Vacuum Annealing Process Of Silicon Carbide Crystal

---

Shanghai Gehang Vacuum Technology Co.,Ltd model RVA-669 high temperature vacuum annealing experiment process of SiC crystal in working area 600 x 600 x 900 mm (W x H x L) is as follows:

The invention relates to a high temperature annealing treatment method for silicon carbide crystals, which is characterized in that it includes the following steps:

1. Put 20~50g SiC powder uniformly at the bottom of the annealed graphite crucible to prevent the reverse sublimation of the SiC crystal surface in the high temperature stage.

2. Place the silicon carbide crystal in the annealed graphite crucible, assemble the graphite crucible, and place it in the central part of the coil in the crystal annealing furnace;

3. After the crystal defiring furnace is closed, the true void is extracted in a row, and the true void is less than 5×10-5mbar, and the temperature is raised to 1000~1100℃ for 30min. After the true void is less than 2×10-5mbar, AR gas is filled to the pressure of 500~800mbar;

4. The temperature is raised to 1800~2400℃ for 3h, and the AR gas is continuously filled with a flow rate of 30~60ml/min. The control pressure is 100~300mbar, and the holding time is 5~10h.
According to the high temperature annealing treatment method of the silicon carbide crystal, the characteristic is that after the vacuum degree in Step 3 is less than 2×10-5mbar, the step of filling AR gas to the pressure of 500~800mbar is repeated for 1 to 4 times.

(1) the purity of silicon carbide powder ≥ 99.9%.
(2) The annealed graphite crucible is made of graphite with a density of ≥ 1.7g/cm3, and a bracket is arranged on both sides of the middle part of the inner wall.
(3) The maximum number of silicon carbide crystals in the annealed graphite crucible is 3.

Editing by Frank Lee
Copyright ：SIMUWU Vacuum Furnace

Learn More : Vacuum Annealing Furnace RVA- Series