Fabrication method for semiconductor devices

A method of fabricating a semiconductor device, comprising:

• providing a semiconductor substrate;
• forming at least a fin structure and at least a gate semiconductor layer on the semiconductor substrate sequentially, wherein the gate semiconductor layer covers a portion of the fin structure;
• forming a sacrificial layer covering the fin structure;
• exposing a side surface of the gate semiconductor layer from the sacrificial layer;
• exposing a top surface of the fin structure from the sacrificial layer after exposing the side surface of the gate semiconductor layer from the sacrificial layer;
• forming a material layer conformally covering the gate semiconductor layer, the fin structure and the sacrificial layer;
• and
• etching the material layer to expose the top surface of the fin structure and concurrently form a first spacer on side surfaces of the gate semiconductor layer.