Semiconductor Device and Method of Manufacturing the Same

A method of manufacturing semiconductor devices, comprising:

• forming a tunnel insulating layer and a conductive layer for a floating gate over a semiconductor substrate;
• forming a first trench in the semiconductor substrate by partially etching the conductive layer for the floating gate, the tunnel insulating layer and the semiconductor substrate;
• forming a first ion implantation region in the semiconductor substrate of inner walls of the first trench by performing a first ion implantation process;
• forming a second trench extending from the first trench by etching the semiconductor substrate of a bottom of the first trench;
• forming a second ion implantation region in the semiconductor substrate of inner walls of the second trench by performing a second ion implantation process;
• forming an isolation structure by filling the first and the second trench with an insulating layer;
• exposing an active region of the semiconductor substrate by etching the conductive layer for the floating gate and the tunnel insulating layer in a direction of a word line;
• and
• forming a junction region in the semiconductor substrate of the exposed active region by performing a third ion implantation process,
• wherein a depth of the first trench is shallower than the junction region.

A semiconductor device, comprising:

• an isolation structure having a first and a second trench formed in a semiconductor substrate;
• a first ion implantation region formed in the semiconductor substrate of inner walls of the first trench having a first impurity concentration;
• and
• a second ion implantation region formed in the semiconductor substrate of inner walls of the second trench having a second impurity concentration which is lower than the first impurity concentration,
• wherein a depth of the first trench is shallower than that of a junction region.