Extremely deep profiling analysis of the atomic composition of thick ($>$ 100 $\mu$m) GaAs layers within power PIN diodes by secondary ion mass spectrometry

A new opportunity to analyze the atomic composition of thick ($>$100 $\mu$m) epitaxial GaAs layers by SIMS with lateral imaging of the cross section of a structure is demonstrated. The standard geometry of ldepth analysis turns out to be less informative owing to material redeposition from the walls of a crater to its floor occurring when the crater depth reaches several micrometers. The profiles of concentration of doping impurities Te and Zn and concentrations of Al and major impurities in PIN diode layers are determined down to a depth of 130 $\mu$m. The element sensitivity is at the level of 10$^{16}$ at/cm$^3$ (typical for depth analysis at a TOF.SIMS-5 setup), and the resolution is twice the diameter of the probing beam of Bi ions. The possibility of enhancing the depth resolution and the element sensitivity of the proposed analysis method is discussed.