Protection against charging damage in hybrid orientation transistors

Abstract

A chip can include a CMOS structure having a bulk device disposed in a first region of a semiconductor substrate in conductive communication with an underlying bulk region of the substrate, the first region and the bulk region having a first crystal orientation. An SOI device is disposed in a semiconductor-on-insulator ('SOI') layer separated from the bulk region of the substrate by a buried dielectric layer, the SOI layer having a different crystal orientation from the first crystal orientation. In one example, the bulk device includes a p-type field effect transistor ('PFET') and the SOI device includes an n-type field effect transistor (“NFET”) device. Alternatively, the bulk device can include an NFET and the SOI device can include a PFET. When the SOI device has a gate conductor in conductive communication with a gate conductor of the bulk device, charging damage can occur to the SOI device, except for the presence of diodes in reverse-biased conductive communication with the bulk region. The diodes are operable to conduct a discharge current to the bulk region when either a voltage on the gate conductor or a voltage on the source or drain region of the SOI device exceeds a diode's breakdown voltage.