Etching silicon carbide by plasma etching process, comprises etching silicon carbide with first ionized process gas, which contains fluorine-containing gas, and etching silicon carbide with second ionized process gas, which contains oxygen

摘要

The method comprises etching a silicon carbide with a first ionized process gas, which contains fluorine-containing gas, and etching the silicon carbide with a second ionized process gas, which contains oxygen, where the two etching steps are alternatively carried out. The mole fraction of the fluorine-containing gas in the first process gas is 90% and the mole fraction of oxygen in the second process gas is 90%. The two etching steps are partially temporally overlapped, where the temporal overlap is 0.5-3 seconds. The first process gas and/or the second process gas comprise portion of argon. The method comprises etching a silicon carbide with a first ionized process gas, which contains fluorine-containing gas, and etching the silicon carbide with a second ionized process gas, which contains oxygen, where the two etching steps are alternatively carried out. The mole fraction of the fluorine-containing gas in the first process gas is 90% and the mole fraction of oxygen in the second process gas is 90%. The two etching steps are partially temporally overlapped, where the temporal overlap is 0.5-3 seconds. The first process gas and/or the second process gas comprise portion of argon, where the mole fraction of the argon is 5-10%. An alternating electric field is applied in the etching steps and is applied vertical to the surface of the silicon carbide for the acceleration of plasma ions in the direction of the silicon carbide. The alternating electric field has a frequency of 1 MHz or 13.56 MHz, and is generated with a power that is greater than the power, with which the alternating electric field is generated in the first etching step. The alternating electric field in the etching steps is generated with power of 100 W. The first etching step is carried out for duration of 5-10 seconds and the second etching step is carried out for duration of 5-10 seconds. A gas flow for the first process gas is 10-1000 sccm. A gas flow for the second process gas is 10-1000 sccm. The ionization of the first and second process gases is produced by an inductive coupling and is uprightly maintained. The ionization of the process gases takes place with a power of 1000 W. The silicon carbide is heated at 70[deg] C. The process pressures in the etching steps are less than 20 mTorr. An independent claim is included for a silicon carbide substrate.