Mapping of dopant concentration in a GaAs semiconductor by off-axis phase-shifting electron holography

This letter presents a method to map dopant concentration in compound semiconductors by off-axis electron holography. Using the microsampling technique of a focused ion beam, the authors prepared a cross sectional test specimen with n+(3.0×1018cm−3), n−(1.3×1016cm−3), and p gallium arsenide thin films. A phase map was obtained by off-axis phase-shifting electron holography, and the dopant distributions across a p-n junction are clearly observed. Furthermore, the low and high dopant concentration regions are remarkably distinguished in high contrast.

[1]  Ian Farrer,et al.  Improvement in electron holographic phase images of focused-ion-beam-milled GaAs and Si p-n junctions by in situ annealing , 2006 .

[2]  Vanzi,et al.  Electron holographic observations of the electrostatic field associated with thin reverse-biased p-n junctions. , 1985, Physical review letters.

[3]  P. Midgley,et al.  Electron holography of doped semiconductors: when does it work and is it quantitative? , 2005 .

[4]  A. Tonomura,et al.  Phase‐shifting electron holography by beam tilting , 1991 .

[5]  P. Midgley,et al.  Quantitative electron holography of biased semiconductor devices. , 2002 .

[6]  Y. Sugiyama,et al.  A study of the damage on FIB-prepared TEM samples of AlxGa1-xAs. , 2004, Journal of electron microscopy.

[7]  K. Sasaki,et al.  Surface damage induced by focused-ion-beam milling in a Si/Si p–n junction cross-sectional specimen , 2005 .

[8]  Yamamoto,et al.  High precision phase-shifting electron holography , 2001, Journal of electron microscopy.

[9]  T. Saitoh,et al.  Specimen preparation for high-resolution transmission electron microscopy using focused ion beam and Ar ion milling. , 2004, Journal of Electron Microscopy.

[10]  David J. Smith,et al.  Direct observation of potential distribution across Si/Si p-n junctions using off-axis electron holography , 1994 .

[11]  I. Lindau,et al.  New and unified model for Schottky barrier and III–V insulator interface states formation , 1979 .

[12]  Peter Schwander,et al.  TWO-DIMENSIONAL MAPPING OF THE ELECTROSTATIC POTENTIAL IN TRANSISTORS BY ELECTRON HOLOGRAPHY , 1999 .

[13]  K. Sasaki,et al.  Electron holographic characterization of electrostatic potential distributions in a transistor sample fabricated by focused ion beam , 2002 .

[14]  N. I. Kato,et al.  A PLASMA-POLYMERIZED PROTECTIVE FILM FOR TRANSMISSION ELECTRON MICROSCOPY SPECIMEN PREPARATION BY FOCUSED ION BEAM ETCHING , 1998 .

[15]  K. Sasaki,et al.  Characterizing an implanted Si/Si p–n junction with lower doping level by combined electron holography and focused-ion-beam milling , 2002 .

[16]  W. Mönch.  Chemisorption-induced defects at interfaces on compound semiconductors , 1983 .