SHALLOW TRENCH ISOLATION LAYER WITH AIR GAP AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A method for fabricating a shallow trench isolation layer with an air gap is provided to reduce capacitance in a substrate while increasing a dielectric constant of an isolation layer by adding a spacer insulation layer to the inside of a trench and by forming an air gap in the trench in a process for depositing a gap-fill insulation layer. CONSTITUTION: A bottom insulation layer pattern(102) for defining a bottom region of a shallow trench isolation layer is formed on a semiconductor substrate(100). A sacrificial layer pattern in which a part of the upper surface of the bottom insulation layer pattern is exposed is formed on the substrate. After a spacer insulation layer(108a) is formed on the sidewall of the sacrificial layer pattern, the sacrificial layer pattern is eliminated. A selective epitaxial growth process is performed on the exposed substrate to form an epitaxial layer(110). A gap-fill insulation layer is deposited to fill the opening between the epitaxial layer wherein an air gap(112) is formed between the spacer insulation layers. The gap-fill insulation layer is planarized to expose the surface of the epitaxial layer so that the shallow trench isolation layer(114a) is formed.