'Inside-Out' Approach for Sub-nm Resolution Carrier Profiling in Semiconductors

摘要

An 'inside-out' approach to carrier profiling is described where the external oscillator for scanning capacitance microscopy (SCM) or scanning spreading resistance microscopy (SSRM) is replaced by generating a unique microwave frequency comb (MFC) at a sub-nm spot on the semiconductor in a scanning tunneling microscope (STM). The small size of the spot is the key to possible sub-nm resolution. Each harmonic of the MFC has sub-Hz linewidth. High-speed parallel measurements of the harmonics and low noise due to the narrow linewidth may enable improved speed and accuracy. A new 'inside-out' method is also described which has the potential for greater accuracy as a nulling measurement. All three of these methods are examples of 'scanning frequency comb microscopy' (SFCM).