A TESTER FOR THE CONTACT RESISTIVITY OF SELF-ALIGNED SILICIDES.

While the process of self-aligned silicide in MOS circuits is getting more and more attention, a good tester that is fully compatible with the silicide process to monitor the silicide-to-Si contact characteristics has not been available. This is because a standard Kelvin tester requires multiple contacts to one diffusion region, and for self-aligned silicide process, only one silicide contact is possible for each diffusion. In this paper a novel tester is presented which utilizes MOSFET inversion channels to connect silicided source/drain contacts electrically together to satisfy the requirements of a Kelvin tester. This tester, basically two MOSFETs back to back, can be fabricated along with real devices and requires no additional processing steps. Two versions of the Kelvin testers have been examined, the cross-bridge Kelvin resistor and the contact end resistor. The principles of these devices are explained and some measurements are demonstrated.