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 wh

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.