An Advanced High-k Transistor Utilizing Metal-Organic Precursors in an ALD Deposition of Hafnium Oxide and Hafnium Silicate with Ozone as Oxidizer

Abstract

AbstractThe International Technology Roadmap for Semiconductors (ITRS) has projected that continued scaling of planar CMOS technology to the 65nm node and beyond will require development of high-k films for transistor gate dielectric applications to allow further scaling of overall device sizes according to Moore's Law [1]. Researchers have recently been studying hafnium-based high-k dielectrics as an alternative to SiO2 [2]. The method of deposition of these films has been found to impact the applicability of the films for both low standby power and high performance applications [3]. Atomic Layer Deposition (ALD) has been among the more widely studied deposition techniques for these films, but previous work has emphasized ALD utilizing inorganic precursors [4]. In this paper, we shall describe a process in which hafnium oxide and hafnium silicate films were deposited from alternating pulses of volatile metal-organic Hf/Si liquid precursors and ozone on 200mm diameter Si substrates using a single wafer ALD system. Electrical characterization of the films is presented, including equivalent oxide thickness (EOT), gate leakage, and electron mobility data, showing an achievement of EOT's ranging from 1.19 to 1.69 nm with high field mobilities from 74% to more than 90% of that of SiO2 (2.1 nm film), and Jg in the range of 80mA to 3 A/cm2.