High rate etching of 4H-SiC using a SF6/O-2 helicon plasma

The etch rate of 4H-SiC in a SF6 helicon plasma has been investigated as a function of pressure, power injected in the source, substrate bias voltage, and distance between the substrate holder and the helicon source. The high est etch rate yet reported of 1.35 mu m/min along with good uniformity on 2 in. SiC substrates was achieved when this distance was minimum. Smooth etc hed surfaces free of micromasking have been obtained when using a nickel ma sk and the selectivity SiC/Ni was found to be about 50 under high etch rate conditions. Via holes have been etched to a depth of 330 mu m in 4H-SiC su bstrates. (C) 2000 American Institute of Physics. [S0003-6951(00)03016-3].