A diagram showing anisotropic wet etching in silicon, showing the undercut under the resist. The etch rate in the &lt;111&gt; direction is much slower (about 100× slower) than in the &lt;100&gt; direction.
<a href="//commons.wikimedia.org/wiki/User:Inductiveload" title="User:Inductiveload">Inductiveload</a>
2010-05-14
<span class="int-own-work" lang="en">Own work</span>