Grain Boundary Diffusion of Copper in Tantalum Nitride Thin Films

Abstract

This work investigates the temperature and composition dependencies of Cu diffusion in tantalum nitride (TaN x) thin films. This study also measured the concentration profile of Cu using Auger electron spectroscopy. Also investigated herein are the morphology and the crystalline microstructure of tantalum nitride films using atomic force microscopy, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction, respectively. Lattice and grain boundary diffusivities were extracted from the concentration profile using the Whipple analysis of grain boundary diffusion, after annealing samples at temperatures between 500 and 800ЊC. Analysis results indicated that the Whipple model correlates well with experimental results.

Deposition of TiN and TaN by Remote Plasma ALD for Cu and Li Diffusion Barrier Applications

“…Variation of Cu sheet resistance with anneal temperature is known to provide a good measure of barrier performance. 14,22,29,30 Barrier failure leads to a significant change in resistivity due to the formation of poorly conductive Cu 3 Si, 14,20,22,29 which will result in an increase in the sheet resistance due to the concurrent loss of Cu. As a reference, the sheet resistance of a barrier-Si stack was also measured to find possible annealing effects and to investigate the thermal stability of the barrier material itself.…”

Fabrication of potential NiMoP diffusion barrier/seed layers for Cu interconnects via electroless deposition

“…In addition, both the barrier function against Cu and thermal stability of NiMoP can be verified. The diffusion depth of Cu in this case is about a range comparable to that in conventional TaN barrier at 400°C, 30 in which the diffusion coefficient of Cu is about 10 Ϫ15 cm 2 /s. Conclusively, NiMoP is a possible candidate to be an alternative choice for the TaN barrier/Cu seed couple.…”

Etching characteristics of TaN thin film using an inductively coupled plasma

“…Metal nitrides, such as TaN, TiN and WN, have recently been studied as potential diffusion barrier layer materials and research into high-k and low-k materials is ongoing. TaN can be used as a good diffusion barrier layer for metal (Cu)/high-k insulator stacks and metal (Cu)/low-k insulator stacks, due to its favorable characteristics, such as its high melting point and hardness, mechanical stability and good conductivity [4][5][6][7][8]. Moreover, for gate stacks with an HfO 2 insulator layer, the properties of the equivalent oxide thickness (EOT) can be improved by using a TaN/HfO 2 stack to replace the poly-Si/SiO 2 stack [1,[9][10][11][12][13].…”