Doping landscapes in the nanometer range by scanning capacitance microscopy

In this work, scanning capacitance microscopy (SCM) is applied to image semiconductor structures wherein the designed doping variations are in the nanometer range. Two examples are presented. The first one is the study of a periodically corrugated p-i-n junction wherein the corrugation is provided by a 240 nm period, 120 nm deep grating. The nm-modulation in the depletion region is clearly detected by SCM and the lateral resolution is significantly better than the duty cycle (120 nm) of the gratings. Further, it is also seen that the presence of the gratings does not affect the dopant incorporation during growth. In the second example, the SCM is applied to image 240 nm period n + InP gratings embedded in semi-insulating InP. The SCM is indeed successful in detecting the fine period, buried gratings. Possible applications to similar systems are pointed out. (C) 1999 Elsevier Science B.V. All rights reserved.