Shielded gate trench FET with multiple channels

• US 9,224,853 B2
• Filed: 07/19/2012
• Issued: 12/29/2015
• Est. Priority Date: 12/26/2007
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Pan, James
• Primary Examiner(s): Sengdara, Vongsavanh
• Application Number:
  US13/553,285
• Publication Number:
  US 20120280312A1
• Time in Patent Office: 1,258 Days
• Field of Search: 257/330, 257/409, 257/E21.417, 257/E29.257, 438/270
• US Class Current: 1/1
• CPC Class Codes: H01L 29/0623 Buried supplementary region, e.g. buried guard ring multi-RESURF H01L29/0634
• 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 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• 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 29/7831 with multiple gate structure FinFETs or MuGFETs H01L29/7855, thin film transistors H01L29/78645

Abstract

In one embodiment, an apparatus can include a trench extending into a semiconductor region of a first conductivity type, an electrode disposed in the trench, and a source region of the first conductivity type abutting a sidewall of the trench. The apparatus can include a first well region of a second conductivity type disposed in the semiconductor region below the source region and abutting the sidewall of the trench lateral to the electrode where the second conductivity type is opposite the first conductivity type. The apparatus can also include a second well region of the second conductivity type disposed in the semiconductor region and abutting the sidewall of the trench, and a third well region of the first conductivity type disposed between the first well region and the second well region.

Claims

1. A semiconductor device, comprising:

a pair of trenches extending into a semiconductor region of a first conductivity type;

a shield electrode disposed in a trench from the pair of trenches;

a gate electrode disposed in the trench from the pair of trenches and above the shield electrode, the gate electrode being insulated from the shield electrode;

a source region of the first conductivity type associated with the trench from the pair of trenches;

a first well region of a second conductivity type disposed in the semiconductor region between the pair of trenches, a portion of the first well region being disposed below the source region, the first well region directly contacting a sidewall of the trench from the pair of trenches, the second conductivity type being opposite the first conductivity type;

a second well region of the second conductivity type disposed in the semiconductor region between the pair of trenches, the second well region directly contacting the sidewall of the trench from the pair of trenches; and

a third well region of the first conductivity type disposed between the pair of trenches and between the first well region and the second well region, the third well region directly contacting the sidewall of the trench from the pair of trenches, the third well region being disposed below and in direct contact with the first well region, the third well region being disposed above and in direct contact with the second well region.

2. The semiconductor device of claim 1, wherein the first well region, the second well region, and the third well region are associated with the shield electrode.

3. The semiconductor device of claim 1, wherein the first well region, the second well region, and the third well region are disposed lateral to the shield electrode.

4. The semiconductor device of claim 1, wherein the shield electrode is formed relative to the first well region and the second well region such that a channel is formed in each of the first well region and the second well region when a voltage is applied to the shield electrode.

5. The semiconductor device of claim 1, wherein the shield electrode is a first shield electrode,

the semiconductor device further comprising:

a second shield electrode electrically insulated from the first shield electrode.

6. The semiconductor device of claim 1, wherein the shield electrode is a first shield electrode, the first well region, the second well region, and the third well region are disposed lateral to the first shield electrode,

the semiconductor device further comprising:

a second shield electrode electrically insulated from the first shield electrode.

7. The semiconductor device of claim 1, wherein the shield electrode is a first shield electrode,

the semiconductor device further comprising:

a second shield electrode; and

a dielectric disposed in the trench between the first shield electrode and the second shield electrode, the second shield electrode being electrically coupled to the first shield electrode.

8. A semiconductor device, comprising:

a trench extending into a semiconductor region of a first conductivity type;

an electrode disposed in the trench;

a source region of the first conductivity type abutting a sidewall of the trench;

a first well region of a second conductivity type disposed in the semiconductor region, a portion of the first well region being disposed below the source region and in direct contact with the sidewall of the trench lateral to the electrode, the second conductivity type being opposite the first conductivity type;

a second well region of the second conductivity type disposed in the semiconductor region and in direct contact with the sidewall of the trench; and

a third well region of the first conductivity type disposed in the semiconductor region and disposed between the first well region and the second well region, the third well region being in direct contact with the sidewall of the trench, the third well region being disposed below and in direct contact with the first well region, the third well region being disposed above and in direct contact with the second well region.

9. The semiconductor device of claim 8, wherein the first well region, the second well region, and the third well region are associated with the electrode.

10. The semiconductor device of claim 8, wherein the electrode is a shield electrode, the shield electrode is formed relative to the first well region and the second well region such that a channel is formed in each of the first well region and the second well region when a voltage is applied to the shield electrode.

11. The semiconductor device of claim 8, wherein the electrode is a shield electrode,

the semiconductor device further comprising:

a gate electrode disposed in the trench and above the shield electrode, the gate electrode being insulated from at least a portion of the shield electrode; and

a fourth well region disposed between the first well region and the second well region, the fourth well region being disposed lateral to the gate electrode.

12. The semiconductor device of claim 8, wherein the electrode is a gate electrode,

the semiconductor device further comprising:

a shield electrode disposed in the trench and below the gate electrode, the shield electrode being insulated from at least a portion of the gate electrode, the second well region being disposed lateral to the shield electrode.

13. The semiconductor device of claim 8, wherein the electrode is a first shield electrode,

the semiconductor device further comprising:

a second shield electrode electrically insulated from the first shield electrode.

14. The semiconductor device of claim 8, wherein the electrode is a first shield electrode, the first well region, the second well region, and the third well region are disposed lateral to the first shield electrode,

the semiconductor device further comprising:

a second shield electrode electrically insulated from the first shield electrode.

15. The semiconductor device of claim 8, wherein the electrode is a first shield electrode,

the semiconductor device further comprising:

a second shield electrode; and

a dielectric disposed in the trench between the first shield electrode and the second shield electrode, the second shield electrode being electrically coupled to the first shield electrode.

16. A semiconductor device, comprising:

a trench extending into a semiconductor region of a first conductivity type;

a shield electrode disposed in the trench;

a gate electrode disposed in the trench and above the shield electrode, the gate electrode being insulated from the shield electrode;

a source region of the first conductivity type abutting a sidewall of the trench;

a first well region of a second conductivity type disposed in the semiconductor region, a portion of the first well region being disposed below the source region and in direct contact with the sidewall of the trench, the second conductivity type being opposite the first conductivity type;

a second well region of the second conductivity type disposed in the semiconductor region and in direct contact with the sidewall of the trench; and

a third well region of the first conductivity type disposed in the semiconductor region and between the first well region and the second well region, the third well region in direct contact with the sidewall of the trench, the third well region being disposed below and in direct contact with the first well region, the third well region being disposed above and in direct contact with the second well region.

17. The semiconductor device of claim 16, wherein the first well region, the second well region, and the third well region are disposed lateral to the shield electrode.

18. The semiconductor device of claim 16, wherein the shield electrode is formed relative to the first well region and the second well region such that a channel is formed in each of the first well region and the second well region when a voltage is applied to the shield electrode.

19. The semiconductor device of claim 16, further comprising:

a heavily-doped body region of the second conductivity type in contact with the source region.

20. The semiconductor device of claim 16, wherein the gate electrode and the shield electrode are positioned relative to the first well region and the second well region such that a channel is formed in each of the first well region and the second well region when the semiconductor device is biased in the on state.