Production method for a semiconductor device

1. A method for producing a semiconductor device, comprising:

providing a semiconductor substrate having a first conductivity type;

implanting protons through a rear surface of the semiconductor substrate of the first conductivity type; and

introducing hydrogen to form a first semiconductor region of the first conductivity type in the semiconductor substrate by performing an annealing process in an annealing furnace in a hydrogen atmosphere having a volume concentration of hydrogen that is equal to or greater than 0.5% and less than 4.65% so that the first semiconductor region has a higher impurity concentration than that of the semiconductor substrate after the implantation step.

2. The method for producing a semiconductor device according to claim 1 , wherein the semiconductor device is a diode, the first semiconductor region of the first conductivity type is an n-type field stop layer, and the semiconductor substrate is a drift layer.

3. The method for producing a semiconductor device according to claim 1 , wherein the semiconductor device is an insulated gate bipolar transistor, the first semiconductor region of the first conductivity type is an n-type field stop layer, and the semiconductor substrate is a drift layer.

4. The method for producing a semiconductor device according to claim 2 , wherein the volume concentration of the hydrogen is set such that carrier concentration of a region from the n-type field stop layer of the semiconductor substrate to a cathode electrode is about that of substrate concentration.

5. The method for producing a semiconductor device according to claim 3 , wherein the volume concentration of the hydrogen is set such that carrier concentration of a region from the n-type field stop layer of the semiconductor substrate to a collector electrode is about that of substrate concentration.

6. The method for producing a semiconductor device according to claim 1 , wherein the annealing process has an annealing temperature that ranges from 300° C. to 450° C.

7. The method for producing a semiconductor device according to claim 1 , wherein the annealing process has an annealing temperature that ranges from higher than 340° C. to equal to or lower than 400° C.

8. The method for producing a semiconductor device according to claim 1 , wherein the annealing process is conducted for a processing time that ranges from 1 hour to 10 hours.

9. The method for producing a semiconductor device according to claim 8 , wherein the processing time of the annealing process ranges from 3 hours to 7 hours.

10. The method for producing a semiconductor device according to claim 8 , wherein the processing time of the annealing process is 5 hours or more.

11. The method for producing a semiconductor device according to claim 1 , wherein implanting protons is conducted with a proton dose ranging from 3×10 12 /cm 2 to 5×10 14 /cm 2 .

12. The method for producing a semiconductor device according to claim 11 , wherein the proton dose ranges from 1×10 13 /cm 2 to 1×10 14 /cm 2 .

13. The method for producing a semiconductor device according to claim 1 , wherein protons during proton implanting have an implantation energy E and a range R p , and, when a logarithm log(E) of implantation energy E of the protons is y and a logarithm log(Rp) of the range Rp of the protons is x, a relationship as follows is satisfied:

y=− 0.0047 x 4 +0.0528 x 3 −0.2211 x 2 +0.9923 x+ 5.0474.

14. The method for producing a semiconductor device according to claim 1 , wherein, during forming, the hydrogen has a volume concentration that is equal to or greater than 1.0% and equal to or less than 4.0%.

15. The method for producing a semiconductor device according to claim 2 , wherein the hydrogen has a volume concentration that is set such that carrier concentration of a region from the n-type field stop layer of the semiconductor substrate to a cathode electrode is equal to or higher than that of substrate concentration.

16. The method for producing a semiconductor device according to claim 3 , wherein the hydrogen has a volume concentration that is set such that carrier concentration of a region from the n-type field stop layer of the semiconductor substrate to a collector electrode is equal to or higher than that of substrate concentration.

17. The method for producing a semiconductor device according to claim 1 , further comprising grinding the rear surface of the semiconductor substrate in a grinding process to provide a ground surface.

18. The method for producing a semiconductor device according to claim 17 , wherein implanting protons is performed through the ground surface of the semiconductor substrate.

19. The method for producing a semiconductor device according to claim 1 , further comprising radiating an electron beam onto the semiconductor substrate.

20. The method for producing a semiconductor device according to claim 19 , further comprising heat treating the semiconductor substrate after radiating the electron beam onto the semiconductor substrate.

21. The method for producing a semiconductor device according to claim 2 , wherein protons from the rear surface have a range equal to or greater than 15 μm.

22. The method for producing a semiconductor device according to claim 21 , wherein, when q is an elementary charge, a drift layer has an average concentration N d , the semiconductor substrate has a permittivity ε S , the semiconductor device has a rated voltage V rate and a rated current density J F , and carriers have a speed which is a saturated speed v sat at which the speed of carriers is saturated with predetermined electric field intensity, then a distance index L is represented by Expression (1) as follows:

L

=

ɛ

S

⁢

V

rate

q

⁡

(

J

F

qv

sat

+

N

d

)

,

and wherein, when the protons have a range from the rear surface of X and the semiconductor substrate has a thickness W 0 , then X=W 0 −γL is established, and γ is equal to or greater than 0.2 and equal to or less than 1.5.