Coated semiconductor wafer, and process and device for producing the semiconductor wafer

1. A susceptor for a semiconductor wafer to be employed during deposition of a layer on a front surface of the semiconductor wafer by chemical vapor deposition (CVD), said susceptor composed of a porous gas-permeable material with a porosity of at least 15% and a density of form 0.5 to 1.5 g/cm 3 .

2. The susceptor of claim 1 ,

wherein the gas-permeable material comprises a porous layer of graphite fibers as a porous, gas-permeable material.

3. The susceptor of in claim 1 ,

wherein the gas-permeable material comprises a porous layer of graphite particles as a porous, gas-permeable material.

4. The susceptor of claim 1 , further comprising through holes over a portion of the susceptor.

5. The susceptor of claim 1 , wherein the porosity is random and uniform.

6. The susceptor of claim 1 , further comprising through holes proximate an edge region of the susceptor.

7. The susceptor of claim 1 , wherein said porous, gas-permeable material has a porosity of greater than 20%.

8. The susceptor of claim 1 , wherein said porous, gas-permeable material has a density of from 0.8 to 1.4 g/cm 3 .

9. The susceptor of claim 1 , wherein said porous, gas-permeable material has a porosity greater than 20% and a density of from 0.8 to 1.4 g/m 3 .

10. The susceptor of claim 1 , having no through-holes.

11. The susceptor of claim 1 ,

which includes a coating of silicon carbide on a porous base material, said susceptor remaining porous.

12. The susceptor of claim 11 ,

wherein the thickness of the coating of silicon carbide decreases from a surface of the susceptor toward an interior of the susceptor.

13. A semiconductor wafer having a back surface and a front surface which has been coated by chemical vapor deposition (CVD) and a polished or etched back surface,

wherein the nanotopography of the back surface, expressed as the height fluctuation PV (=peak to valley), is less than 5 nm, and said semiconductor wafer is coated by chemical vapor deposition on its front surface employing a susceptor of claim 1 .

14. A process for producing a semiconductor wafer having a layer deposited on a front surface of said wafer by chemical vapor deposition (CVD) and a polished or etched back surface of said wafer, comprising

placing the semiconductor wafer on a porous susceptor constructed of porous, gas-permeable material with a porosity of at least 15% and a density of from 0.5 to 1.5 g/cm for deposition of the layer, so that the back surface of the semiconductor wafer faces a base of the susceptor; and

passing gaseous substances from a region over the back surface of the semiconductor wafer substantially only through pores in the susceptor into a region over a back surface of the susceptor.