Careful control of the chemical purity of these allows precise control of their electronic properties. While germanium was used first in this capacity because it was easier to purify, silicon is superior. Since the late '60s, it's been almost all silicon. Finally, yes, silicone and silicon are related. The polymer silicone contains the element silicon as part of its backbone structure.
Silicone is chemically inert, flexible, stable, and resistant to weathering and temperature.
So it's excellent for use in medical devices, presuming people stop falsely blaming it for their diseases. Cecil's Mailbag is researched and written by members of the Straight Dope Science Advisory Board, Cecil's online auxiliary. Inc. All rights reserved. No material contained in this site may be republished or reposted without express written permission. The Straight Dope is a registered trademark of Chicago Reader, Inc.