Ballistic-electron-emission-spectroscopy detection of monolayer thickness fluctuations in a semiconductor heterostructure
12 July 1999
Ballistic-electron-emission spectroscopy (BEES) is used to measure fluctuations in the thickness of buried Ga0.8Al0.2As layers. The device under measurement is a half-electron-wavelength Fabry-Perot filter that has been designed to have two quasibound states. By performing BEES at several different spatial locations and by utilizing the relationship between the thicknesses of the device layers and the location (in energy) of the quasibound states, single-monolayer variations are detected in the thicknesses of both the GaAs quantum well and the surrounding Ga0.8Al0.2As barriers. The lateral resolution is shown to be better than 20 nm. (C) 1999 American Institute of Physics. {[}S0003-6951(99)04128-5].