Systems and methods for forming refractory metal oxide layers

Abstract

A method of forming (and apparatus for forming) refractory metal oxide layers, such as tantalum pentoxide layers, on substrates by using vapor deposition processes with refractory metal precursor compounds and ethers.

Description

FELD OF THE INVENTION [0001] This invention relates to method of forming a refractory metal (preferably, tantalum) oxide layer, and particularly to a method of forming a tantalum pentoxide layer, on a substrate using a reactive deposition process with a refractory metal precursor compound with an ether. BACKGROUND OF THE INVENTION [0002] In integrated circuit manufacturing, microelectronic devices such as capacitors are the basic energy storage devices in random access memory devices, such as dynamic random access memory (DRAM) devices, static random access memory (SRAM) devices, and ferroelectric memory (FERAM) devices. Capacitors typically consist of two conductors, such as parallel metal or polysilicon plates, which act as the electrodes (i.e., the storage node electrode and the cell plate capacitor electrode), insulated from each other by a layer of dielectric material. [0003] The continuous shrinkage of microelectronic devices over the years has led to a situation where the mat...

AI Technical Summary

Benefits of technology

[0022]“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) (see U.S. Pat. No. 5,256,244 (Ackerman)), molecular beam epitaxy (MBE), gas source MBE, organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor compound(s), reaction gas and purge (i.e., inert carrier) gas.

Problems solved by technology

The continuous shrinkage of microelectronic devices 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 about 10 Å (i.e., a thickness of only 4 or 5 molecules), as is desired in the newest micro devices, the dielectric layer no longer effectively performs effectively as an insulator due to the tunneling current running through it.

Unfortunately, this increase in dielectric constant of annealed crystalline Ta2O5 layers is counterbalanced by higher leakage currents through the crystal boundaries.

Metal nitride barrier layers are also likely to be oxidized by high temperature anneal processes.

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