Compositional analysis of submicron silicon in one, two and three dimensions

Shrinking VLSI geometries have resulted in increasingly non-planar structures and current flows, necessitating lateral as well as vertical information on dopant distribution for device design, modelling and optimisation. Continuing demand for improved vertical resolution (1-10nm) has led to improvements in existing 1D dopant profiling techniques: new 2D techniques of reasonable resolution (20-25nm) are beginning to meet the demand for lateral information; 3D techniques at present are too low in resolution (0.5 micron) or sensitivity (10²⁰/cc). The present status of dimensional compositional analysis techniques as applied to VLSI submicron structures is reviewed.