[nwiswell]

> out of something that normally doesn't move (polycrystalline silicon)

More commonly, bulk micromachined MEMS devices are monocrystalline.

> and is very fragile at that

Normalizing for density, monocrystalline silicon is stronger than steel!

[rcxdude]

>Normalizing for density, monocrystalline silicon is stronger than steel!

So's glass, and silicon's a lot like glass (very brittle)

[nwiswell]

Glass has a tensile strength more than an order of magnitude below mono-Si. The elastic modulus for soda-lime is within a factor of 2, but that's not usually what is meant by "strength", rather "stiffness".

You're right that fracture toughness is comparable, but that's not usually as relevant in a MEMS context: for one thing there's less potential for unanticipated collisions, but also crack propagation is significantly inhibited at microscopic length scales.

[theideaofcoffee]

Whoops, yep, thanks for the correction! What's a Greek prefix between friends (save for crystal properties).