Towards sub-10 nm carrier profiling with spreading resistance techniques

The manufacturing of state-of-the-art electronic devices involves an increa sing demand for the accurate determination of ultra-shallow electrical carr ier profiles related to the need to monitor the activation of the dopants w ith reduced thermal budgets. For sub-micron structures (down to 100nm) a qu alified conventional spreading resistance probe system is an attractive too l for the reliable measurement of the resistivity land carrier) depth varia tions in silicon due to its high geometrical resolution (nm) and high dynam ic range (nine orders of magnitude). The spreading resistance (SR) roadmap for future process development (sub-50 nm profiles), however, shows that th ere is a need for a significant reduction of the involved contact size and tip separation, a higher depth resolution (sub-nm) and an improved quantifi cation. The recently introduced scanning spreading resistance microscopy te chnique resolves some of the involved issues such as the smaller contact si ze (20-50 nm) and the higher geometrical depth resolution (sub-nm) when app lied on a bevelled surface. Further developments are, however, needed in th e fields of tip configuration, surface preparation and contact modelling to achieve timely all the needs of the SR roadmap. This is expected to lead t o a new instrument, the NanoProfiler(TM), using two small (20-50 nm contact size), closely spaced (250 nm): conductive tips mounted on an atomic force microscope-based system. The NanoProfiler(TM) setup can easily achieve Ang strom depth resolution and therefore makes the profiling of sub-10 nm struc tures feasible. (C) 2001 Elsevier Science Ltd. All rights reserved.