The channel width-to-length ratio is an important transistor parameter for integrated circuit design. Contact diffusion in to the channel during fabrication or operation alters the channel width and this important parameter. A novel methodology combining atomic force microscopy and scanning Kelvin probe microscopy (SKPM) with self-consistent modelling is developed for the non-destructive detection of contact diffusion on active devices. Scans of the surface potential are modelled using physically-based Technology Computer Aided Design (TCAD) simulations when the transistor terminals are grounded and under biased conditions. The simulations also incorporate the tip geometry to investigate its effect on the measurements due to electrostatic tip-sample interactions. The method is particularly useful for semiconductor- and metal- semiconductor interfaces where the potential contrast resulting from dopant diffusion is below that usually detectable with scanning probe microscopy.
展开▼
