Process for manufacturing a monocrystalline silicon semiconductor wafer, and monocrystalline silicon semiconductor wafer
A semiconductor wafer of monocrystalline silicon is produced, in the following order: growing a single crystal of silicon by the CZ method; dividing off a wafer consisting completely of an N region, in which there are no agglomerates of silicon interstitials or vacancies having a diameter of more than 20 nm, and has an oxygen concentration of not less than 5.3×10 17 atoms/cm 3 and not more than 5.9×10 17 atoms/cm 3 and a nitrogen concentration of not more than 1.0×10 12 atoms/cm 3 ; executing a three separate rapid thermal annealing (RTA) treatments of the wafer at temperatures within different temperature ranges over different time periods in a different atmospheres of argon with and without ammonia.
1 . A method for producing a semiconductor wafer of monocrystalline silicon, the method comprising in the following order:
growing a single crystal of silicon by the Czochralski (CZ) method;
dividing at least one semiconductor wafer of monocrystalline silicon from the single crystal, wherein the semiconductor wafer consists completely of an N region, in which there are no agglomerates of silicon interstitials or vacancies having a diameter of more than 20 nm, and has an oxygen concentration of not less than 5.3×10 17 atoms/cm 3 and not more than 5.9×10 17 atoms/cm 3 and a nitrogen concentration of not more than 1.0×10 12 atoms/cm 3 ;
executing a first rapid thermal annealing (RTA) treatment of the semiconductor wafer at a first temperature in a first temperature range of not less than 750° C. and not more than 1100° C. over a first period of not less than 10 s and not more than 30 s in a first atmosphere of argon and ammonia in a ratio of not less than 1:2 and not more than 1:0.75;
executing a second RTA treatment of the semiconductor wafer at a second temperature in a second temperature range of not less than 1190° C. and not more than 1280° C. over a second period of not less than 20 s and not more than 35 s in a second atmosphere of argon; and
executing a third RTA treatment of the semiconductor wafer at a third temperature in a third temperature range of not less than 1160° C. and not more than 1180° C. over a third period of not less than 15 s and not more than 25 s in a third atmosphere of argon and ammonia in a ratio of not less than 8:10 and not more than 3:2.
2 . The method as claimed in claim 1 , which further comprises a fourth RTA treatment of the semiconductor wafer at a fourth temperature in a fourth temperature range of not less than 1130° C. and not more than 1145° C. over a fourth period of not less than 25 s and not more than 35 s in a fourth atmosphere of argon.
3 . A semiconductor wafer of monocrystalline silicon having a front side and a back side, consisting of an N region, comprising
an interstitial oxygen concentration of not less than 5.3×10 17 atoms/cm 3 and not more than 5.9×10 17 atoms/cm 3 ; and
a nitrogen concentration, which decreases from the front side and from the back side into the interior of the semiconductor wafer and in a depth of 50 μm from the front side is not less than 2.0×10 15 atoms/cm 3 .
4 . The semiconductor wafer as claimed in claim 3 , wherein the nitrogen concentration in a near-surface region of the back side is lower than in a near-surface region of the front side.
5 . The semiconductor wafer as claimed in claim 3 , which comprises:
a denuded zone, which extends from the front side to a depth of not less than 10 μm and not more than 20 μm into the interior of the semiconductor wafer, and
an underlying region with BMDs of a density of 5.0×10 9 cm −3 to 7.0×10 9 cm −3 .