Semiconductor device provided with an IE type trench IGBT

• US 9,368,595 B2
• Filed: 05/19/2015
• Issued: 06/14/2016
• Est. Priority Date: 05/22/2014
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Matsuura, Hitoshi
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US14/715,648
• Publication Number:
  US 20150340480A1
• Time in Patent Office: 392 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• 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 29/0638 for preventing surface leakage due to surface inversion layer, e.g. with channel stopper channel stoppers in combination with isolation region for integrated circuits H01L21/762
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/0804 Emitter regions of bipolar transistors
• CPC Class Codes: H01L 29/0821 Collector regions of bipolar transistors
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 29/404 Multiple field plate structures
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41708 Emitter or collector electrodes for bipolar transistors
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/42364 characterised by the insulating layer, e.g. thickness or uniformity H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66333 Vertical insulated gate bipolar transistors
• CPC Class Codes: H01L 29/66348 with a recessed gate
• CPC Class Codes: H01L 29/7393 Insulated gate bipolar mode transistors, i.e. IGBT; IGT; COMFET
• CPC Class Codes: H01L 29/7395 Vertical transistors, e.g. vertical IGBT
• 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 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A switching loss is prevented from being deteriorated by suppressing increase in a gate capacitance due to a cell shrink of an IE type trench gate IGBT. A cell formation region is configured of a linear active cell region, a linear hole collector cell region, and a linear inactive cell region between them. Then, upper surfaces of the third and fourth linear trench gate electrodes which are formed so as to sandwich both sides of the linear hole collector cell region and electrically connected to an emitter electrode are positioned to be lower than upper surfaces of the first and second linear trench gate electrodes which are formed so as to sandwich both sides of the linear active cell region and electrically connected to a gate electrode.

Claims

1. A semiconductor device provided with an IE type trench IGBT comprising:

(a) a semiconductor substrate which has a first main surface and a second main surface opposite to the first main surface;

(b) a collector region which is formed in the semiconductor substrate and which has a first conductivity type;

(c) a drift region which is formed in the semiconductor substrate on the collector region and which has a second conductivity type different from the first conductivity type;

(d) a plurality of linear unit cell regions which are formed along a first direction in the semiconductor substrate on the drift region and each of which is formed of a first linear unit cell region and a second linear unit cell region;

(e) a gate electrode provided on the first main surface side;

(f) an emitter electrode provided on the first main surface side; and

(g) a collector electrode provided on the second main surface side,

the first linear unit cell region including;

(x1) a linear active cell region provided from the first main surface to inside;

(x2) a first trench and a second trench which are formed so as to sandwich both sides of the linear active cell region in the first direction and so as to have a first depth from the first main surface;

(x3) a first linear trench gate electrode and a second linear trench gate electrode which are electrically connected to the gate electrode and which are formed inside the first trench and the second trench, respectively;

(x4) an emitter region of the second conductivity type which is formed in the linear active cell region so as to have a second depth from the first main surface;

(x5) a first body region of the first conductivity type which is formed below the emitter region of the linear active cell region so as to have a third depth deeper than the second depth from the first main surface;

(x6) a first linear inactive cell region provided on both sides of the linear active cell region in the first direction via the first trench and the second trench; and

(x7) a first floating region of the first conductivity type which is formed in the first linear inactive cell region so as to have a fourth depth from the first main surface, and

the second linear unit cell region including;

(y1) a linear hole collector cell region provided from the first main surface to inside;

(y2) a third trench and a fourth trench which are formed so as to sandwich both sides of the linear hole collector cell region in the first direction and so as to have the first depth from the first main surface;

(y3) a third linear trench gate electrode and a fourth linear trench gate electrode which are electrically connected to the emitter electrode and which are formed inside the third trench and the fourth trench, respectively;

(y4) a second body region of the first conductivity type which is formed in the linear hole collector cell region so as to have the third depth from the first main surface;

(y5) a second linear inactive cell region provided on both sides of the linear hole collector cell region in the first direction via the third trench and the fourth trench; and

(y6) a second floating region of the first conductivity type which is formed in the second linear inactive cell region so as to have the fourth depth from the first main surface,

wherein, further, upper surfaces of the third linear trench gate electrode and the fourth linear trench gate electrode are positioned to be lower than upper surfaces of the first linear trench gate electrode and the second linear trench gate electrode.

2. The semiconductor device according to claim 1,

wherein upper surfaces of the third linear trench gate electrode and the fourth linear trench gate electrode are positioned to be lower than the third depth of the second body region.

