Method of manufacturing semiconductor devices and semiconductor device containing hydrogen-related donors
Crystal lattice defects are generated in a horizontal surface portion of a semiconductor substrate and hydrogen-related donors are formed in the surface portion. Information is obtained about a cumulative dopant concentration of dopants, including the hydrogen-related donors, in the surface portion. Based on the information about the cumulative dopant concentration and a dissociation rate of the hydrogen-related donors, a main temperature profile is determined for dissociating a defined portion of the hydrogen-related donors. The semiconductor substrate is subjected to a main heat treatment applying the main temperature profile to obtain, in the surface portion, a final total dopant concentration deviating from a target dopant concentration by not more than 15%.
1. A method of manufacturing a semiconductor device, the method comprising:
generating crystal lattice defects in a horizontal surface portion of a semiconductor substrate;
forming hydrogen-related donors in the surface portion;
obtaining information about a cumulative dopant concentration of dopants including the hydrogen-related donors, in the surface portion;
determining, based on the information about the cumulative dopant concentration, a main temperature profile for dissociating a defined portion of the hydrogen-related donors; and
subjecting the semiconductor substrate to a main heat treatment applying the main temperature profile to obtain, in the surface portion, a final total dopant concentration deviating from a target dopant concentration by not more than 15%.
2. The method of claim 1 , wherein the surface portion contains extrinsic dopants and the cumulative dopant concentration is the sum of an extrinsic net dopant concentration and a preparatory hydrogen-related donor concentration after the forming of the hydrogen-related donors.
3. The method of claim 1 , wherein the semiconductor substrate contains extrinsic donors and an extrinsic net dopant concentration is at least 1E13 cm −3 .
4. The method of claim 1 , wherein the semiconductor substrate contains extrinsic donors and an extrinsic net dopant concentration is at most 5E12 cm −3 .
5. The method of claim 1 , wherein the semiconductor substrate is intrinsic.
6. The method of claim 1 , wherein forming the hydrogen-related donors comprises a preparatory heat treatment for diffusing hydrogen into the surface portion.
7. The method of claim 1 , wherein generating the crystal lattice defects comprises irradiating the semiconductor substrate with protons.
8. The method of claim 7 , further comprising:
after implanting the protons, thinning the semiconductor substrate from a side opposite to the front surface so that a base portion comprising an end-of-range peak of the proton implant is removed.
9. The method of claim 7 , wherein forming the hydrogen-related donors comprises a preparatory heat treatment for diffusing the implanted protons into the surface portion.
10. The method of claim 9 , wherein a maximum temperature applied in the preparatory heat treatment is above 470° C. and at most 510° C.
11. The method of claim 1 , wherein a maximum temperature applied in the main heat treatment is above 510° C.
12. The method of claim 1 , wherein at least 50% of a total duration of the main temperature profile is an isothermal process given by a constant main process temperature and a main process time for which the constant main process temperature is applied.
13. The method of claim 1 , further comprising:
forming anode/body wells in the semiconductor substrate,
wherein the anode/body wells form first pn junctions with cathode/drain structures,
wherein the cathode/drain structures comprise drift zones in the surface portion,
wherein a dopant concentration in the drift zones is equal to the final total dopant concentration.
14. The method of claim 1 , wherein the information about the cumulative dopant concentration comprises a capacitive/voltage measurement across at least one of a pn junction and a Schottky contact formed by the surface portion.
15. The method of claim 14 , wherein a contact probe is pressed against a section of the front surface exposing the surface portion.
16. The method of claim 1 , further comprising:
forming an interlayer dielectric at a front side of the semiconductor substrate before subjecting the semiconductor substrate to the main heat treatment.
17. The method of claim 1 , further comprising:
forming a plurality of separated semiconductor dies from the semiconductor substrate after subjecting the semiconductor substrate to the main heat treatment.
18. The method of claim 1 , wherein at least 25% of donors in the semiconductor substrate are hydrogen-related donors after the main heat treatment.
19. The method of claim 1 , wherein an intrinsic oxygen concentration in the semiconductor substrate is in a range from 1E17 cm −3 to 6E17 cm −3 .
20. The method of claim 1 , wherein a substitutional carbon concentration in the semiconductor substrate is in a range from 1E14 cm −3 to 5E15 cm −3 .
21. The method of claim 1 , further comprising:
after the main heat treatment, implanting protons to form a field stop layer in the semiconductor substrate.
22. The method of claim 21 , further comprising:
subjecting the semiconductor substrate to a supplementary heat treatment which activates the protons to form the field stop layer,
wherein a maximum temperature applied in the supplementary heat treatment is below 420° C.
23. The method of claim 1 , wherein the semiconductor substrate is subjected to the main heat treatment before forming a first metallization at a front side.