Patent ID: 7368015

Claim:
An apparatus, comprising: a stationary crucible operable to be sealed to a nitrogen-containing gas, the crucible being chemically inert to at least ammonia at a temperature in a range of about 400 degrees Celsius to about 2500 degrees Celsius, and the crucible having an inner surface defining at least a first volume and a second volume; an energy source operable to supply thermal energy to the crucible; and a controller operable to control the energy source to selectively direct sufficient thermal energy to the first volume within the crucible to attain a first temperature in a range of from about 400 degrees Celsius to about 2500 degrees Celsius, wherein the thermal energy is sufficient to initiate, sustain, or both initiate and sustain growth of a crystal in the first volume, and the first temperature in the first volume being controllable separately from a second temperature in the second volume.