3. The semiconductor device according to claim 1,

wherein the first linear unit cell region further includes a first gate insulation film formed in inner walls of the first trench and the second trench,

a thickness of the first gate insulation film on the first linear inactive cell region side is thicker than a thickness of the first gate insulation film on the linear active cell region side,

the second linear unit cell region further includes a second gate insulation film formed in inner walls of the third trench and the fourth trench, and

a thickness of the second gate insulation film on the second linear inactive cell region side is thicker than a thickness of the second gate insulation film on the linear hole collector cell region side.

4. The semiconductor device according to claim 1,

wherein the first linear unit cell region further includes a first hole barrier region of the second conductivity type formed below the first body region in the linear active cell region, and

an impurity concentration of the first hole barrier region is higher than an impurity concentration of the drift region and lower than an impurity concentration of the emitter region.

5. The semiconductor device according to claim 4,

wherein the second linear unit cell region further includes

a second hole barrier region of the second conductivity type formed below the second body region in the linear hole collector cell region.

6. The semiconductor device according to claim 5,

wherein the second linear unit cell region further includes

a connection region of the second conductivity type which is formed below the second hole barrier region in the linear hole collector cell region and which is connected to the second linear inactive cell region provided on both sides of the linear hole collector cell region in the first direction.

7. The semiconductor device according to claim 1,

wherein the first linear unit cell region further includes:

a first linear dummy trench gate electrode formed below the first linear trench gate electrode via a first insulation film in the first trench; and

a second linear dummy trench gate electrode formed below the second linear trench gate electrode via a second insulation film in the second trench.

8. The semiconductor device according to claim 7,

wherein a thickness of a first gate insulation film formed between the first linear trench gate electrode and an inner wall of the first trench is thinner than a thickness of a first dummy insulation film formed between the first linear dummy trench gate electrode and an inner wall of the first trench, and

a thickness of a second gate insulation film formed between the second linear trench gate electrode and an inner wall of the second trench is thinner than a thickness of a second dummy insulation film formed between the second linear dummy trench gate electrode and an inner wall of the second trench.

9. The semiconductor device according to claim 7,

wherein the second linear unit cell region further includes:

a third linear dummy trench gate electrode formed below the third linear trench gate electrode via a third insulation film in the third trench; and

a fourth linear dummy trench gate electrode formed below the fourth linear trench gate electrode via a fourth insulation film in the fourth trench.

10. The semiconductor device according to claim 9,

wherein a thickness of a third gate insulation film formed between the third linear trench gate electrode and an inner wall of the third trench is thinner than a thickness of a third dummy insulation film formed between the third linear dummy trench gate electrode and an inner wall of the third trench, and

a thickness of a fourth gate insulation film formed between the fourth linear trench gate electrode and an inner wall of the fourth trench is thinner than a thickness of a fourth dummy insulation film formed between the fourth linear dummy trench gate electrode and an inner wall of the fourth trench.

11. The semiconductor device according to claim 1,

wherein the fourth depth of the first floating region is deeper than the first depth of the first trench and the second trench.

12. A semiconductor device provided with an IE type trench IGBT comprising:

(a) a semiconductor substrate which has a first main surface and a second main surface opposite to the first main surface;

(b) a collector region which is formed in the semiconductor substrate and which has a first conductivity type;

(c) a drift region which is formed in the semiconductor substrate on the collector region and which has a second conductivity type different from the first conductivity type;

(d) a plurality of linear unit cell regions which are formed along a first direction in the semiconductor substrate on the drift region;

(e) a gate electrode provided on the first main surface side;

(f) an emitter electrode provided on the first main surface side; and

(g) a collector electrode provided on the second main surface side,

the linear unit cell region including;

(d1) a linear hybrid cell region provided from the first main surface to inside;

(d2) a first linear hybrid sub cell region and a second linear hybrid sub cell region provided in the linear hybrid cell region so as to be symmetrical to each other in the first direction;

(d3) a first trench formed at a boundary between the first linear hybrid sub cell region and the second linear hybrid sub cell region so as to have a first depth from the first main surface;

(d4) a first linear trench gate electrode which is electrically connected to the gate electrode and which is formed inside the first trench;

(d5) a second trench and a third trench which are formed so as to sandwich both sides of the linear hybrid cell region in the first direction and so as to have the first depth from the first main surface;

(d6) a second linear trench gate electrode and a third linear trench gate electrode which are electrically connected to the emitter electrode and which are formed inside the second trench and the third trench, respectively;

(d7) an emitter region of the second conductivity type which is formed so as to have a second depth from the first main surface and so as to be in contact with the first trench in a central part of the linear hybrid cell region;

(d8) a body region of the first conductivity type which is formed below the emitter region so as to have a third depth deeper than the second depth from the first main surface;

(d9) a linear inactive cell region provided on both sides of the linear hybrid cell region in the first direction via the second trench and the third trench; and

(d10) a floating region of the first conductivity type which is formed in the linear inactive cell region so as to have a fourth depth from the first main surface,

wherein, further, upper surfaces of the second linear trench gate electrode and the third linear trench gate electrode are positioned to be lower than an upper surface of the first linear trench gate electrode.

