Semiconductor device with improved word line resistance

A semiconductor device, comprising:

• an alternating stack of conductive layers and dielectric layers disposed over a substrate;
• a channel layer disposed in a through portion, penetrating through the alternating stack;
• a first blocking layer disposed in the through portion, surrounding an outer wall of the channel layer;
• a continuous etch stop layer continuous along the through portion, surrounding an outer wall of the first blocking layer;
• and
• a second blocking layer disposed between the channel layer and the first blocking layer,
• wherein the continuous etch stop layer is formed of a single layer of a carbon-containing material, and
• wherein the continuous etch stop layer is thinner than the first blocking layer.