Specific contact resistivity of metal-semiconductor contacts-a new, accurate method linked to spreading resistance

A method to determine the specific contact resistivity of metal-semiconductor contacts has been developed. It allows the separation of the total series resistance between two contacts into the contributing component resistances. The principle of the method is the subtraction of the semiconductor spreading resistance from the total two-contact resistance. This requires geometrically well-defined small contacts that are fabricated precisely by lithographic methods. Using this method, accurate values were obtained for the specific contract resistivity of an aluminium-1.5% silicon alloy to p-type silicon wafers having dopant densities from 5×10¹⁴ to 2×10²⁰ cm^-3. The specific contact resistivity values are lower than previously published values obtained using earlier methods in which parasitic and nonideal effects could not be quantified or eliminated. The lower values indicate that contact resistance has a less-limiting effect on the performance of integrated circuits than presently believed