Method for the Deposition of an Iron-Containing Film
Publication Date: 2010-Oct-25
The IP.com Prior Art Database
Disclosed herein are non-limiting embodiments of methods, apparatus, and compounds which may be used in the manufacture of semiconductor, photovoltaic, LCD-TFT, or flat panel type devices.
Iron (Fe), and its oxide phase, is a candidate for use in new types of memories, such as Magnetic Random Access Memory (MRAM) and Resistive Random Access Memory (ReRAM). In the case of MRAM, iron is used as an alloy with other metals, such as cobalt, whereas in ReRAM, the oxide phase is considered. Iron metal can also be considered for electrode purpose. For both applications, molecules (“precursors”) that enable Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) will be needed to solve the challenges created by the scaling of the electronic devices. The main requirements for CVD/ALD precursors include providing acceptable deposition temperature range, acceptable thin film growth rate, have sufficient thermal stability for being distributed in gas phase without decomposition, being liquid at room temperature, and being sufficiently volatile.
However, the deposition of iron and iron oxide is for the moment scarcely reported. Some iron amidinate molecules have been reported, but none of them are liquid, most of the molecules melt only above 100ºC (WO2004046417). Besides the thermogravimetry analyses (TGA) all exhibit non-desired patterns, such as multi-steps evaporation (Eur. J. Inorg. Chem., 2007, 1135-1142). Iron and iron oxide depositions are mentioned using Bis(N,N’-di-tert-butylacetamidinate) Iron but no data are provided about the experiments (WO204046417).
Iron oxide deposition in ALD mode is reported by using Fe(tmhd)3 and ozone (Lie et al., Thin Solid Films, 488, 2005, 74-81). However, Fe(tmhd)3 has a very high melting point (164ºC), and low vapor pressure which limit its usage in mass production.
Ferrocene-type precursors are also used for iron oxide deposition in ALD mode (Thin Solid Films, 517, 2009, 1874-1879). However the reported deposition temperatures are above 360ºC, which may be high for some applications.
Selective deposition on SiO2 vs tungsten is reported using Fe(CO)5 and H2 at 200-400ºC (Y.H. Low et al., Microelectronic Engineering, 83, 2006, 2229-2233). However, Fe(CO)5 is a hazardous material which implies transportation and handling issues.
Other carbonyl based iron molecules, such as Fe(CO)4L, and the associated deposition processes are reported (US5.372.849).
Heteroleptic iron molecule, such as FeCp(CO)2Me, and the corresponding CVD/ALD processes are reported (WO2009015271). However, the thermal characterization profiles of these molecules exhibit non-desired patterns, such as multi-steps evaporation.
Consequently there exists a need for suitable precursors for deposition in CVD and ALD mode to deposit iron containing thin films.
The present invention describes a method to form iron containing films...