A semiconductor process including the following steps is provided. An epitaxial layer is formed on a substrate. An oxide layer is formed on the epitaxial layer, wherein the oxide layer includes a chemical oxide layer, a high-temperature oxide (HTO) layer or a surface modification oxide layer. An ion implant process is performed to the epitaxial layer to form a doped region in the epitaxial layer. The oxide layer is removed by using a diluted hydrofluoric acid (DHF) solution after performing the ion implant process, wherein a volume ratio of water to a hydrofluoric acid (HF) in the DHF solution is 200:1 to 1000:1.