A method of removing an oxide layer is provided. A metal layer is deposited over an oxide layer formed at a top surface of a germanium substrate. A metal oxide layer is deposited over the metal layer. The metal oxide layer includes a same metal material as the metal layer. The metal layer and the oxide layer are reacted and combined with the metal oxide layer to form a dielectric layer during an anneal process. During the anneal process, the oxide layer is reacted with the metal layer and removed.