Photon energy dependence of contrast in photoelectron emission microscopy of Si devices
Contributors: V.W. Ballarotto, K. Siergrist, R.J. Phaneuf, E.D. Williams, W.-C. Yang, and Robert J. Nemanich
ABSTRACT
We investigate the variation in doping-induced contrast with photon energy in photoelectron emission microscopy images of Si pn devices using a free-electron laser as a tunable monochromatic light source. Photoyield is observed from p-doped regions of the devices for photon energies as low as 4.5 eV. Band tailing is the dominant effect contributing to the low energy photoyield from the heavily doped p regions. The low intensity tail from the 𝑛 regions, however, may be from surface states.