Patent ID: 8765534

Claim:
A method comprising: obtaining a substrate structure comprising: a first substrate; a second substrate located over a first portion of the first substrate and separated from the first substrate by a buried layer; and an epitaxial layer located over a second portion of the first substrate and isolated from the second substrate, wherein the second substrate has a higher hole mobility than the epitaxial layer, wherein the epitaxial layer has a higher electron mobility than the second substrate, and wherein the hole and electron mobilities are bulk properties; and forming first and second transistors, the first transistor formed at least partially in the second substrate, the second transistor formed at least partially in or over the epitaxial layer, at least one of the transistors configured to receive one or more signals of at least about 5V; wherein: the first substrate has a first crystalline orientation; the second substrate has a second crystalline orientation; the first substrate comprises p-type silicon having a (100) crystalline orientation; the second substrate comprises n-type silicon having a (110) crystalline orientation; the epitaxial layer comprises silicon germanium; and a cap located over the epitaxial layer comprises p-type silicon, the second transistor formed at least partially in the cap.