US Patent 11916073 Stacked complementary field effect transistors

A complementary field effect transistor (CFET) structure including a first transistor disposed above a second transistor, a first source/drain region of the first transistor disposed above a second source/drain region of the second transistor, wherein the first source/drain region comprises a smaller cross-section than the second source/drain region, a first dielectric material disposed in contact with a bottom surface and vertical surfaces of the first source/drain region and further in contact with a vertical surface and top surface of the second source/drain region, and a second dielectric material disposed as an interlayer dielectric material encapsulating the first and second transistors.