Current crowding effect on thermal characteristics of Ni/doped-Si contacts

Continuous scaling of integrated circuit elements results in an increase of current density and associated Joule heating in the interconnects. The self-heating effect that leads to a temperature rise at interconnects may become a source of thermal reliability problems. This work reports an experimental and computational investigation of the current crowding effect on thermal characteristics of metal/doped-Si contacts. The temperature rise at the contacts is determined from the Seebeck potential measured in a microfabricated test structure. It is found that a nonuniform current distribution introduces a much higher heating power density than a uniform one at the contact window. The increase of the contact temperature is proportional to the power density at the Ni/doped-Si contact. The dependence of sheet resistance of the doped-Si layer, contact resistivity, and contact size on the contact power density is also discussed.