Two-dimensional dopant profiling in shallow junctions using TEM and scanning capacitance microscopy

TEM and scanning capacitance microscopy (SCM) were used to assess two-dimensional (2D) dopant profiles in MOSFETs with source/drain where arsenic implantation was performed for various conditions, i.e., energy ranging from 35 to 100 keV As+ with doses of 2x10(13) and 1x10(14) cm(-2). As for TEM, major technique is based on the selective chemical etching of doped regions in silicon using a solution of HF and HNO3. This etching results in the local variations in crystal thickness giving rise to the appearance of thickness fringes. Such fringes could be interpreted as 2D isoconcentration contours that map the dopant distribution. Thickness fringes corresponding to a concentration of similar to 10(16) cm(-3) could be observed with accuracy better than 5 nm. The results are compared with SCM results and simulation data provided by SUPEREM-IV.