In an embodiment, a method includes forming a multi-layer stack including alternating layers of an isolation material and a semiconductor material, patterning the multi-layer stack to form a first channel structure in a first region of the multi-layer stack, where the first channel structure includes the semiconductor material, depositing a memory film layer over the first channel structure, etching a first trench extending through a second region of the multi-layer stack to form a first dummy bit line and a first dummy source line in the second region, where the first dummy bit line and first dummy source line each include the semiconductor material, and replacing the semiconductor material of the first dummy bit line and the first dummy source line with a conductive material to form a first bit line and a first source line.