Various embodiments provide semiconductor devices including high-K dielectric layer(s) and fabrication methods. An exemplary high-K dielectric layer can be formed by providing a semiconductor substrate including a first region and a second region, and forming a first silicon oxide layer on the semiconductor substrate in the first region. The semiconductor substrate can then be placed in an atomic layer deposition (ALD) chamber to repeatedly perform a selective ALD process. The selective ALD process can include an etching process and/or a purging process in the ALD chamber. By repeatedly performing the selective ALD process, a first high-K dielectric layer can be selectively formed on the first silicon oxide layer in the first region, exposing the semiconductor substrate in the second region.