Stress memorization technique (SMT) by selectively strained-nitride capping for sub-65nm high-performance strained-Si device application

An advanced stress memorization technique (SMT) for device performance enhancement is presented. A high-tensile nitride layer is selectively deposited on the n+ poly-Si gate electrode as a stressor with poly amorphorization implantation in advance. And, this high-tensile nitride capping layer will be removed after the poly and S/D activation procedures. The stress modulation effect was found to be enhanced and memorized to affect the channel stress underneath the re-crystallized poly-Si gate electrode after this nitride layer removal. More than 15% current drivability improvement was obtained on NMOS without any cost of PMOS degradation. Combining the high tensile nitride sealing layer deposition after silicide process. it was found to gain additional ∼10% improvement to NMOS. The device integrity and reliability were verified with no deterioration by this simple and compatible SMT process. which is a promising local strain approach for sub-65nm CMOS application.