Probing the dopant profile in nanoscale devices by low temperature electrostatic force microscopy

Probing dopant distributions in nanoscale devices may find important applications in failure analysis. In this work, we employed cryogenic electrostatic force microscopy (EFM) to probe the dopant distribution in a lateral nanoscale bipolar junction transistor formed by ion implantations. The photocurrent characteristics under light illumination show that the devices were made properly. The distributions of phosphorus and boron dopants are visible in the phase domain of EFM when the operating temperature is lowered to 130 K from room temperature. Numerical simulations show that the phase shifts for the doping regions are largely consistent with the experimental data.