Systems and methods for forming metal oxides using alcohols

Abstract

A method of forming (and an apparatus for forming) a metal oxide layer on a substrate, particularly a semiconductor substrate or substrate assembly, using a vapor deposition process, one or more alcohols, and one or more metal-containing precursor compounds.

Description

FIELD OF THE INVENTION [0001] This invention relates to methods of forming a metal oxide layer on a substrate using one or more alcohols and one or more metal-containing precursor compounds during a vapor deposition process. The precursor compounds and methods are particularly suitable for the formation of a metal oxide layers on semiconductor substrates or substrate assemblies. BACKGROUND OF THE INVENTION [0002] The continuous shrinkage of microelectronic devices such as capacitors and gates over the years has led to a situation where the materials traditionally used in integrated circuit technology are approaching their performance limits. Silicon (i.e., doped polysilicon) has generally been the substrate of choice, and silicon dioxide (SiO2) has frequently been used as the dielectric material with silicon to construct microelectronic devices. However, when the SiO2 layer is thinned to 1 nm (i.e., a thickness of only 4 or 5 molecules), as is desired in the newest micro devices, th...

AI Technical Summary

Benefits of technology

[0008] This invention provides methods of vapor depositing a metal oxide layer on a substrate. These vapor deposition methods involve forming the layer by combining one or more alcohols with one or more metal organo-amine precursor compounds (e.g., alkylamines or alkylimines-alkylamines) and / or metal alkyl precursor compounds. Significantly, the methods of the present invention do not require the use of water or a strong oxidizer, thus reducing (and typically avoiding) the problems of producing an undesirable interfacial oxide layer between the desired metal oxide layer and the substrate, and oxidizing other layers beneath the top layer. Typically and preferably, the layer is a dielectric layer.

[0019]“Atomic layer deposition” (ALD) as used herein refers to a vapor deposition process in which numerous consecutive deposition cycles are conducted in a deposition chamber. Typically, during each cycle the metal precursor is chemisorbed to the substrate surface; excess precursor is purged out; a subsequent precursor and / or reaction gas is introduced to react with the chemisorbed layer; and excess reaction gas (if used) and by-products are removed. As compared to the one cycle chemical vapor deposition (CVD) process, the longer duration multi-cycle ALD process allows for improved control of layer thickness by self-limiting layer growth and minimizing detrimental gas phase reactions by separation of the reaction components. The term “atomic layer deposition” as used herein is also meant to include the related terms “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE), gas source MBE, organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor compound(s), reaction gas(es), and purge (i.e., inert carrier) gas.

Problems solved by technology

The continuous shrinkage of microelectronic devices such as capacitors and gates over the years has led to a situation where the materials traditionally used in integrated circuit technology are approaching their performance limits.

However, when the SiO2 layer is thinned to 1 nm (i.e., a thickness of only 4 or 5 molecules), as is desired in the newest micro devices, the layer no longer effectively performs as an insulator due to the tunneling current running through it.

But vapor deposition processes typically involve the co-reaction of reactive metal precursor compounds with an oxygen source such as oxygen or water, either of which can cause formation of an undesirable SiO2 interfacial layer.

However, undesirable chlorine residues can also be formed.

Furthermore, zirconium and hafnium alkyls are generally unstable and not commercially available.

They would also likely leave carbon in the resultant films.

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