Image contrast of impurity regions of semiconductor crystals in scanning electron microscopy

Abstract

A critical survey of the current state of the problem of visualizing local impurity regions of semi conductor crystals in a scanning electron microscope (SEM) is presented. A new physicotechnical solution for monitoring impurity distributions in doped regions that allows us to increase the contrast between images of impurity sectors in a wide range of concentrations is proposed.

Optimized dopant imaging for GaN by a scanning electron microscopy

“…Both the CV number and visual inspection reveal that combining low V acc and/or low WD yields better doping contrast (Figure 4, green box), and vice versa. The doping contrast strongly depends on both V acc and WD: it decreases with increasing V acc 49,50 and WD. 28 For example, at a WD of 3 mm, as V acc increased from 1 to 10 kV, CV decreased sharply from 9.9 to 1.8; at a V acc of 2 kV, as the WD increased from 3 to 8 mm, the CV decreased from 6.7 to 1.3.…”

Voltage and Dopant Concentration Measurements of Semiconductors using a Band-Pass Toroidal Energy Analyzer Inside a Scanning Electron Microscope

“…The use of a toroidal band-pass energy analyzer attachment for the SEM was reported by Rau and Robinson (1996), and has for the most part been used to acquire BSE spectra. Recently Rau & Tagachenkov (2013) reported its use for acquiring SE spectra, but did not give any quantitative analysis on its signal to noise characteristics. The Rau and Robinson toroidal analyzer has first-order focusing charcteristics and requires multi-channel detection in the azimuthal angular direction.…”