Silicide and Shallow Trench Isolation line width dependent stress induced junction leakage

For the first time, the influence of the mechanical stress, induced by silicidation of active areas in combination with stress from the Shallow Trench Isolation (STI), on the leakage current of n+/p and p+/n junctions has been studied. When scaling down the width of the diode structure from 2 mu m to 0.25 mu m, the anisotropic compressive stress In the junction area increases drastically. These experiments prove that regardless the contributions of the area and the perimeter to the total leakage current of this type of diode structure (approximate to 20%), 80% of the total leakage current of this diode structure can be attributed to stress and that this part of the leakage current increases with almost a factor of two when reducing the junction width from 2 mu m to 0.25 mu m. Therefore, in order to keep the diode leakage variation as low as possible when further down scaling the junction and the trench dimensions, the formation of a low stress silicide in combination with a low stress isolation technology is essential.