# US 2006/0186496 A1 · System and method for processing a wafer including stop-on-alumina processing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2006/0186496 A1 - Document ID: US20060186496A1 - Status: Published application - Kind: A1 - Application number: 11/407,524 - Filed: 2006-04-20 - Published: 2006-08-24 - Earliest claimed: 2004-09-09 - Assignees: Tegal Corporation - Inventors: Robert Ditizio - Web page: https://patentgrep.com/patent/US20060186496A1 ## CPC - H10N 50/10: Magnetoresistive devices - H10N 50/01: Manufacture or treatment - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Magnetic tunnel junction (MTJ) devices can be fabricated by a stop-on-alumina process whereby the tunnel junction layer serves as the stop layer during plasma overetching of the upper magnetic layer. The resulting side walls of the MTJ device are non-vertical in the vicinity of the tunnel junction layer which serves to electrically isolate the upper magnetic layer from the lower magnetic layer. The gas employed during plasma overetching excludes halogen containing species which results in highly selective etching of the magnetic layer vis-à-vis the alumina tunnel barrier layer. The introduction of oxygen in the gas may enhance the reproducibility of the overetch process. Finally, plasma treatment with He and H2 followed by rinsing and baking subsequent to removal of the photoresist mask during the fabrication process enhances yield. ## Claims ### Claim 1 A magnetic tunnel junction device comprising: (a) a first or lower magnetic member; (b) a second or upper magnetic member; and (c) an insulating tunnel barrier layer that comprises a dielectric material located between the first magnetic member and the second magnetic member wherein at least one side portion of the second magnetic member and of the insulating tunnel barrier layer define a non-vertical profile which protrudes from the at least one side portion. ### Claim 2 (depends on 1) The magnetic tunnel junction device of claim 1 wherein the dielectric material comprises Al2O3. ### Claim 3 (depends on 1) The magnetic tunnel junction device of claim 1 wherein the first magnetic member is a fixed ferromagnetic layer having a magnetic moment that is fixed in a preferred direction in the presence of an applied magnetic field in a specified range and the second magnetic member is a free ferromagnetic layer whose magnetic moment is free to rotate in the presence of an applied magnetic field in the specified range ### Claim 4 (depends on 3) The magnetic tunnel junction device of claim 3 wherein the fixed and free ferromagnetic layers are formed from a material that is selected from the group consisting of NiFe, CoFe, CoFeB, NiFeCr, CoNiFe and mixtures thereof. ### Claim 5 (depends on 1) The magnetic tunnel junction device of claim 1 further comprising: (d) a support substrate; (e) a first conductive non-magnetic contact layer that is formed on the support substrate; and (f) a second conductive non-magnetic contact layer that is formed on an upper surface of the second magnetic member. ### Claim 6 (depends on 5) The magnetic tunnel junction device of claim 5 wherein the first and second conductive non-magnetic contact layers are formed from material that is selected from the group consisting of Ta, Ti and mixtures thereof. ### Claim 7 (depends on 1) The magnetic tunnel junction device of claim 1 wherein the insulating tunnel barrier layer defines a width that is greater than that of the second magnetic member. ### Claim 8 (depends on 1) The magnetic tunnel junction device of claim 1 wherein the second magnetic member has a width W2, the first magnetic member has a width W1, the insulating tunnel barrier layer which has a width W3, wherein W1≧W3>W2. ### Claim 9 (depends on 1) The magnetic tunnel junction device of claim 1 wherein an outer perimeter of the device includes at least part of the second magnetic member and of the insulating tunnel baffler layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer. ### Claim 10 (depends on 1) The magnetic tunnel junction device of claim 1 wherein an outer perimeter of the device includes at least part of the first magnetic member and of the insulating tunnel barrier layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer. ### Claim 11 A magnetic tunnel junction device comprising: (a) a first or lower magnetic member; (b) a second or upper magnetic member; and (c) an insulating tunnel barrier layer that comprises a dielectric material located between the first magnetic member and the second magnetic member wherein at least one side portion of the first magnetic member and of the insulating tunnel barrier layer define a non-vertical profile which protrudes from the at least one side portion. ### Claim 12 (depends on 11) The magnetic tunnel junction device of claim 11 wherein the insulating tunnel barrier layer defines a width that is greater than that of the second magnetic member. ### Claim 13 (depends on 11) The magnetic tunnel junction device of claim 11 wherein the second magnetic member has a width W2, the first magnetic member has a width W1, the insulating tunnel barrier layer which has a width W3, wherein W1≧W3>W2. ### Claim 14 (depends on 11) The magnetic tunnel junction device of claim 11 wherein an outer perimeter of the device includes at least part of the second magnetic member and of the insulating tunnel baffler layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer. ### Claim 15 (depends on 11) The magnetic tunnel junction device of claim 11 wherein an outer perimeter of the device includes at least part of the first magnetic member and of the insulating tunnel barrier layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer. ### Claim 16 A magnetic tunnel junction device comprising: (a) a first or lower magnetic member; (b) a second or upper magnetic member; and (c) an insulating tunnel barrier layer that comprises a dielectric material electrically separating the second magnetic member which has an outer perimeter positioned on an upper surface of the insulating tunnel barrier layer and the first magnetic member which is underneath the insulating tunnel barrier layer. ### Claim 17 (depends on 16) The magnetic tunnel junction device of claim 16 wherein the insulating tunnel barrier layer defines a width that is greater than that of the second magnetic member. ### Claim 18 (depends on 16) The magnetic tunnel junction device of claim 16 wherein the second magnetic member has a width W2, the first magnetic member has a width W1, the insulating tunnel barrier layer which has a width W3, wherein W1≧W3>W2. ### Claim 19 (depends on 16) The magnetic tunnel junction device of claim 16 wherein an outer perimeter of the device includes at least part of the second magnetic member and of the insulating tunnel baffler layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer. ### Claim 20 (depends on 16) The magnetic tunnel junction device of claim 16 wherein an outer perimeter of the device includes at least part of the first magnetic member and of the insulating tunnel barrier layer define a non-vertical profile, and the second magnetic member has a width that is less than that of the tunnel barrier layer.