Self-aligned gate caps with inverted profile for transistor isolation

A dielectric cap layer is introduced as an intermediary between the metal gate structure and the self-aligned contact. This cap layer is conformally deposited over the metal gate and extends laterally to cover the contact region, providing electrical isolation while allowing the contact to be formed through the dielectric cap. The intermediary dielectric material prevents direct electrical contact between the conductive gate and contact layers, eliminating the shorting risk while maintaining close proximity for high integration density.

The solution transitions from a planar two-dimensional layout to a three-dimensional stacked structure. The metal gate is recessed relative to the contact, and a dielectric cap is deposited conformally over the gate structure, creating vertical layering. This dimensional change allows the gate and contact to be in close horizontal proximity while maintaining vertical electrical isolation through the dielectric cap, effectively resolving the contradiction between integration density and electrical isolation.

The metal gate layers are recessed relative to the contact layers before the dielectric cap is deposited. This preliminary action creates the necessary topography for the subsequent conformal dielectric deposition, ensuring that the dielectric cap will cover both the gate structure and the contact region. By performing the recess operation beforehand, the manufacturing process establishes the correct spatial relationships early, simplifying later steps and reducing overall complexity despite the additional recess operation.

The conductor layers are divided into multiple segments: a first conductor layer forming the metal gate and a second conductor layer forming the contact. These segments are separated vertically and horizontally, with the first conductor layer recessed relative to the second. This segmentation allows independent formation and positioning of gate and contact structures, enabling precise control over their relative positions and simplifying the manufacturing process by treating them as separate entities rather than a single integrated structure.