Semiconductor devices and methods for fabricating the same

A method for forming a semiconductor device, comprising:

• providing a substrate with a well region therein;
• forming a gate stack over a portion of the well region in the memory cell and core areas, respectively, wherein the gate stack comprises an overlying gate conductor and an underlying gate dielectric;
• masking the core area by a first patterned resist layer, exposing the memory area;
• forming a lightly-doped drain (LDD) region and a deelply-doped drain (DDD) region on portions the well region exposed by the gate stack in the memory cell area;
• removing the first patterned resist layer and masking portions of the memory cell area by a second patterned resist layer, exposing a portion of the well region adjacent to a drain side of the gate stack in the memory cell area and both sides of the gate stack in the core area;
• forming a lightly-doped drain (LDD) region and a pocket region in the well region exposed by the gate stacks in the core area and the memory cell area, wherein the pocket region is formed by implanting dopants of the first conductivity type with a concentration of about 1×1018-1×1020 atoms/cm3 at an angle to the surface of the well region using the second patterned resist layer as an implant mask;
• removing the second patterned resist layer;
• forming spacers on opposing sidewalls of each of the gate stack in the memory cell and core areas;
• and
• forming a source/drain region in the well region at opposing sides of the well region exposed by the gate stacks and the spacers in the core and memory cell areas, wherein the source/drain region is formed with second conductivity type different from the first conductivity type;
• wherein the gate stack in the core area is formed with a source/drain region having a lightly-doped source/drain region adjacent thereto in the well region on opposing sides thereof and the gate stack in the memory area is formed with a source/drain region with a lightly-doped source/drain region in the well region adjacent thereto and further a pocket doping region adjacent to the lightly-doped source/drain region at a drain side.