Passivation layers for semiconductor devices

A semiconductor device, comprising:

• a first field effect transistor (FET) comprising:
• a first fin structure disposed on a substrate,
• a first passivation layer wrapped around the fin structure, and
• a first epitaxial region of a first conductivity type disposed on the first passivation layer;
• and
• a second FET comprising:
• a second fin structure disposed adjacent to the first fin structure on the substrate,
• a second passivation layer wrapped around the second fin structure, and
• a second epitaxial region of a second conductivity type disposed on the second passivation layer, wherein the first and second conductivity types are different from each other.

A method for fabricating a semiconductor device, comprising:

• forming a fin structure with a stack of first and second semiconductor layers arranged in an alternating configuration on a substrate;
• depositing a passivation layer on the fin structure and the substrate;
• forming an epitaxial region on a first portion of the fin structure;
• forming nanostructured channel regions in a second portion of the fin structure;
• and
• forming a nanosheet (NS) structure wrapped around the nanostructured channel regions.