Deposition of High-k Dielectric Oxide Films by Liquid Injection MOCVD

Abstract

ZrO2, HfO2, La2O3 and their related silicates are candidates to replace SiO2 as the gate dielectric material for sub-0.1 μm CMOS technology, and metalorganic chemical vapour deposition (MOCVD) is an attractive technique for the deposition of these materials. However, there are problems associated with many of the existing Zr and Hf oxide precursors. In this paper, we describe the liquid injection MOCVD of ZrO2 and HfO2 using the new improved alkoxide precursors [M(OBut)2(OCMe2CH2OMe)2] and [M(OCMe2CH2OMe)4] (M = Zr, Hf). The growth of high quality La2O3 or LaSixOy films by MOCVD has also proved difficult due to a lack of suitable precursors, and in this paper we describe the use of [La[N(SiMe3)2]3] for the liquid injection MOCVD of LaSixOy, in the absence of an added Si source. High frequency C-V measurements for MOS-capacitors fabricated from ZrO2, HfO2 and LaSixOx demonstrate the feasibility of using liquid injection MOCVD to deposit MOS gate dielectric films at low process temperature.