Scanning spreading resistance microscopy and spectroscopy for routine and quantitative two-dimensional carrier profiling

Abstract

As emphasized in the International Technological Roadmap for Semiconductors (ITRS), two-dimensional carrier profiling is one of the key elements in support of technology development. Scanning spreading resistance microscopy (SSRM) has been demonstrated to have attractive concentration sensitivity, an easy quantification, and is applicable to complementary metal–oxide–semiconductor Si and InP structures. Its commercial implementation and availability together with an ample supply of appropriate (diamond based) tips has enabled its more widespread use during recent years. In this article we propose a number of measurement procedures and software tools for its more reliable and fast routine application. First we present a program for the automatic generation of calibration curves and the fast quantification of one-dimensional and two-dimensional resistivity (and carrier) profiles. In view of the large tip consumption, a fast evaluation and calibration of newly mounted conductive tips is a major issue. Furthermore, the fast extraction of the underlying carrier distributions leads to an easier data interpretation. We also propose an overview of the implementation and of the applications of the scanning spreading resistance spectroscopy (SSRS), where a full I–V curve is collected at each measurement point. SSRS proves to be particularly interesting to study the point-contact characteristics (in scanning mode) and simplifies significantly the junction delineation. SSRS can also be used for the selection of the optimal bias settings for the quantification procedure.