W as a bit line interconnection in capacitor-over-bit-line (COB) structured dynamic random access memory (DRAM) and feasible diffusion barrier layer

In this paper, we discuss the formation of a TiN/TiSi2 bilayer from TiNx and its utilization as a diffusion barrier for the W bit-line process in COB structured DRAM devices. Since the TiSi2 layer formed on a Si substrate is very thin and uniform, the TiNx-contacted n(-) and n(+) junction showed desirable electrical properties. The compact structure of the overlying TiN due to its lack of grain boundary voiding enabled the TiNx to be used as a diffusion barrier for the W bit line process.