Atomic layer deposition of hafnium oxide and hafnium silicate thin films using liquid precursors and ozone

Abstract

Atomic layer deposition (ALD) processes for HfO2 and HfxSi1−xO2 high-k dielectric thin films using liquid precursors and ozone were evaluated. Tetrakis(ethylmethylamino)hafnium (TEMAHf) precursor provides HfO2 films with superior quality as compared to Hf(t-butoxide)4 precursor in terms of deposition rate, purity, and electrical properties of the films. ALD processes for hafnium silicate films have been developed by co-injection of TEMAHf and tetrakis(ethylmethylamino) silicon precursors. Alternating pulses of the Hf/Si precursor vapor mixture and ozone allow process temperatures below 400 °C to grow HfxSi1−xO2 film. The Hf and Si precursors can be converted to vapor for delivery to the deposition chamber either by bubbling an inert carrier gas separately through each liquid or by using a liquid vaporization unit. The co-injection process enables the formation of homogeneous single-layer hafnium silicate films as deposited.

Growth and phase stabilization of HfO2 thin films by ALD using novel precursors

“…Hafnium compounds belonging to the group of alkylamides, e.g. Hf(NEtMe) 4 have been widely applied with water or ozone as the oxygen source to produce HfO 2 films [8][9][10][11]. Their volatility, reactivity and resulting high growth rate of HfO 2 can be considered as clear advantages.…”

Determination of the density of the defect states in Hf0.5Zr0.5O2 high-k film Deposited by using rf-magnetron sputtering technique

“…It was reported that the electrical properties of HfO 2 can be improved by adding different elements such as N, Si, Al, Ti, Zr and Ta. [5][6][7] ZrO 2 is isomorphous to HfO 2 with a similar structure, 8 it is also the only thermodynamically stable solid form of zirconium with a simple fluorite structure. The tetragonal ZrO 2 and HfO 2 both have the highest dielectric constant (k∼40-50) whereas the monoclinic ZrO 2 has the lower dielectric constant (k∼20).…”

Atomic Layer Deposition of High k Dielectric and Metal Gate Stacks for MOS Devices

“…Wafer EOTs were calculated using Hauser's CVC model [12]. The co-injection ALD employed for HfSiOx ALD [7] was further extended to grow HfSiN films from TEMAHf/Si vapor mixture pulses and alternating pulses of NH 3 . For ALD TiN films, a volatile liquid inorganic precursor (TiCl 4 ) was used.…”

“…MOCVD of ZrSiO x was explored using liquid metal amide precursors [4,5], and HfSiOx deposition has also been reported using analogous precursors [6]. Recent advances in equipment design have provided the capability for ALD to deposit HfSiOx films of varying compositions from volatile metal-organic precursors in both single-wafer ALD [7] and multi-wafer batch ALD platforms [8]. This paper explores devices utilizing both HfO 2 and Hf x Si 1-x O gate dielectrics deposited by ALD from metal alkylamide precursors and ozone.…”

“…Both metal-organic and inorganic precursors, including TiCl 4 for TiN, TEMAHf for HfN, were reacted with NH 3 to grow ALD metal nitride films [10]. HfSiN films were deposited from TEMAHf/Si precursors using the precursor co-injection ALD technique [7] with alternating pulses of NH 3 . Work functions of these metal gates were extracted from measurements of MOSCAPs.…”