Method of forming semiconductor device having a GAA type transistor

Abstract

In a method of fabricating a semiconductor device having a gate all around (GAA) structure transistor, an SOI substrate having a SOI layer, a buried oxide layer, and a bottom substrate is prepared. The SOI layer is patterned to form an active layer pattern. An etch stopping layer having an etch selectivity with respect to the buried oxide layer and the active layer pattern is stacked on the active layer pattern. The etch stopping layer pattern is patterned and removed at the gate region crossing the active layer pattern at the channel region, to form an etch stopping layer pattern and to expose the buried oxide layer. The buried oxide layer is isotropically etched using the etch stopping layer pattern as an etch mask to form a cavity at the channel region bottom of the active layer pattern. A conductive material fills the cavity and a space between the etch stopping layer pattern at the gate region. In this manner, the number of photolithography processes required for forming the device is reduced.

Dependencies are inferred from the claim text.