Intel Corporation
Transistors employing carbon-based etch stop layer for preserving source/drain material during contact trench etch

Abstract:

Techniques are disclosed for forming transistors employing a carbon-based etch stop layer (ESL) for preserving source and drain (S/D) material during contact trench etch processing. As can be understood based on this disclosure, carbon-based layers can provide increased resistance for etch processing, such that employing a carbon-based ESL on S/D material can preserve that S/D material during contact trench etch processing. This is due to carbon-based layers being able to provide more robust (e.g., more selective) etch selectivity during contact trench etch processing than the S/D material it is preserving (e.g., Si, SiGe, Ge, group III-V semiconductor material) and other etch stop layers (e.g., insulator material-based etch stop layers). Employing a carbon-based ESL enables a given S/D region to protrude from shallow trench isolation (STI) material prior to contact metal deposition, thereby providing more surface area for making contact to the given S/D region, which improves transistor performance.