Zone melting apparatus for monocrystallizing semiconductor layer on insulator layer

A zone melting apparatus for monocrystallizing a semiconductor layer deposited on an insulator layer, comprising:

• a support plate for supporting a layered substance including said semiconductor layer and said insulator layer;
• an upper elongated heated for zone melting of said semiconductor layer, said upper heater being disposed above and parallel to said semiconductor layer;
• a plurality of lower elongated heaters for heating the whole of said layered substance, said lower heaters being disposed in a plane below and parallel to said support plate and the axis of each of said lower heaters being substantially perpendicular to the axis of said upper heater;
• a plurality of power suppliers for supplying predetermined amounts of electric power to individual heaters in said plurality of lower heaters;
• a temperature sensor disposed at a predetermined position in said support plate for generating an output corresponding to the temperature of said layered substance thereat;
• a controller for controlling said power suppliers in response to the output of said temperature sensor, said controller being capable of controlling said power suppliers to supply large amounts of electric power to those of said lower heaters located more remotely from the central portion to said layered substance than to those local heaters located closer to said central portion, whereby the temperature in said central portion of said layered substance is controlled to be lower than that in the outer edge portions of said layered substance;
• and
• means for moving said upper heater relative to said layered substance in the axial direction of said lower heaters.