Semiconductor storage device and preparation method

The invention discloses a semiconductor storage device and a preparation method thereof. The probability of electrical damage of the semiconductor storage device caused by charges of bit line grids can be reduced. The preparation method of the semiconductor storage device provided by the invention comprises the following steps: providing a substrate, forming a plurality of contact windows on the surface of the substrate, forming a stacking structure in the contact windows, and enabling the upper surface of the stacking structure to be higher than the upper surface of the substrate; forming a side wall on the surface of the side wall of the stacked structure; and nitriding the side wall to at least enhance the insulating strength of the surface of the side wall. 本申请公开一种半导体存储装置及制备方法，能够减小位线栅极的电荷造成半导体存储装置电性毁损的几率。本申请提供的一种半导体存储装置的制备方法，包括以下步骤：提供衬底，所述衬底表面形成有多个接触窗，所述接触窗内形成有堆叠结构，且所述堆叠结构的上表面高于所述衬底的上表面；在所述堆叠结构的侧壁表面形成侧墙；对所述侧墙进行氮化处理，以至少增强所述侧墙的表面的绝缘强度。