The vertical test structure for measuring contact resistance between two kinds of metal

A vertical test structure was developed for measuring the contact resistance between two kinds of metal. The contact resistance between Al/TiN/AlSi and heavily As/sup +/-doped n/sup +/-poly Si was measured using this structure. The test structure was found to suppress nonuniform current density in the contact hole and to provide more accurate contact resistances. In addition, the R/sub c/ of a small contact window could be obtained from the extrapolation of the measurement data found for large contact windows.<>