Multi-spot model showing the effects of nano-spot sizes

A multi-spot stochastic model is developed to calculate the resistance of degraded contacts. Variables such as number and size of contact spots, and thickness and resistivity of oxide films are varied randomly to simulate the impact on contact resistance. In addition, the effects of small contact spots are estimated using the Sharvin and Wexler equations for cases where the Knudsen ratio is small (where the size of a contact spot approaches or falls below the collision mean free path of electrons). The results are used to show the statistical variations in contact resistance due to random variations in film characteristics. Test data are provided as a comparison to the model predictions and are used to validate the model results.