If the wafers are not polished on both sides, look at the rough side under a
microscope.  You will usually see rectangles and squares if it is <100> and
equilateral triangles if it is <111>.

Roger Brennan

-----Original Message-----
From: Christoph Wild
Subject: [mems-talk] Quick Test of Silicon orientation

I have ordered a batch of silicon wafers without flat.
We ordered 100 oriented wafers, however, now it turns out that some of the
wafes are 111 oriented.
Is there a quick test which allows us to discriminate between 100 and 111
oriented wafers ?