Product Wafer Monitoring of Ultra-Shallow Channel Implants with an Elastic Metal Gate (EM-gate)

The most critical parameter for deep submicron metal–oxide–semiconductor (MOS) field effect transistors (MOSFETs) is the threshold voltage (VT). The device VT is highly dependent on processing; specifically, the ion implanted channel-doping profile. Monitoring the channel doping on product wafers is highly desirable and is a major issue for process engineers. A technique based on a noncontaminating, nondamaging, small diameter metal contact is described for highly sensitive and precise measurements of the channel carrier density profile, dose and VT on product wafers.