Self-Aligned Dual Depth Isolation and Method of Fabrication

摘要

FDSOI devices and methods for the fabrication thereof are provided. In one aspect, a method for fabricating a device includes the following steps. A wafer is provided having a substrate, a BOX and a SOI layer. A hardmask layer is deposited over the SOI layer. A photoresist layer is deposited over the hardmask layer and patterned into groups of segments. A tilted implant is performed to damage all but those portions of the hardmask layer covered or shadowed by the segments. Portions of the hardmask layer damaged by the implant are removed. A first etch is performed through the hardmask layer to form a deep trench in the SOI layer, the BOX and at least a portion of the substrate. The hardmask layer is patterned using the patterned photoresist layer. A second etch is performed through the hardmask layer to form shallow trenches in the SOI layer.