METHOD OF PRIMARY ANNEALING FOR PROCESSING SILICON-CARBIDE TUBES Russian patent published in 2009 - IPC H01L21/22 

FIELD: physics; conductors.

SUBSTANCE: invention relates to the technology of making power silicon transistors and semicoductor devices, particularly to methods of processing silicon-carbide tubes, used in high-temperature processes in diffusion furnaces. The method of primary annealing silicon-carbide tubes involves two-step processing: at the first step, temperature - T=400°C, nitrogen consumption - N₂ - 600 l/h, time - τ=90 minutes, temperature increase - T=1200°C, nitrogen consumption - N₂ - 600 l/h, rate of temperature increase - 5°C per minute; at the second step temperature - T=1200°C, oxygen consumption - O₂ - 600 l/h, hydrochloric acid HCl - 20 l/h, processing time - τ=8 hours, temperature fall - T=850°C, nitrogen consumption - N₂ - 600 l/h, rate of temperature fall -3°C per minute. At the end of processing, the tubes are put into a solution of hydrofluoric acid and deionised water in ratio components: HF: H₂O = 1:10 at room temperature for 10 minutes, after which the tubes are washed in deionised water for 15-20 minutes. Quality of processing is determined using indicator paper.

EFFECT: invention allows for removing different impurities and preventing formation of defects on a silicon-carbide tube.