Delineation of semiconductor doping by scanning resistance microscopy

Abstract

Coupling scanning tunneling microscope and supersonic molecular beams: A unique tool for in situ investigation of the morphology of activated systems Rev. Sci. Instrum. 83, 093703 (2012) Inelastic tunneling spectroscopy of gold-thiol and gold-thiolate interfaces in molecular junctions: The role of hydrogen J. Chem. Phys. 137, 094703 (2012) Scanning tunneling microscopy/spectroscopy studies of resistive switching in Nb-doped SrTiO3 J. Appl. Phys. 112, 023703 (2012) Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips Rev. Sci. Instrum. 83, 063708 (2012) c(4×2) and related structural units on the SrTiO3(001) surface: Scanning tunneling microscopy, density functional theory, and atomic structure

Doping profile effects on modulation-doped single nonabrupt GaAs/AlxGa1−xAs quantum wells

“…Our numerical calculations showed that the existence of inhomogeneous doping can strongly modify the electronic properties of doped quantum wells, being at least as important as nonabrupt interface effects. Despite limitations on the knowledge of Si diffusion in GaAs and Al x Ga 1−x As [16], and the limited spatial resolution (∼30 nm) achieved nowadays by the experimental methods used to probe dopant profiles [4][5][6][7], we believe that future experiments on inhomogeneous doping characterization and on the electron intersubband transitions in inhomogeneous doped single nonabrupt GaAs/Al x Ga 1−x As quantum wells will validate the assumptions of our inhomogeneous doping model and confirm our main results.…”

“…Following indications of experimental results concerning inhomogeneous doping patterns [4][5][6][7], we described the inhomogeneous Si-doping concentration profile N D (z) in the growth direction z by the following expression:…”

“…Previous investigations have addressed mainly the ideal semiconductor interfaces (abrupt) and ideal doping profiles (homogeneous) pictures. However, cumulative experimental evidence indicates that GaAs/Al x Ga 1−x As interfaces are not abrupt [2,3], and that the dopant density should be inhomogeneous [4][5][6][7].…”

“…Several dopant profile measurements suggest that inhomogeneous doping patterns can be modeled by error functions, and a dopant density variation at least of 10 2 cm −3 can occur within distances of the order of 100 Å [4][5][6][7].…”

Effect of a charged scanned probe microscope tip on a subsurface electron gas

“…SPM techniques [1] have been widely used to characterize semiconductors at room temperature: capacitance [2][3][4] and resistance [5] profiling of carrier distributions have been demonstrated, and trapped charge has been deposited and observed via both force [6] and capacitance [7] microscopy. Recently we have demonstrated the use of an atomic force microscope with a conducting tip at 4.2 K to characterize ballistic electron flow through a point contact in a two-dimensional electron gas (2DEG) located beneath the surface of a GaAs/AlGaAs heterostructure [8].…”