Two-dimensional carrier profiling of InP structures using scanning spreading resistance microscopy

Abstract

Scanning spreading resistance microscopy (SSRM) is an analytical technique originally developed for measuring two-dimensional carrier distribution in Si device structures with high spatial resolution. It is in essence an atomic force microscope equipped with a conducting tip that is biased relative to the sample. The spreading resistance value derived from the measured electrical current is a function of the local carrier concentration at the surface region surrounding the probe’s tip. In this letter, we report the successful application of SSRM to the analysis of InP semiconductor device structures. We imaged a multilayer epitest structure, and a cross section of a three-dimensional structure in which we observed lateral Zn-dopant diffusion. Comparison of the SSRM profiles with one-dimensional secondary ion mass spectrometry depth profiles shows good qualitative agreement. SSRM analysis of InP-based device structures was found to be much simpler than that of Si structures: there is no need for surface preparation of the cleaved surface, a lower tip force is required, and metal tips, rather than doped diamond can be used.

Wet Etching Study of La0.67(Sr0.5Ca0.5)0.33MnO3 Films on Silicon Substrates

“…17,18 Using an electrically conductive probe in contact mode, the electrical resistance is obtained by measuring the voltage. The local resistivity of the films can be calculated by using the following relation:…”

“…17,19 We performed this measurement on the LSCMO films in order to determine the local resistivity before and after KOH etching. During the measurement, an initial low DC voltage was applied to prevent the etched thin-free standing membrane of LSCMO layer from collapsing after the KOH etching.…”

Characterization of conductive probes for atomic force microscopy

“…Accelerated tip-deformation was obser\ed by SEM after the experiments. However, these probes hae been used successfully for SSRM on lnP [21] and SCM on various substrates. Very fiw of the tested pyramidal diamond probes could be used for Nanopotentiometry and SSRM on Si despite their apparent excellent conductivity combined with the higher hardness of the probe material.…”

Scanning spreading resistance microscopy for failure analysis of nLDMOS devices with decreased breakdown voltage

“…First applications of the technique were reported in 1998 [1,2]. SSRM is a secondary imaging mode derived from contact Atomic Force Microscopy (AFM).…”