Nb Contacts for Thermally-stable High-performance Logic and Memory Peripheral Transistor

Abstract

Thermal annealing induced high contact resistivity (ρc) and parasitic resistance (Rparasitic) is major obstacle to realize high performance scaled logic and memory peripheral (peri) transistors. In this work, we report on the first demonstration of Niobium (Nb) as a thermally stable contact metal having a low ρc on a FinFET platform for both logic and memory peri applications. With Nb contact, we demonstrate a ~4x reduction in post DRAM anneal (600 °C, 4 hrs) contact resistivity (ρc) from a circular transmission line model (CTLM), compared to titanium (Ti). Moreover, when integrated in a transistor (FinFET), Nb exhibits a remarkable 35% decrease in the parasitic resistance (Rparasitic = Rcontact+ Repi+Rinterface), along with a 3x reduction in post DRAM anneal pc to achieve a low value of ~2.9 × 10−9 Ω-cm2.