A method includes planarizing a protective layer over gate materials overlying a recessed region in a substrate. The planarizing includes forming a first planarized surface by planarizing a sacrificial layer over the protective layer, and forming a second planarized surface of the protective layer by etching the first planarized surface of the sacrificial layer at an even rate across the recessed region. An etch mask layer is formed over the second planarized surface, and control gate stacks are formed in the recessed region by etching the gate materials.