METHOD OF FORMING HORIZONTAL GATE ALL AROUND STRUCTURE

摘要

This disclosure provides a horizontal structure by using a double STI recess method. The double STI recess method includes: forming a plurality of fins on the substrate; forming shallow trench isolation between the fins; performing first etch-back on the shallow trench isolation; forming source and drain regions adjacent to channels of the fins; and performing second etch-back on the shallow trench isolations to expose a lower portion of the fins as a larger process window for forming gates of the fins. Accordingly, compared to conventional methods limited by fin height from the STI, the double STI recess method provides greater fin height, which is a larger process window for HGAA nanowire formation, to easily produce multi-stack HGAA nanowires with high current density. The number of layers used in the multi-stack HGAA nanowires is not limited and may vary based on different designs.

主权项

1. A method of forming a semiconductor device having a horizontal gate all around structure on a substrate, the method comprising:
forming a plurality of fins on the substrate, each fin comprising a top channel layer, a bottom channel layer below the top channel layer, a top sacrificial layer between the top channel layer and the bottom channel layer, and a bottom sacrificial layer between the substrate and the bottom channel layer; forming a shallow trench isolation between the fins; etching the shallow trench isolation to expose a portion of the fins above a first level; etching the shallow trench isolation to expose the portion of the fins above a second level which is lower than the first level; and removing the top sacrificial layer and the bottom sacrificial layer above the second level.