Abstract
There have been reported three types of magnetic fields to be applied to Czochralski (CZ) silicon crystal growths. This paper reviews the characterictics of impurity concentration and distribution in the crystals grown under the three magnetic fields, and summarizes, as follows: (1) A transverse magnetic field application produces a low or a high oxygen concentration which has not been obtained by the conventional CZ with no magnetic field. However, some serious problems often take place when we once want to obtain the same concentration as that by the conventional CZ which is available for LSI use. The problems are the degradations of oxygen and dopant distributions, and dislocation generations. (2) A vertical magnetic field application enables to obtain various oxygen concentration levels. However, the distributions are usually very inhomogeneous. (3) A cusp magnetic field application enables to obtain various oxygen concentration levels including that by the conventional CZ, and the obtained distributions of oxygen and dopant are always very homogeneous. These advantageous effects are originally caused by the axially symmetric two-dimensional distribution. This is very different from the substantially one-dimensional distribution of a transverse or a vertical magnetic field.
