Local measurement of semiconductor band bending and surface charge using Kelvin probe force microscopy

We report on a direct local measurement of surface charge and band bending in semiconductors using Kelvin probe force microscopy. The method is based on cross-sectional surface potential measurements of asymmetric p++n or n++p junctions. A two-dimensional analysis of the junction, combined with a three-dimensional analysis of the tip-sample electrostatic interaction gives surface band bending of 0.32 eV and charge density of 8.63 × 1010 q cm−2 (where q is the elementary charge) on the surface (1 1 0) of air cleaved Si.