What is the Yield Strength of Silicon for MEMs Applications?

[TylerJames]

So I'm doing research with MEMs so we're going to be making silicon wafers that will have little cantilever beams on them which will act as an accelerometer. I need to design it so the beams break at certain forces but to do that I need the yield strength of silicon (that is the correct property isn't it?) and I can't find it anywhere. I'm thinking maybe pure silicon is not the material that's used in MEMs so if someone could point me in the direction to where I could find those mechanical properties that'd be awesome! Thanks

Tyler

 

[phyzguy]

Here's a good source:

http://parts.jpl.nasa.gov/docs/JPL%20PUB%2099-1D.pdf

 

[Mapes]

Silicon doesn't yield; it's brittle, so it fractures. And just like any brittle material, its tensile strength is very sensitive to surface properties and defects. That's why you'll probably find a large range of reported values for tensile strength, and why you'll probably be disappointed if you expect your structures to break reliably at a certain load every time.

You might find Cook's "Strength and sharp contact fracture of silicon," J Mater Sci 41 (2006) to be useful.