A method for preparing magnetic tunnel junction arrays by ion beams of oxygen gas clusters

Abstract

The invention provides a method for preparing a magnetic tunnel junction array by an oxygen gas cluster ion beam, in which the magnetic tunnel junction is etched by irradiating the oxygen gas cluster ion beam in an atmosphere of carbonyl organic matter gas, during the process , has undergone a series of repeated cycle processes such as oxidation, adsorption, reaction, and desorption. Since the energy of a single oxygen atom / molecule is very low, it will not cause physical damage and redeposition. At the same time, due to the use of SiO 2 , SiON, SiN, SiC or SiCN, etc. as the hard mask for etching, the etching rate of the hard mask by the oxygen gas cluster ion beam in the atmosphere of carbonyl organic gas will be very low, so that the selective etched, protecting the top electrode.

Description

technical field [0001] The invention relates to a method for preparing a magnetic tunnel junction (MTJ, Magnetic Tunnel Junction) array, in particular to a method for preparing a magnetic tunnel junction array using an oxygen gas cluster ion beam (GCIB, Gas Cluster Ion Beam), which belongs to the magnetic random Memory (MRAM, Magnetic Radom Access Memory) manufacturing technology field. Background technique [0002] In recent years, MRAM using magnetic tunnel junction (MTJ) has been considered as the future solid-state non-volatile memory, which has the characteristics of high-speed reading and writing, large capacity and low energy consumption. Ferromagnetic MTJ is usually a sandwich structure, which has a magnetic memory layer, which can change the magnetization direction to record different data; an insulating tunnel barrier layer in the middle; a magnetic reference layer, located on the other side of the tunnel barrier layer, which The direction of magnetization remains...

AI Technical Summary

Problems solved by technology

The two etching techniques have their own advantages and disadvantages. In order to obtain a higher etching rate, single ions are usually accelerated to a very high energy range. The accelerated high-energy ions usually destroy the crystal structure. At the same time, because of physical sputtering Or the re-deposition of chemical etching by-products will also increase. Usually, after the magnetic tunnel junction is etched, a layer of damaged layer / deposition layer will be formed on the side wall, which will affect the magnetic and electrical properties of the magnetic tunnel junction. If there is a winner, it will directly lead to a short circuit from the reference layer to the memory layer, which is not conducive to the improvement of the yield of magnetic memory

[0006] In addition, in the current manufacturing process, metal tantalum, titanium, tungsten or its nitrides are used as the hard mask for etching MTJ, and whether the RIE or IBE process is used, the hard mask is greatly consumed , thus forming an elliptical mold cap, which will be very detrimental to the connection between the MTJ and the CMOS bit line

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