Carbon Heating Tube Used for Rapid Heating System

Abstract

We report a microwave heating system with a carbon heating tube (CHT) which was made by a 4-mm diameter quartz tube filled with carbon particles and Ar gas at 1400 Pa. A 60-mm-long CHT was set in a cavity in which 2.45-GHz microwave was introduced. Via nearly complete absorption of a microwave power of 200 W by carbon in the CHT during multi-reflection of the microwave in the cavity, the CHT was effectively heated to 1279 • C at 33 s after the microwave initiation, which was observed by the radiationtype thermometer. Moreover, the control of the CHT temperature was demonstrated with a home-made proportional-integral-differential feedback circuit which regulated the magnetron power source using a signal of the thermometer. The control of temperature at 1100 • C was successfully realized. Crystallization of a 58-nm-thick amorphous silicon thin film formed on the glass substrate was demonstrated by mechanically moving the silicon sample just below the heated CHT. A high crystalline volume ratio of 0.92 was achieved. Furthermore, heating of 500-µm-thick-n-type silicon substrate implanted with 1.0 × 10 15 cm −2 phosphorus and boron atoms with the CHT resulted in activation of the doped regions. Rectified diode characteristics were achieved. INDEX TERMS Electromagnetic interference, heat treatment, low-microwave power electronics, PID temperature control, silicon.

Microwave Rapid Heating System Using Carbon Heating Tube

“…The average electric field intensity gradually increased as the electrical conductivity further increased. The calculation supports experimental results of low microwave refection and effective heating of the CHT [11,12]. Figure 4 shows temperature changes with time of the CHT for three setting temperatures of 1000, 1100, and 1200 o C under moving the silicon samples at 0.12 mm/s just below the CHT.…”

“…Many heating technologies have been developed such as laser annealing, plasma jet annealing, and rapid thermal annealing [7][8][9][10]. We have recently developed a lamp of carbon heating tube (CHT), in which 2-m-diameter-carbon powders were filled with inert gas in a quartz tube whose edges were then closed by thermal welding [11]. Conductive carbon is effectively heated via free carrier absorption of the electromagnetic energy with excellent thermal properties of low specific heat and high heat proof [12][13][14].…”

A Temperature-Control System for Continuous-Flow Microwave Heating Using a Magnetron as Microwave Source

“…Generally, as the most economical microwave generator, magnetron has been widely used in various microwave equipment in industry [20], [21]. Due to its low price and good compatibility with the traditional microwave equipment, magnetron is used as the microwave source in this work.…”