13. The semiconductor device according to claim 12,

wherein upper surfaces of the second linear trench gate electrode and the third linear trench gate electrode are positioned to be lower than the third depth of the body region.

14. The semiconductor device according to claim 12,

wherein the linear hybrid cell region further includes

a hole barrier region of the second conductivity type formed below the body region in the first linear hybrid sub cell region and the second linear hybrid sub cell region, and

an impurity concentration of the hole barrier region is higher than an impurity concentration of the drift region and lower than an impurity concentration of the emitter region.

15. The semiconductor device according to claim 12,

wherein the fourth depth of the floating region is deeper than the first depth of the first trench and the second trench.

16. A semiconductor device provided with an IE type trench IGBT comprising:

(a) a semiconductor substrate which has a first main surface and a second main surface opposite to the first main surface;

(b) a collector region which is formed in the semiconductor substrate and which has a first conductivity type;

(c) a drift region which is formed in the semiconductor substrate on the collector region and which has a second conductivity type different from the first conductivity type;

(d) a plurality of linear unit cell regions which are formed along a first direction in the semiconductor substrate on the drift region and each of which is formed of a first linear unit cell region and a second linear unit cell region;

(e) a gate electrode provided on the first main surface side;

(f) an emitter electrode provided on the first main surface side; and

(g) a collector electrode provided on the second main surface side,

the first linear unit cell region including;

(x1) a linear active cell region provided from the first main surface to inside;

(x2) a first trench and a second trench which are formed so as to sandwich both sides of the linear active cell region in the first direction and so as to have a first depth from the first main surface;

(x3) a first linear trench gate electrode and a second linear trench gate electrode which are electrically connected to the gate electrode and which are formed inside the first trench and the second trench, respectively;

(x4) an emitter region of the second conductivity type which is formed in the linear active cell region so as to have a second depth from the first main surface;

(x5) a first body region of the first conductivity type which is formed below the emitter region of the linear active cell region so as to have a third depth deeper than the second depth from the first main surface;

(x6) a first linear inactive cell region provided on both sides of the linear active cell region in the first direction via the first trench and the second trench;

(x7) a first floating region of the first conductivity type which is formed in the first linear inactive cell region so as to have a fourth depth from the first main surface; and

(x8) a first contact groove which is formed in the linear active cell region so as to have a width smaller than a gap between the first trench and the second trench and so as to have a fifth depth shallower than the third depth from the first main surface and in which the emitter electrode is embedded, and

the second linear unit cell region including;

(y1) a linear hole collector cell region provided from the first main surface to inside;

(y2) a third trench and a fourth trench which are formed so as to sandwich both sides of the linear hole collector cell region in the first direction and so as to have the first depth from the first main surface;

(y3) a third linear trench gate electrode and a fourth linear trench gate electrode which are electrically connected to the emitter electrode and which are formed inside the third trench and the fourth trench, respectively;

(y4) a second linear inactive cell region provided on both sides of the linear hole collector cell region in the first direction via the third trench and the fourth trench;

(y5) a second floating region of the first conductivity type which is formed in the second linear inactive cell region so as to have the fourth depth from the first main surface; and

(y6) a second contact groove which is formed in the linear hole collector cell region so as to have the fifth depth from the first main surface and in which the emitter electrode is embedded,

wherein, further, upper surfaces of the third linear trench gate electrode and the fourth linear trench gate electrode are positioned to be lower than upper surfaces of the first linear trench gate electrode and the second linear trench gate electrode, and

a width of the first contact groove in the first direction and a width of the second contact groove in the first direction are different from each other.

17. The semiconductor device according to claim 16,

wherein a width of the second contact groove in the first direction is larger than a width of the first contact groove in the first direction.

18. The semiconductor device according to claim 16,

wherein a gap between the third trench and the fourth trench is narrower than a gap between the first trench and the second trench.

19. The semiconductor device according to claim 16,

wherein a width of the second contact groove in the first direction is larger than a width of the first contact groove in the first direction, and a gap between the third trench and the fourth trench is narrower than a gap between the first trench and the second trench.

20. The semiconductor device according to claim 16,

wherein the second contact groove overlaps with the third trench or the fourth trench, or the third trench and the fourth trench, when seen in a plan view.