FACTORS AFFECTING 2-DIMENSIONAL DOPANT PROFILES OBTAINED BY TRANSMISSION ELECTRON-MICROSCOPY OF ETCHED P-N-JUNCTIONS IN SI

Transmission electron microscopy (TEM) was used to characterize image contrast obtained from doping-dependent etching of p-n junctions in si licon. The local variations in crystal thickness give rise to the appe arance of thickness fringes which may be interpreted as two-dimensiona l iso-concentration contours that map the dopant distribution. The sam ples used for the study consisted of solid source diffusions of boron into substrates of varying resistivities of both n- and p-type. The fa ctors which affect the interpretation of dopant profiles obtained from selective chemical etching of cross section TEM samples is addressed. One-dimensional chemical dopant concentration data were derived from secondary ion mass spectroscopy and one-dimensional carrier concentrat ion data were derived from spreading resistance profiling. (C) 1998 Am erican Vacuum Society.