Atomic-layer deposition of ZrO2 with a Si nitride barrier layer

ZrO2 thin films for gate dielectrics have been formed at low temperatures (200 degreesC) by an atomic-layer deposition (ALD) technique using Zr(t-OC4H9)(4) and H2O source gases. An ultrathin (physical thickness T-phy of similar to0.5 nm) Si nitride layer was deposited on a Si substrate by ALD before the deposition of ZrO2. Transmission electron microscopy showed that the Si nitride barrier layer successfully suppressed the formation of a SiO2 interfacial layer. Because of the extremely uniform thickness control capability in the ultrathin region and the low thermal budget of the ALD process, the ALD process for the ZrO2/Si nitride stack structure is a promising candidate for fabricating the ultrathin gate dielectrics for sub-0.1-mum complementary metal-oxide-semiconductor transistors. (C) 2002 American Institute of Physics.