Plasma-enhanced atomic layer deposition of tantalum nitrides using hydrogen radicals as a reducing agent

Abstract

Plasma-enhanced atomic layer deposition (PEALD) of tantalum nitride (Ta-N) thin films at a deposition temperature of 260 degreesC using hydrogen radicals as a reducing agent for tertbutylimidotris(diethylamido)tantalum is described. The PEALD yielded superior Ta-N films with an electric resistivity of 400 mu Ohm cm and no aging effect under exposure to air. The film density was higher than that of Ta-N films formed by typical ALD, in which NH3 is used instead of hydrogen radicals. In addition, the as-deposited films were not amorphous, but rather polycrystalline structures of cubic TaN. The density and crystallinity of the films increased with the pulse time of hydrogen plasma. The films were Ta-rich in composition and contain around 15 atom % of carbon impurity. (C) 2001 The Electrochemical Society.