Monocrystalline semiconductor wafer comprising defect-reduced regions and method for producing it
View Patent ↗Monocrystalline semiconductor wafers have defect-reduced regions, the defect-reduced regions having a density of GOI-relevant defects within the range of 0/cm 2 to 0.1/cm 2 and occupy overall an areal proportion of 10% to 100% of the planar area of the semiconductor wafer, wherein the remaining regions of the semiconductor wafer have a significantly higher defect density than the defect-reduced regions. The wafers may be produced by a method for annealing GOI relevant defects in the wafer, by irradiating defined regions of a side of the semiconductor wafer by laser wherein each location is irradiated with a power density of 1 GW/m 2 to 10 GW/m 2 for at least 25 ms, wherein the laser emits radiation of a wavelength above the absorption edge of the wafer semiconductor material and wherein the temperature of the wafer rises by less than 20 K as a result of irradiation.
1. A method for annealing GOI relevant defects in a monocrystalline semiconductor wafer, wherein defined regions of at least one side of the semiconductor wafer are irradiated by means of a laser, wherein each location within the defined regions is irradiated with a power density of 1 GW/m 2 to 10 GW/m 2 for a duration of at least 25 ms, wherein the laser emits radiation having a wavelength lying above the absorption edge of the semiconductor material of which the semiconductor wafer is composed, and wherein the temperature of the semiconductor wafer rises by less than 20 K as a result of the irradiation by means of the laser.
2. The method of claim 1 , wherein the semiconductor wafer is kept at a temperature within the range of 20° C. to 50° C. during irradiation by means of the laser.
3. The method of claim 1 , wherein the semiconductor wafer is substantially a round, unpatterned semiconductor wafer.
4. The method of claim 1 , wherein the semiconductor material comprises at least 80% silicon and wherein the laser emits light having a wavelength between 1 μm and 7 μm.
5. The method of claim 4 , wherein the temperature of the semiconductor material at the currently irradiated location is at most 800° C.
6. The method of claim 1 , wherein the irradiation of the defined regions of the at least one side of the semiconductor wafer is effected by scanning the defined regions using a laser beam, whereby the defined regions are converted into defect-reduced regions which have a density of GOI relevant defects within the range of 0/cm 2 to 0.1/cm 2 and occupy overall an areal proportion of 10% to 100% of the planar area of the semiconductor wafer, wherein the remaining regions of the semiconductor wafer have a significantly higher defect density than the defect-reduced regions.
7. The method of claim 1 , wherein following said method of annealing, a monocrystalline semiconductor wafer having defect-reduced regions, wherein said defect-reduced regions have a density of GOI-relevant defects within the range of 0/cm 2 to 0.1/cm 2 and occupy overall an area proportion of 10% to 100% of the planar area of the semiconductor wafer, wherein remaining regions of the semiconductor wafer have a significantly higher defect density than the defect-reduced regions and wherein the GOI relevant defect density in said remaining regions is at least twice as great as in the defect regions, is produced.