A method for manufacturing a FinFET, and FinFETs are provided. In various embodiments, the method for manufacturing a FinFET includes forming a fin structure over a substrate. Next, a dummy gate is deposited across over the fin structure. The method continues with forming a pair of first spacers on sidewalls of the dummy gate. Then, a source/drain region is formed in the fin structure not covered by the dummy gate. The method further includes removing the dummy gate to expose the fin structure. After that, the first spacers are truncated, and a gate stack is formed to cover the exposed fin structure and top surfaces of the first spacers.