Current Crowding in Nested and Self-aligned Micrometric Contacts

A comparison between interfacial contact resistance (Ri) and End Resistance (Re) on n⁺ nested and self-aligned contacts metallized with two different schemes: Al-1% Si and Ti/TiN/Al-Si is presented. The quite different values of Ri and Re on the contacts with Ti TiN/Al-Si have been explained according to the considerable current crowding phenomenon which occurs when the tranfer length ´´lt´´ of the contact (defined by the transmission line model) is much shorter than the contact linear dimension.