Protective structure and fabrication methods for the peripheral circuits of a three-dimensional memory

A semiconductor memory device, comprising:

• a substrate having a first region with peripheral devices, a second region with one or more memory arrays, and a third region between the first and the second regions;
• and
• a protective structure for peripheral devices comprising:
• a first dielectric layer;
• a barrier layer disposed on the first dielectric layer;
• and
• a dielectric spacer formed on a sidewall of the barrier layer and on a top surface of the first dielectric layer,
• wherein the protective structure is disposed over the first region and at least a portion of the third region.

A method for forming a semiconductor memory device, comprising:

• forming peripheral devices in a first region on a substrate;
• forming active device areas in a second region on the substrate;
• forming one or more isolation structures in a third region between the first and the second regions;
• forming a protective structure for peripheral devices, wherein the protective structure comprises the dielectric spacer and remaining portions of the first dielectric layer and the barrier layer, and is disposed over the first region and at least a portion of the third region;
• and
• forming one or more memory arrays in the second region on the substrate.