Dual-gate trench IGBT with buried floating P-type shield

Patent metadata

Field	Value
Publication number	US-10199455-B2
Application number	US-201715600782-A
Country	US
Kind code	B2
Filing date	May 21, 2017
Priority date	Oct 31, 2010
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A method of manufacturing an insulated gate bipolar transistor (IGBT) device comprising 1) preparing a semiconductor substrate with an epitaxial layer of a first conductivity type supported on the semiconductor substrate of a second conductivity type; 2) applying a gate trench mask to open a first trench and second trench followed by forming a gate insulation layer to pad the trench and filling the trench with a polysilicon layer to form the first trench gate and the second trench gate; 3) implanting dopants of the first conductivity type to form an upper heavily doped region in the epitaxial layer; and 4) forming a planar gate on top of the first trench gate and apply implanting masks to implant body dopants and source dopants to form a body region and a source region near a top surface of the semiconductor substrate.

First claim

We claim:

1. An insulated gate bipolar transistor (IGBT) device supported in a semiconductor substrate wherein:
the semiconductor substrate comprising an epitaxial layer of a first conductivity type supported on a bottom layer of a second conductivity type electrically contacting a collector electrode disposed on a bottom surface of the semiconductor substrate;
a body region of the second conductivity type disposed near a top surface of the semiconductor substrate encompassing a source region of the first conductivity type below a top surface of the semiconductor substrate;
a first trench gate and a second trench gate disposed on two opposite sides of the body region and a planar gate disposed on the top surface of the semiconductor substrate extending laterally over the body regions disposed next to the first and second trench gates;
a third trench gate extends vertically beneath the planar gate filled with a gate material; and
the epitaxial layer further includes an upper heavily doped layer epitaxial layer surrounding and below the body regions having a higher dopant concentration of the first conductivity type than a lower epitaxial layer of the first conductivity type disposed above the bottom layer of the second conductivity type.

2. An insulated gate bipolar transistor (IGBT) device supported in a semiconductor substrate wherein:
the semiconductor substrate comprising an epitaxial layer of a first conductivity type supported on a bottom layer of a second conductivity type electrically contacting a collector electrode disposed on a bottom surface of the semiconductor substrate;
a body region of the second conductivity type disposed near a top surface of the semiconductor substrate encompassing a source region of the first conductivity type below a top surface of the semiconductor substrate;
a first trench gate and a second trench gate disposed on two opposite sides of the body region and a planar gate disposed on the top surface of the semiconductor substrate extending laterally over the body regions disposed next to the first and second trench gates;
a third trench gate extends vertically beneath the planar gate filled with a gate material; and
a plurality of floating buried ring regions of the second conductivity type disposed below a trench bottom surface of the first and second trench gates.

3. The IGBT device of claim 2 further comprising:
the floating buried ring regions extending laterally as a stripe aligned with the first and second trench gates.

4. The IGBT device of claim 2 further comprising:
the floating buried ring regions are disposed as separated buried ring regions below the trench bottom surfaces of the first and second trench gates.

5. The IGBT device of claim 1 wherein:
the epitaxial layer of the first conductivity type is an N-type epitaxial layer supported on a bottom layer of a P-type conductivity type.

6. The IGBT device of claim 5 wherein
the body region is the P-type conductivity type disposed near a top surface of the semiconductor substrate encompassing a source region of the N-type conductivity type below a top surface of the semiconductor substrate.

7. IGBT device of claim 1 further comprising:
a source/body contact region having a higher dopant concentration of the second conductivity type than the body region disposed next to the source region for contacting a source electrode.

8. The IGBT device of claim 1 wherein:
at least one of the first and second trench gate is electrically connected to a source electrode.

9. The IGBT device of claim 1 wherein:
the third trench gate is electrically connected to the planar gate.

10. The IGBT device of claim 1 wherein:
the third trench gate is insulated from the planar gate by a gate oxide.

11. The IGBT device of claim 1 wherein:
at least one of the first and second trench gate is electrically connected to a gate electrode.

12. The IGBT device of claim 1 wherein:
at least one of the first and second trench gate is electrically connected to a source electrode.

13. The IGBT device of claim 1 further comprising:
a vertical gate oxide covering and encapsulating the planar gate.

14. The IGBT device of claim 13 wherein:
the vertical gate oxide having a thickness of approximately 1000 Angstroms covering and encapsulating the planar gate.

15. The IGBT device of claim 1 further comprising:
a plurality of floating buried ring regions of the second conductivity type disposed below a trench bottom surface of the first and second trench gates.

16. The IGBT device of claim 15 wherein:
the floating buried ring regions extending laterally as a stripe aligned with the first and second trench gates.

17. The IGBT device of claim 15 wherein
the floating buried ring regions are disposed as separated buried ring regions below the trench bottom surfaces of the first and second trench gates.

18. The IGBT device of claim 2 wherein:
the epitaxial layer further includes an upper heavily doped layer epitaxial layer surrounding and below the body regions having a higher dopant concentration of the first conductivity type than a lower epitaxial layer of the first conductivity type disposed above the bottom layer of the second conductivity type.

19. The IGBT device of claim 2 wherein:
the epitaxial layer of the first conductivity type is an N-type epitaxial layer supported on a bottom layer of a P-type conductivity type.

20. The IGBT device of claim 19 wherein:
the body region is the P-type conductivity type disposed near a top surface of the semiconductor substrate encompassing a source region of the N-type conductivity type below a top surface of the semiconductor substrate.

21. The IGBT device of claim 2 further comprising:
a source/body contact region having a higher dopant concentration of the second conductivity type than the body region disposed next to the source region for contacting a source electrode.

22. The IGBT device of claim 2 wherein:
at least one of the first and second trench gate is electrically connected to a source electrode.

23. The IGBT device of claim 2 wherein:
the third trench gate is electrically connected to the planar gate.

24. The IGBT device of claim 2 wherein:
the third trench gate is insulated from the planar gate by a gate oxide.

25. The IGBT device of claim 2 wherein:
at least one of the first and second trench gate is electrically connected to a gate electrode.

26. The IGBT device of claim 2 wherein:
at least one of the first and second trench gate is electrically connected to a source electrode.

27. The IGBT device of claim 2 further comprising:
a vertical gate oxide covering and encapsulating the planar gate.

28. The IGBT device of claim 27 wherein:
the vertical gate oxide having a thickness of approximately 1000 Angstroms covering and encapsulating the planar gate.

Assignees

• Hu Jun
• Bobde Madhur
• Yilmaz Hamza
• Alpha & Omega Semiconductor

Inventors

• Hu Jun
• Bobde Madhur
• Yilmaz Hamza

Classifications

• H10P30/20

  into semiconductor materials, e.g. for doping · CPC title

• H01L29/42368

  Electricity · mapped topic

• H01L29/0696

  Electricity · mapped topic

• H01L29/42376

  Electricity · mapped topic

• H01L29/66333

  Electricity · mapped topic