Capacitance–voltage measurement and modeling on a nanometer scale by scanning C–V microscopy

Presently, a nanometer scale capacitance–voltage (C–V) method for the quantitative measurement of the lateral dopant distribution near a semiconductor surface is being established. An atomic force microscope is used to position a nanometer scale tip at a semiconductor surface, and local C–V measurements are performed. Experimental C–V curves have been performed with tips of sub-50 nm radius on a series of silicon wafers of known dopant density. It is shown that repeatable C–V measurements can be performed with nanometer scale tips, and that the capacitance change from accumulation to depletion varies monotonically with local dopant density. The C–V measurements are compared with the theoretical predictions of a simple analytical model. The experimental measurements will be described and the results will be discussed.