Scanning capacitance microscopy measurement of two-dimensional dopant profiles across junctions

Cross-sectioned p+/p and p–n junction test structures were imaged with a scanning capacitance microscope (SCM). To maintain a constant difference capacitance, our SCM utilizes an electronic attenuator circuit with a dynamic range of 20 V to less than 1 mV. Dopant profiles are extracted from SCM images using a formalism, which rapidly determines the theoretical SCM response from a database of calculated C–V curves. A dopant profile from a p+/p junction determined via constant difference capacitance SCM is compared to a secondary ion mass spectroscopy profile from similar structures.