2.6. Melt Convection

The largest CZ crystals grown today weigh several hundreds of kgs, and the size of the crucible corresponds to that of a small bathtub. The freezing interface is located at the top surface of the melt, and that is why the surface areas are colder than those deep in the melt. As the melt expands with the temperature, warmer melt close to the bottom is less dense, and it tends to rise up towards the surface. The viscosity of molten silicon is somewhat less than that of water; that is, there is very little that the viscosity does to slow down melt movements. That, combined with the large volume of the melt, makes it very difficult to control the melt behavior properly. The crystal sizes grown for MEMS applications are, fortunately, ...

Get Handbook of Silicon Based MEMS Materials and Technologies now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.