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

摘要

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+(3.0X 10~(18) cm~(-3)), n-(1.3 X 10~(16) cm~(-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.