring-shaped hole is provided between said ring-shaped holes adjacent to each other and at the surface within said semiconductor layer, and kept from contacting at least one of said ring-shaped holes adjacent to each other.

10. The transistor device according to claim 9, wherein

said relay diffusion layer is provided between said innermost ring-shaped hole and said base region and kept from contacting at least one of said innermost ring-shaped hole and said base region.

11. The transistor device according to claim 9, further comprising,

an ohmic layer of the same conductivity type as that of said semiconductor layer and having a higher concentration than that of said semiconductor layer provided at a surface of said semiconductor layer opposite to the surface provided with said base region, and

a drain electrode film forming an ohmic junction with said ohmic layer provided at a surface of said ohmic layer.

12. The transistor device according to claim 9, further comprising,

a collector layer of a conductivity type different from that of said semiconductor layer provided at a surface of said semiconductor layer opposite to the surface provided with said base region, and

a collector electrode film forming an ohmic junction with said collector layer provided at a surface of said collector layer.

13. The transistor device according to claim 9, further comprising,

a Schottky electrode film forming a Schottky junction with said semiconductor layer provided at a surface of said semiconductor layer opposite to the surface provided with said base region, said Schottky junction being forward biased with a voltage of a polarity that reverse biases a PN junction formed between said semiconductor layer and said base region.