Method of manufacturing a semiconductor device comprising first and second field stop zone portions

Patent metadata

Field	Value
Publication number	US-11081544-B2
Application number	US-201816202752-A
Country	US
Kind code	B2
Filing date	Nov 28, 2018
Priority date	Nov 29, 2017
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A method of manufacturing a device in a semiconductor body includes forming a first field stop zone portion of a first conductivity type and a drift zone of the first conductivity type on the first field stop zone portion. An average doping concentration of the drift zone is smaller than 80% of that of the first field stop zone portion. The semiconductor body is processed at a first surface and thinned by removing material from a second surface. A second field stop zone portion of the first conductivity type is formed by implanting protons at one or more energies through the second surface. A deepest end-of-range peak of the protons is set in the first field stop zone portion at a vertical distance to a transition between the drift zone and first field stop zone portion in a range from 3 μm to 60 μm. The semiconductor body is annealed.

First claim

What is claimed is:

1. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising:
forming a first field stop zone portion of a first conductivity type on a semiconductor substrate;
forming a drift zone of the first conductivity type on the first field stop zone portion, wherein an average doping concentration of the drift zone is set smaller than 80 % of an average doping concentration of the first field stop zone portion;
processing the semiconductor body at a first surface of the semiconductor body;
thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface;
forming a second field stop zone portion of the first conductivity type by implanting protons at one or more energies into the semiconductor body through the second surface, wherein a deepest end-of-range peak of the protons is set in the first field stop zone portion at a vertical distance to a transition between the drift zone and the first field stop zone portion in a range from 3 μm to 60 μm; and
annealing the semiconductor body by thermal processing,
wherein the protons of the second field stop zone portion are implanted at at least three different ion implantation energies.

2. The method of claim 1 , wherein the thinning of the semiconductor body is terminated at a vertical distance to the transition between the drift zone and the first field stop zone portion in a range from 5 μm to 70 μm.

3. The method of claim 1 , wherein the first field stop zone portion and the drift zone are formed by an epitaxial layer formation process.

4. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising:
forming a drift zone of a first conductivity type on a semiconductor substrate;
processing the semiconductor body at a first surface of the semiconductor body;
thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface;
forming a first field stop zone portion of the first conductivity type between the second surface and the drift zone by implanting protons into the semiconductor body through the second surface and setting a vertical distance between an end-of-range peak of the protons and the second surface in a range from 5 μm to 70 μm, and further setting an average doping concentration of the first field stop zone portion greater than 120% of an average doping concentration of the drift zone;
forming a second field stop zone portion of the first conductivity type by implanting protons at one or more energies into the semiconductor body through the second surface, wherein a deepest end-of-range peak of the protons is set in the first field stop zone portion at a vertical distance to a transition between the drift zone and the first field stop zone portion in a range from 3 μm to 60 μm; and
annealing the semiconductor body by thermal processing
wherein q 1 equals an integral of an ionized dopant charge along a vertical extension of the first field stop zone portion and q 2 equals an integral of an ionized dopant charge along a vertical extension of the second field stop zone portion, and wherein a doping concentration profile of the first and second field stop zone portions is adjusted to set a ratio of q 2 to q 1 in a range from 1 to 8.

5. The method of claim 4 , wherein a ratio of an ion implantation energy of the protons of the first field stop zone portion to an ion implantation energy of the protons associated with the deepest end-of-range peak of the second field stop zone portion is set in a range from 2 to 50.

6. The method of claim 4 , wherein a vertical extension of the second field stop zone portion is set in a range from 1 μm to 15 μm.

7. The method of claim 4 , wherein the protons of the second field stop zone portion are implanted at three to ten different ion implantation energies ranging from 200 keV to 700 keV.

8. The method of claim 7 , wherein a ratio of a smallest ion implantation energy to a largest ion implantation energy among the three to ten different ion implantation energies is set in a range from 50% to 90%.

9. The method of claim 7 , wherein an ion implantation dose of proton implantation is set smaller with increasing ion implantation energy among the three to ten different ion implantation energies.

10. The method of claim 7 , wherein an ion implantation dose associated with one of the three to ten different ion implantation energies is set between 3% and 70% of an ion implantation dose associated with another one of the three to ten different implantation energies that is a next larger ion implantation energy to the one of the three to ten different ion implantation energies.

11. The method of claim 4 , wherein annealing temperatures of the thermal processing are set in a range from 360° C. to 440° C. and a duration of the thermal processing is set in a range from 30 minutes to 2 hours.

12. The method of claim 4 , wherein an implantation dose of the protons of the second field stop zone portion is set in a range from 1×10 13 cm −2 to 5×10 15 cm −2 .

13. The method of claim 4 , wherein a doping concentration of the drift zone is set in a range from 5×10 12 cm −3 to 5×10 14 cm −3 .

14. The method of claim 4 , wherein a gradient of a dopant concentration profile of the second field stop zone portion is set smaller than 1×10 21 cm −4 .

15. The method of claim 4 , wherein q 1 is set smaller than a breakdown charge of the semiconductor body.

16. The method of claim 4 , wherein q 1 is set smaller than 60% of a breakdown charge of the semiconductor body.

17. The method of claim 4 , wherein the semiconductor device is a diode, and wherein processing the semiconductor body at the first surface comprises forming a p-doped anode region in the semiconductor body at the first surface.

18. The method of claim 4 , wherein the semiconductor device is a transistor, and wherein processing the semiconductor body at the first surface comprises forming a source region and a gate electrode structure at the first surface.

19. The method of claim 4 , wherein a doping concentration profile of the second field stop zone portion includes a plurality of peaks, and wherein the doping concentration profile is set to decrease, along a vertical direction toward the second surface, from a maximum to a neighboring minimum by less than 50% of a concentration value at the maximum.

20. The method of claim 4 , further comprising introducing dopants of the first conductivity type into the semiconductor body through the second surface, wherein the dopants are deep-level dopants.

21. A method of manufacturing a semiconductor device in a semiconductor body, the method comprising:
forming a first field stop zone portion of a first conductivity type on a semiconductor substrate;
forming a drift zone of the first conductivity type on the first field stop zone portion, wherein an average doping concentration of the drift zone is set smaller than 80% of an average doping concentration of the first field stop zone portion;
processing the semiconductor body at a first surface of the semiconductor body;
thinning the semiconductor body by removing material of the semiconductor substrate from a second surface of the semiconductor body opposite to the first surface;
forming a second field stop zone portion of the first conductivity type by introducing dopants of the firs

Assignees

• Infineon Technologies Ag

Inventors

• Schulze Hans-Joachim
• Niedernostheide Franz-Josef
• Spulber Oana Julia
• Voss Stephan

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P30/204

  into Group IV semiconductors · CPC title

• H10P30/21

  of electrically active species · CPC title

• H10P95/902

  for the formation of PN junctions without addition of impurities · CPC title

• H10D12/031

  of IGBTs · CPC title