2-DIMENSIONAL JUNCTION PROFILING BY SELECTIVE CHEMICAL ETCHING - APPLICATIONS TO ELECTRON DEVICE CHARACTERIZATION

We present recent developments of the sample preparation technique use d to obtain the delineation of a two-dimensional junction profile by t ransmission electron microscopy analysis. The technique is based on th e selective chemical etching of doped regions in silicon by a HF:HNO3 chemical mixture. The role of crystallographic defects and the influen ce of the substrate doping (n or p type) is explained by taking into a ccount the free carriers present at the solid/solution interface durin g the silicon dissolution process. This information allows us to ident ify some crucial aspects of the sample preparation method, and two-dim ensional junction profiles can also be obtained in the case of samples doped with boron. The high spatial resolution of the technique allows us to resolve several features of the doping profiles which are not d etectable with other techniques and to characterize a wide range of el ectron devices. (C) 1996 American Vacuum Society.