Nonvolatile Memory Devices and Methods of Forming the Same

A method of forming a nonvolatile memory device comprising:

• forming a plurality of word lines on a semiconductor substrate of a first conductivity type, each of the plurality of word lines comprising a floating gate of a second conductivity type;
• forming a ground select line and a string select on the substrate on respective sides of the word lines;
• and
• forming an impurity region of the second conductivity type underlying a first word line adjacent the ground select line.

A method of forming a nonvolatile memory device comprising:

• forming impurity regions of a second conductivity type in a semiconductor substrate of a first conductivity type;
• forming word lines, each including a floating gate of the second conductivity type, on respective ones of the impurity regions;
• forming a ground select line and a string select line on the substrate on respective sides of the word lines;
• and
• forming source/drain regions in the semiconductor substrate between the word lines.