Contact structure and method of forming the same

A memory system device, comprising:

• a semiconductor memory device, comprising:
• a memory stack of gate layers and insulating layers, the gate layers and the insulating layers being stacked alternatingly and forming stair steps in a staircase region;
• a landing structure disposed on a first gate layer of a first stair step of the stair steps in the staircase region, the landing structure comprising an etch stop structure and an isolation stack between the etch stop structure and the first gate layer, the etch stop structure being etch-selective to a contact isolation layer that covers the staircase region;
• a contact structure extending through the contact isolation layer and the landing structure and being connected with the first gate layer of the first stair step;
• and
• a channel structure extending through the memory stack of gate layers and insulating layers in an array region;
• and
• a control circuitry coupled with the semiconductor memory device to control data storage operations on the semiconductor memory device,
• wherein the etch stop structure comprises a same conductive material as the first gate layer, and the etch stop structure is shorter than the isolation stack along a direction parallel to the gate layers.

A method for fabricating a semiconductor device, the method comprising:

• forming a memory stack of gate layers and insulating layers, the gate layers and the insulating layers being stacked alternatingly and forming stair steps in a staircase region;
• forming a landing structure on a first gate layer of a first stair step of the stair steps in the staircase region, the landing structure comprising an upper structure that is an etch stop structure and an isolation stack between the upper structure and the first gate layer, the upper structure being etch-selective to a contact isolation layer that covers the staircase region, the upper structure comprising a same conductive material as the first gate layer, the upper structure being shorter than the isolation stack along a direction parallel to the gate layers;
• and
• forming a contact structure extending through the contact isolation layer and the landing structure, the contact structure being connected with the first gate layer of the first stair step.