Semiconductor device and methods of formation

Abstract

Air gaps are formed in capacitor structures to reduce parasitic capacitance between closely spaced capacitors. The air gaps may be formed on lateral sides of a deep trench capacitor structure to ensure capacitor-to-capacitor isolation and reduced parasitic capacitance. Air gaps may be formed by selective film deposition and / or by selective removal of sacrificial layers. The dielectric constant of the air gaps is less than the dielectric constant of porous low-k or bulk dielectric materials that may be used in other capacitor structures. The lesser dielectric constant of the air gaps in comparison to that of the porous low-k or bulk dielectric materials reduces the capacitive coupling between adjacent capacitor structures, thus suppressing cross-talk and increasing signal integrity, leading to increased device performance and reliability.

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