Patent ID: 9184170
Filing Date: 2015-11-10
Classification: H01L

Abstract:
1. A method of forming a semiconductor device, the method comprising: providing a front-end device having a plurality of memory cells, each memory cell including at least two pull-up transistors, at least two pull-down transistors, and at least two pass-gate transistors, the pull-up transistors, the pull-down transistors, and the two pass-gate transistors each having a gate and gate sidewalls; forming a mask over the at least two pull-up transistors; performing a first lightly doped source and drain ion implantation at a first tilted angle into the at least two pull-down transistors and the at least two pass-gate transistors; and performing a second lightly doped source and drain ion implantation at a second tilted angle into a portion of the at least two pull-down transistors and the at least two pass-gate transistors; wherein the first tilt angle and the second tilt angle are angles relative to a direction perpendicular to a surface of the front-end device, and the first tilt angle is smaller than the second tilt angle.