Apparatus and method for the production of ingots

A wafer with a monocrystalline structure, the wafer comprising:

• a size of at least 140 mm×140 mm;
• a specific resistance, which in at least three quarters of a surface of the wafer has a variability of less than 5%;
• and
• a mean dislocation density over a surface thereof which is less than 100/cm2.

A wafer produced according to a method comprising the following steps:

• providing an apparatus for producing an ingot, the apparatus comprising a chamber to provide a controllable atmosphere and at least one means for controlling a temperature field in a given volume of growth in the chamber, wherein the temperature field has a temperature gradient in a longitudinal direction, the apparatus further comprising a support for a seed layer, the support being movable in the longitudinal direction inside the chamber and a controllable feeding apparatus for providing feedstock,
• producing an ingot by:
• providing a seed layer on the support, wherein the seed layer defines a cross-sectional area of an ingot to be produced;
• moving the support, such that the seed layer is located at a predetermined position within the volume of growth;
• generating a temperature field with a predetermined vertical temperature gradient and a lateral temperature gradient within the volume of growth, wherein the vertical temperature gradient is in a range of 100 K/m to 10000 K/m and a lateral temperature gradient is at most 1 K/cm;
• providing feedstock on the seed layer by way of the feeding apparatus, wherein the feeding of feedstock and the temperature field within the volume of growth are controlled such that the entire seed layer is covered with a layer of liquid feedstock;
• lowering the support while solidifying the layer of liquid feedstock;
• and
• adding more liquid feedstock from the feeding apparatus;
• dividing the ingot into at least four columns, from which the wafer can be cut.