An adjustable work function technology using Mo gate for CMOSdevices

Nitrogen implantation of Mo gate was used to fabricate MOS capacitors and CMOS transistors. Initial studies demonstrate that the work function of Mo is sensitive to nitrogen implantation energy. Mo with (110) orientation exhibits a high work function, making it suitable for bulk p-MOSFET gate electrodes. Nitrogen implantation can be used to lower the Mo work function, making it suitable for n-MOSFET gate electrodes. A gate work function reduction of 0.42 eV was achieved for the n-FETs on CMOS wafers. With further optimization, this single metal gate technology may potentially replace conventional poly-Si gate technology for CMOS and can also be used for multiple-V_T technologies