Method for fabricating a doped zone in a semiconductor body

1. A method of manufacturing a semiconductor device, the method comprising:

forming a cell array for a power MOSFET or a power IGBT in a region of a front side of a semiconductor body, the cell array including a plurality of body zones in each of which a source zone of an opposite conductivity is arranged;

forming a terminal electrode in the region of the front side of the semiconductor body, the terminal electrode making contact at least with the source zones;

after forming the cell array and the terminal electrode, thinning the semiconductor body from a rear side opposite the front side;

forming an emitter region at the thinned rear side of the semiconductor body, by implanting dopant particles into the thinned rear side of the semiconductor body;

irradiating the thinned rear side of the semiconductor body with further particles, wherein an irradiation energy or implantation energy for the further particles is chosen such that the further particles penetrate more deeply into the semiconductor body from the thinned rear side than the dopant particles; and

after the implanting and the irradiating, annealing the semiconductor body at a temperature less than the melting point or eutectic temperature of a metal used to form the terminal electrode, to activate the emitter region,

wherein at least irradiation steps with different irradiation energies are carried out for irradiating the thinned rear side of the semiconductor body with the further particles.

2. The method of claim 1 , further comprising:

forming a passivation layer in the region of the front side of the semiconductor body before the annealing of the semiconductor body,

wherein the temperature of the annealing is less that a decomposition temperature of the passivation layer.

3. The method of claim 2 , wherein the passivation layer is a polyimide.

4. The method of claim 1 , wherein the further particles are protons and wherein the annealing is performed in a temperature range of between 350° C. and 450° C.

5. The method of claim 1 , wherein the semiconductor body is thinned to a thickness in a range of between 10 μm to 70 μm.

6. The method of claim 1 , wherein the further particles are protons, and wherein the thinned rear side of the semiconductor body is irradiated at a dose and energy such that in part hydrogen-induced donors are formed from the implanted protons and the hydrogen-induced donors form a field stop zone that is doped more highly than a drift zone in the semiconductor body.

7. The method of claim 1 , further comprising:

applying a metallization to the thinned rear side of the semiconductor body before the annealing of the semiconductor body.

8. The method of claim 7 , wherein the metallization is applied to the thinned rear side of the semiconductor body after the implanting of the dopant particles and before the irradiating with the further particles.

9. The method of claim 1 , wherein an implantation dose of the dopant particles is chosen such that the region of the semiconductor body into which the dopant particles are introduced is at least partially amorphized.

10. The method of claim 1 , further comprising:

before the irradiating, implanting further, non-doping ions into the thinned rear side of the semiconductor body to at least partially amorphize the semiconductor body.

11. The method of claim 1 , further comprising:

before the irradiating, depositing an amorphous semiconductor layer onto the thinned rear side of the semiconductor body.

12. The method of claim 1 , wherein a duration of the annealing is between 30 minutes and 24 hours.