Barrier layer above anti-punch through (APT) implant region to improve mobility of channel region of fin field effect transistor (FinFET) device structure

摘要

A fin field device structure and method for forming the same are provided. The FinFET device structure includes a substrate and a fin structure extending from the substrate. The FinFET device structure also includes an anti-punch through implant (APT) region formed in the fin structure and a barrier layer formed on the APT region. The barrier layer has a middle portion and a peripheral portion, and the middle portion is higher than the peripheral portion. The FinFET device structure further includes an epitaxial layer formed on the barrier layer.