Author details

shows the nine etch pits observed on the C-face of 4H silicon carbide after the etching at 713 K for 10 min using the 100 % chlorine trifluoride gas. Their diameter was about 10 – 15 µm. This substrate was additionally etched at 713 K at the 100 % chlorine trifluoride gas. Figure 31 (b) shows the surface, 80 µm of which surface was etched off by the additional etching. Figure 31 (b) shows the large and shallow nine etch pits, which were overlapped 3%0\$z!\$z+0\$!.^z\$!z\*1)!.z\* z0\$!z,+/%0%+\*z+"z!0\$z,%0z!\*0!.z%\*z%#1.!^zFDzcdz+..!/,+\* ¥ ed to those in Figure 31 (a), respectively. Thus, over the depth of 80 µm, the origin to cause 0\$!z!0\$z,%0z3/z+\*(1 ! z0+z!4%/0az0\$!z+.%#%\*z+1( z!z0\$!z %/(+0%+\*\_z/1\$z/z0\$!z0\$.! ¥

\$!z.!/1(0/z+0%\*! z%\*z0\$%/z/01 5z%\* %0!z0\$0z0\$!z,%0/z1/! z5z0\$!z!0\$%\*#z1/%\*#z\$(+.¥ ine trifluoride gas at around 713 K has the origin of crystalline imperfection, such as the 0\$.! %\*#z %/(+0%+\*^z+3!2!.\_z0\$!z%\*0!.,.!00%+\*z+"z!0\$z,%0/z3%0\$z.!/,!0z0+z0\$!z1\* !.(5¥ ing dislocation type should be further carefully performed by a comparative investigation [28]. Additionally, the density and shape of etch pit by this technique should be further

Silicon carbide etching using chlorine trifluoride gas with high etching rate occurs at the

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!),!.¥

density obtained by this technique is considered to show the crystal quality, particularly,

Various studies reviewed in this Chapter were performed with Ms. Satoko Oda, Mr. Yusuke 0/1)%\_z
.^z1z/\$.\_z
/^z!%'+z\*'\_z
.^z61\$%'z1.1'3\_z
.^z1/1'!z1'1¥ moto, Dr. Yutaka Miura, Mr. Yoichi Negishi, Dr. Takashi Takeuchi, Prof. Masahiko Aihara, .+"^z
%\*+.1z'! \_z.+"^z%.+\*+1z1\*%! z \* z.+"^z!\*&%z.)'%z +"z+'+\$)z¥ tional University, Mr. Yasushi Fukai, Mr. Katsuya Fukae, Mr. Naoto Takechi, Dr. Yuan Gao,

cm-2. The etch pit

ing dislocation, existing normal to the substrate surface.

126 Physics and Technology of Silicon Carbide Devices

clarified and verified through many characterization.

3SiC· + ·8ClF3 · ¨ ·3SiF4 · + · 3CF4 · + ·4Cl2

temperatures higher than 770 K. Its chemical reaction is as follows:

ature of 713 K, the etch pit density showed the maximum value of 4 x 104

4. Summary

the dislocation density.

Acknowledgements

Hitoshi Habuka\*

Address all correspondence to: habuka1@ynu.ac.jp

Department of Chemical and Energy Engineering, Yokohama National University, Japan
