Simultaneous measurement of potential and dopant atom distributions on wet-prepared Si(111):H surfaces by scanning tunneling microscopy

Abstract

The authors demonstrate the ability of scanning tunneling microscopy and spectroscopy to simultaneously measure the distributions of both the surface potential and the individual dopant atoms on the atomically flat hydrogen-terminated Si(111) surfaces prepared by an aqueous NH4F etching without disturbing the original dopant distribution. At the p-n junctions, the acceptor and donor atoms were detected distinctly, and the variation in the observed height reflected the surface potential under the biasing condition. Further, a strong correlation between the dopant fluctuations and the surface potential distributions was identified.

3D modeling based on current continuity for STM carrier profiling of semiconductor devices

“…Previously, we have reported on observation of boron and arsenic dopant atoms in Si under different bias voltages as shown in fig.11 [3]. The white arrows in the figure indicate boron ions which are observed bright in (a) V sub < 0 and dark in (b) V sub > 0.…”

“…Carrier distribution is deduced from change in STM IV-curves depending on the measured points. STM can detect individual dopant atoms locating just beneath the surface [3].…”

“…Profiling of device cross sections by scanning tunneling microscopy (STM) has been studied already [1][2] [3]. Fig.1 shows an example of STM measurement across a p-n junction.…”

Three-dimensional simulation of scanning tunneling microscopy for semiconductor carrier and impurity profiling

“…[5][6][7][8] Among several approaches, we have focused on scanning tunneling microscopy (STM) and developed a metrology for 2D impurity profile extraction from the surfaces of semiconductor samples. 9 As reported in Ref. 9, we have succeeded in extracting the impurity profile from the surface potential of semiconductor samples.…”

“…9 As reported in Ref. 9, we have succeeded in extracting the impurity profile from the surface potential of semiconductor samples. Furthermore, through high-accuracy scanning, we have confirmed that the positions of each discrete dopant ion can be observed by STM measurements, which is an advancement of the method.…”