▎ 摘　　要

NOVELTY - Controllable step-shape pre-treatment of silicon carbide substrate comprises e.g. (i) placing the cleaned silicon carbide substrate on a susceptor in a chemical vapor deposition chemical vapor deposition (CVD) apparatus, (ii) setting the reaction chamber pressure to 70-150 mbar and the hydrogen flow rate to 50-150 l/minute, and heating, (iii) maintaining the pressure and hydrogen flow rate unchanged, continuously heating, and simultaneously passing the 1-5 sccm carbon source assisted etching at the temperature rising stage, (iv) maintaining the pressure, temperature and hydrogen flow rate unchanged, slowly increasing the flow rate of the carbon source to 5-50 sccm by linear ramping, and assisting hydrogen etching for 5-20 minutes, (v) closing the carbon source into the reaction chamber valve, and etching pure hydrogen, (vi) passing 5-50 sccm of silane assisted hydrogen etching into the reaction chamber for 5-20 minutes, and (vii) taking out the pretreated silicon carbide substrate. USE - The silicon carbide substrate is useful in pyroletic preparation of graphene (claimed). ADVANTAGE - The method removes the sub-damage layer on the surface of the substrate; can make the growth of graphene is more uniform. DETAILED DESCRIPTION - Controllable step-shape pre-treatment of silicon carbide substrate comprises (i) placing the cleaned silicon carbide substrate on a susceptor in a chemical vapor deposition chemical vapor deposition (CVD) apparatus, (ii) setting the reaction chamber pressure to 70-150 mbar and the hydrogen flow rate to 50-150 l/minute, heating the system at 1400-1450 degrees C, (iii) maintaining the pressure and hydrogen flow rate unchanged, continuously heating to the etching temperature of 1500-1600 degrees C, and simultaneously passing the 1-5 sccm carbon source assisted etching at the temperature rising stage, (iv) maintaining the pressure, temperature and hydrogen flow rate unchanged, slowly increasing the flow rate of the carbon source used in the step (iii) to 5-50 sccm by linear ramping, and assisting hydrogen etching for 5-20 minutes, (v) closing the carbon source into the reaction chamber valve, etching pure hydrogen for 5-20 minutes, (vi) passing 5-50 sccm of silane assisted hydrogen etching into the reaction chamber for 5-20 minutes, (vii) maintaining the pressure in the reaction chamber and the flow rate of hydrogen constant, turning off the silane into the reaction chamber valve, and turning off the RF source, cooling to room temperature, filling the argon into the reaction chamber to atmospheric pressure, and taking out the pretreated silicon carbide substrate.