Growing semiconductor crystalline materials

A method of growing semiconductor crystalline materials comprising the steps:

• providing in a crucible a melt of the material to be grown as a crystal,
• dipping a seed crystal into the melt,
• withdrawing and rotating the seed crystal from the melt,
• maintaining a temperature gradient between the melt and seed crystal, whereby a single crystalline material is grown from the melt,
• during said withdrawing and rotating step, providing a magnetic field that is substantially rotationally symmetrical about the axis of rotation of the crystal and with a component of field parallel to the axis of crystal rotation that is less than 500 gauss at the interface between growing crystal and melt, with a value of magnetic field above 500 gauss at other parts of the melt,
• and maintaining this distribution of magnetic field during growth of the crystal,
• whereby forced convective flows in the melt adjacent the crystal/melt interface are substantially undamped, whilst convective flows in other parts of the melt are damped.