Paper TF1-MoM4
Low Temperature Dielectric ALD with the use of Hydrogen Peroxide: Comparison of Growth and Film Characteristics for Anhydrous H₂O₂, H₂O₂/H₂O Mixtures and H₂O

Monday, October 22, 2018, 9:20 am, Room 102A

Novel precursor chemistries are being sought for ALD of dielectrics, where a tremendous amount of effort has been put into development of new Organometallic and Organosilicon precursors. Our approach focuses on providing a novel oxidant that may improve the reactivity of precursors that react slowly or incompletely with water. Our approach entails the development of two hydrogen peroxide gas delivery systems:

• An ampoule based formulation for anhydrous hydrogen peroxide, where H₂O₂ is delivered in the gas phase in the absence of water by use of a membrane delivery system.
• A gas generator approach, where a high concentration H₂O₂/H₂O mixture is delivered by in situ concentration methods and the use of a membrane vaporizer.

Anhydrous Hydrogen Peroxide Gas

Initial ALD results for growth of ZrO₂ from anhydrous H₂O₂ and CpZr(N(CH₃)₂)₃ show high quality film growth at 260C. A linear growth curve is observed with minimal saturation delay. ZrO₂composition was characterized by XPS and XRR, with results very similar to films grown with ozone. In addition, films resulting from H₂O₂ ALD were placed into MIMCAP structures. These structures show high k values of 35, slightly improved over those grown with a 20% ozone concentration at 32.

High Concentration Hydrogen Peroxide Gas

A novel gas generator for delivery of H₂O₂/H₂Omixtures has been developed. This equipment utilizes a carrier gas and delivers up to 5% H₂O₂/21% H₂O gas by volume from 30wt% H₂O₂ liquid solution (H₂O/H₂O₂=4.2). This gas mixture enables lower-temperature growth processes vs water, where HfO₂ films may be grown at temperatures as low as 100C.

Our current focus is on low temperature growth of SiO₂ ALD. Reactions of tris(dimethylaminosilane) (N(CH₃)₂)₃SiH were performed with H₂O₂. Film characterization for anhydrous H₂O₂, H₂O mixtures, and water will be compared for films growth at 300C. Wet etch rates and refractive index will also be reported. Applications for multiple pattern spacers and hardmasks will also be discussed.