Secondary electron dopant contrast imaging of compound semiconductor junctions

Abstract

Secondary electron imaging combined with immersion lens and through-the-lens detection has been used to analyze various semiconductor junctions. Dopant contrast imaging was applied for multi-doped 4H-SiC, growth-interrupted n þ /p and n/n þ homoepitaxial interfaces, and an AlGaAs/ GaAs p-n junction light-emitting diode structure. Dopant contrast was explained by the local variation in secondary electron escape energies resulting from the built-in potential difference. The effect of varying electron affinity on contrast for the heterostructures is also discussed. The contrast profile of the n-doped AlGaAs compared reasonably well to the simulated valence bandedge energy using a previously determined efficiency of dopant ionization.

High resolution SEM characterization of nano‐precipitates in ODS steels

“…Conducted procedure requires less effort in sample preparation and usually each process ends with success. Advanced optics and detection system of modern HR‐SEM devices allows collecting images not only with topography of the sample, but also with much more information about various properties of the specimen itself (Chung et al, ; El‐Gomati & Walker, ; Morandi, Merli, & Ferroni, ; Pratt, Matthew, El‐Gomati, & Tear, ; Schonjahn, Humphreys, & Glick, ). Especially the availability of the low‐energy of the primary electrons opens new chapters in characterization of the multi‐phase materials (El‐Gomati & Wells, ; Grodecki, Jozwik, Baranowski, Teklinska, & Strupinski, ; Hiura, Miyazaki, & Tsukagoshi, ; Kochat et al, ; Mullerova, ; Muray, ; Nagoshi, Aoyama, & Sato, ; Park, Kim, & Yang, ; Zhou et al, ).…”

Epitaxial Growth of Silicon Carbide

“…Because the two partial dislocations and the Shockley-type stacking fault between them cannot be directly deflected to the c-axis, it is supposed that the two partial dislocations must merge into a perfect BPD (b = <1120>∕3) before conversion to a TED. This has recently been confirmed by three-dimensional synchrotron X-ray topography analyses [121] and a careful TEM study [122]. Conversion from BPDs to TEDs is enhanced by several techniques, such as molten KOH etching [123][124][125] or H 2 etching [126] prior to epitaxial growth or interruption during growth [127].…”

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

“…Various studies on quantitative dopant mapping in semiconductors using low landing energy electrons have been reported recently where the doping information is obtained by extracting contrast directly from a SE image (Frank et al, 2006; Mika & Frank 2008; Tsurumi et al, 2010; Chung et al, 2011; Tsurumi et al, 2012). However this is not an accurate method since the conventional SE detector captures a bulk signal formed from electrons that leave the specimen over a wide range of different energies and angles, making the output signal dependent on a number of different parameters other than dopant concentration levels in the specimen (Oatley, 1966; Reimer, 2000; Goldstein et al, 2003; Frank et al, 2007).…”