Failure analysis for NMOS missing LDD/pocket by nanoprobing and STEM-EDS techniques to advanced nano-devices

This paper mainly demonstrated the fail NMOS suffered lightly doped drain (LDD) & pocket (PK) implantation issue, suspect this loop defects induce the NMOS LDD&PK asymmetry partial missing. Device failure site was located by nano-probing. Based on electrical results, TEM energy-dispersive x-ray spectroscopy (EDX) images obtained from a cross-section, prepared at the designated location, showed n-type (As) missing at LDD area. The technology computer-aided design (TCAD) simulation verified the nano-probing data and the PK profile, and confirmed the failure model. Meanwhile, the EDX, nano-probing and TCAD technologies were proven to be promising techniques for analyzing the two dimensional dopant profile of advanced nanometer-scale MOS device.