Methods for manufacturing non-volatile memory devices including peripheral transistors with reduced and less variable gate resistance are described. In some embodiments, a NAND-type flash memory may include floating-gate transistors and peripheral transistors (or non-floating-gate transistors). The peripheral transistors may include select gate transistors (e.g., drain-side select gates and/or source-side select gates) and/or logic transistors that reside outside of a memory array region. A floating-gate transistor may include a floating gate of a first conductivity type (e.g., n-type) and a control gate including a lower portion of a second conductivity type different from the first conductivity type (e.g., p-type). A peripheral transistor may include a gate including a first layer of the first conductivity type, a second layer of the second conductivity type, and a cutout region including one or more sidewall diffusion barriers that extends through the second layer and a portion of the first layer.