Semiconductor device and method for preparing same

A method for preparing a semiconductor device, comprising:

• providing a semiconductor substrate, and sequentially forming a gate dielectric layer, a first conductive layer, and a support layer with a through hole on the semiconductor substrate;
• forming a barrier layer and a second conductive layer in the through hole of the support layer, the barrier layer being formed between the support layer and the second conductive layer and covering an inner wall face of the through hole;
• removing the support layer and a part of the first conductive layer located below the support layer to form a primary gate pattern and expose the gate dielectric layer;
• forming a gate sidewall protective layer on a sidewall of the primary gate pattern;
• forming an insulating layer on a top of the primary gate pattern, a surface of the gate sidewall protective layer and a surface of the exposed part of the gate dielectric layer;
• and
• removing a part of the insulating layer and a part of the gate dielectric layer to retain the insulating layer formed on the top of the primary gate pattern and the surface of the gate sidewall protective layer, and to retain the gate dielectric layer covered by the primary gate pattern, the gate sidewall protective layer, and the insulating layer on the surface of the gate sidewall protective layer.