Nanometer-resolved spatial variations in the Schottky barrier height of a Au/n-type GaAs diode

Abstract

Nanometer-resolved lateral variations in the Schottky barrier height (SBH) formed at a chemically prepared Au/n-type GaAs interface were measured using ballistic-electron-emission microscopy (BEEM). The spatial profile and the statistical distribution of the SBH's thus obtained were compared to current-voltage (IV) and capacitance-voltage {CV) characteristics of the same metal-semiconductor contact. This comparison showed that the macroscopic SBH obtained from the IV measurements can be successfully interpreted using the parallel conduction model applied to the BEEM-derived distribution, if the effect of thermionic field emission is included. The SBH obtained from the CV measurements is greater than the mean value obtained from BEEM measurements by nearly the image-force lowerin expected for a Au/GaAs diode.

Mapping of AlxGa1−xAs band edges by ballistic electron emission spectroscopy

“…Each error bar is the result of 20 to 30 local measurements. The size of the error bar ranges from 30 to 50 meV, which is comparable with the local variation of Au/GaAs Schottky barrier height obtained by Williams et al 21 Tip drift limited our spectroscopy resolution to about 5-10 nm, which is an order of magnitude higher than the theoretical limit. This may have resulted in less measured variation since BEEM spectroscopy was averaged over a larger area.…”

Electron transport measurements of Schottky barrier inhomogeneities

“…Recently, ballistic electron emission microscopy ͑BEEM͒ techniques demonstrated that nanoscale inhomogeneities give rise to nonideal macroscopic behavior in the I -V characteristics of a diode. [3][4][5][6][7] The scanning tunneling microscope in these experiments, however, allows only very small contact areas to be probed. In this letter, we investigate transport through the Schottky barrier of PtSi/Si contacts by examining the lowtemperature current versus gate voltage (I -V g ) characteristics in Schottky-barrier metal-oxide-semiconductor fieldeffect transistors ͑SBMOSETs͒.…”

Investigation of special features of parameters of Schottky barrier contacts caused by a nonlinear bias dependence of the barrier height

“…It is confirmed by direct studies of the distribution of the barrier height in contacts with ballistic electron emission microscopy (a BEEM-method). 16 However, studies [17][18][19][20][21][22][23][24] (and others) evidently do not indicate that the "saddle points" play the main role in the observed "anomalies" in the contact characteristics, but do not exclude other factors playing a similar role. It should also be noted that for comparison with experiment, a highly simplified version of the model of "saddle points" with the IVC significantly different from the exact expression 25 (Eq.…”