Sacrificial layer fin isolation for fin height and leakage control of bulk finFETs

摘要

The present disclosure relates to a structure and method for fin isolation in bulk FinFETs. A sacrificial portion is formed between the actual fin and the substrate, which gets selectively removed at a later stage of processing to reveal a cavity which extends all the way under the fin. This helps prevent source/drain leakage as there is no path for current flow between the fin and bulk substrate. Furthermore, this method of formation helps in precise control of fin-height in bulk FinFETs.

主权项

1. An integrated circuit (IC) including one or more FinFET devices formed on a semiconductor substrate, the IC comprising:
a gate electrode which overlies the semiconductor substrate and which has a gate dielectric on an underside of the gate electrode; a fin of semiconductor material suspended from the gate dielectric, wherein a cavity separates a lower surface of the suspended fin from a region of the semiconductor substrate aligned under the fin; and a pair of sidewall spacers on opposing sidewalls of the suspended fin, wherein the pair of sidewall spacers have upper surfaces below an upper surface of the gate electrode and lower surfaces below the lower surface of the suspended fin.