Semiconductor component and method for fabricating the same

A method for fabricating a semiconductor component comprising:

• providing a semiconductor substrate comprising an array region, a periphery region and a boundary open region isolating the array region from the periphery region;
• depositing a first oxide layer on the array region;
• depositing a first polysilicon layer on the semiconductor substrate to cover the first oxide layer, the periphery region and the boundary open region;
• depositing a second oxide layer on the first polysilicon layer;
• removing a portion of the second oxide layer on the array region and the boundary open region, and removing a portion of the first polysilicon layer on the array region and the boundary open region;
• forming a trench on the array region, wherein the trench passing through the first oxide layer;
• depositing a second polysilicon layer to cover the first oxide layer, the trench, the boundary open region, and a remaining portion of the second oxide layer on the periphery region, the second polysilicon filling the trench;
• removing a portion of the second polysilicon layer outside the trench, and removing the remaining portion of the second oxide layer on the periphery region;
• depositing a metal layer to cover the first oxide layer, a remaining portion of the second polysilicon layer in the trench, the boundary open region, and a remaining portion of the first polysilicon layer on the periphery region;
• forming a mask on the metal layer, wherein a portion of the metal layer on the boundary open region is exposed from the mask;
• forming an opening to expose the boundary open region by etching the portion of the metal layer on the boundary open region;
• depositing an oxide in the opening;
• and
• exposing the first oxide layer and forming a bitline corresponding to the trench by an etching process.