AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Wednesday Sessions
       Session NS-WeM

Paper NS-WeM5
Development of a Tunable Microwave Frequency Alternating Current Scanning Tunneling Microscope to Profile Dopant Density in Semiconductors

Wednesday, November 2, 2005, 9:40 am, Room 210

Session: Nanometer Scale Imaging
Presenter: A.M. Moore, The Pennsylvania State University
Authors: A.M. Moore, The Pennsylvania State University
B.A. Mantooth, GeoCenters
P.S. Weiss, The Pennsylvania State University
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We have built a scanning tunneling microscope (STM) capable of profiling dopants in semiconductor devices and test structures at sub-nanometer resolution. The alternating current signals, and thereby the dopant density and type, are obtained through a heterodyned signal. Two frequencies are applied to the STM tip and the nonlinearity of the tunnel junction mixes the frequencies, generating new signals including at the difference of the frequencies applied; this in combination with the DC bias yields information on the dopant density and type. This ultrahigh resolution (<1 nm) profiling tool enhances what is obtained through current metrology tools and will support semiconductor processing as the size scale of devices continues to decrease.