4. Summary

Silicon carbide etching using chlorine trifluoride gas with high etching rate occurs at the temperatures higher than 770 K. Its chemical reaction is as follows: 3SiC· + ·8ClF3 · ¨ ·3SiF4 · + · 3CF4 · + ·4Cl2

The etching rate is 10-20 µm/min and 5 µm/min, for polycrystalline 3C-silicon carbide and single-crystalline 4H-silicon carbide, respectively. The etching rate of Si-face of 4H-silicon carbide is slightly smaller than that of C-face. The etched surface tends to be carbon rich. The etched surface of Si-face of 4H-silicon carbide shows various kinds of morphology: ,%00! z0z(+3z0!),!.01.!/z+"zHJCzxzDEJCz\_z\* z/)++0\$z0zDHJCz^z\$!zw"!z+"zGw/%(%¥ con carbide shows the similar trend, and is entirely very smoother than that of Si-face. Most of the etch pits formed near 700 K at the Si-face and C-face of 4H-silicon carbide show .!(0%+\*/\$%,z!03!!\*z %/(+0%+\*/z.!2!(! z5z0\$!zw.5z0+,+#.,\$^z0z0\$!z/1/0.0!z0!),!.¥ ature of 713 K, the etch pit density showed the maximum value of 4 x 104 cm-2. The etch pit density obtained by this technique is considered to show the crystal quality, particularly, the dislocation density.
