Researchers from Tokyo University of Agriculture & Technology (TUAT), ORC Manufacturing Co. Ltd. and Techno Research., Ltd achieved high-quality crystallization of amorphous silicon film by developing rapid heating technology with the microwave induced wireless heating lamp.
The wireless lamp is excellent in energy saving, durability and maintainability, and it can be expected to be developed into a new heating device that is unprecedented. They published online on February 7, 2019 in IEEE Access of the Institute of Electrical and Electronics Engineers (IEEE). Article title: Carbon Heating Tube Used for Rapid Heating System
Power saving of a heating equipment is required from environmental consideration. In addition, there is a high demand for a long-life heating lamp that does not cause disconnection by heat stress and a lamp unit that is less frequently replace and easily to set. Power cost reduction, maintenance cost reduction and downtime reduction are expected to have a ripple effect in all product manufacturing fields that require heating.
This research was conducted by the research team of Professor Toshiyuki Sameishima, Associate Professor Takuji Arima, Assistant Professor Harumi Hasumi and others at Tokyo University of Agriculture and Technology Graduate School of Engineering, Oak Manufacturing Co., Ltd., and Techno Research Inc. This work was partially supported by Japan Science and Technology Agency ASTEP (No. AS3015022S).
The research team has developed an electrodeless lamp, carbon heating tube (CHT), in which carbon particles filled in a quartz tube with argon gas. When the CHT was irradiated with 200 W of microwave, the carbon particles absorbed the microwave and heated to 1279oC. CHT does not require electrical wiring which is excellent in durability. Also, it is an energy saving type heating lamp which does not generate leaks heat through the wiring.
Moreover, no need for rare metals so it possible to manufacture inexpensively. This time we made a prototype of rapid heating equipment using CHT. The microwave introduced into the chamber through the waveguide tube is effectively absorbed by the CHT. The CHT temperature was measured by a radiation thermometer and controlled the microwave power to adjust the heating temperature. Using this heating system to crystallize an amorphous silicon thin film sample formed on a 4-inch quartz glass substrate.
The analysis results of the spectral reflectance spectrum and the Raman scattering spectrum showed a high quality crystallized film and a high crystallization ratio of 0.92 which comparable to the laser crystallized film was formed over the entire surface of the sample. The present results show the possibility of various applications of heating system using CHT.