MTJ Device Performance by Controlling Device Shape
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJesmin Haq, Tom Zhong, Zhongjian Teng, Vinh Lam, Yi Yang
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Abstract
A layered thin film device, such as a MTJ (Magnetic Tunnel Junction) device can be customized in shape by sequentially forming its successive layers over a symmetrically curved electrode. By initially shaping the electrode to have a concave or convex surface, the sequentially formed layers conform to that shape and acquire it and are subject to stresses that cause various crystal defects to migrate away from the axis of symmetry, leaving the region immediately surrounding the axis of symmetry relatively defect free. The resulting stack can then be patterned to leave only the region that is relatively defect free.
Claims20
A method comprising:
- forming a stack of magnetic tunneling junction (MTJ) layers on a substrate, wherein the stack of MTJ layers includes a first layer and a second layer, wherein the first layer and the second layer in the stack of MTJ layers acquire a respective curved top surface from the forming of the stack of MTJ layers, wherein defects associated with forming the first layer and the second layer in the stack of MTJ layers migrate to outer portions of the first layer and the second layer during the forming of the stack of MTJ layers, wherein the curved top surface of the first layer in the stack of MTJ layers spans a first distance over the substrate and the curved top surface of the second layer in the stack of MTJ layers spans a second distance after the forming of the stack of MTJ layers, wherein the first and second distances are measured along a first direction that is substantially parallel to a top surface of the substrate;
- and
- removing the outer portions of the first and second layers that contain defects.
A method comprising:
- inducing strain in a first layer of a stack of magnetic tunneling junction (MTJ) layers disposed on a top surface of a substrate to cause defects in the first layer to migrate from a second portion of the first layer to a first portion of the first layer, wherein the first portion of the first layer has a first top surface that is substantially parallel to the top surface of the substrate;
- and
- removing the first portion of the first layer after the inducing of the strain in the first layer of the stack of MTJ layers.
A method comprising:
- forming a conductive layer on a top surface of a substrate;
- modifying the conductive layer to have a curved top surface;
- forming a stack of magnetic tunneling junction (MTJ) layers on the curved top surface of the conductive layer, wherein the stack of MTJ layers includes a first layer and a second layer disposed over the first layer, wherein the first layer and the second layer in the stack of MTJ layers have respective curved top surfaces, wherein defects associated with forming the first layer migrate to a first portion of the first layer during the forming of the stack of MTJ layers, wherein the curved top surface of the first layer in the stack of MTJ layers spans a first distance over the substrate and the curved top surface of the second layer in the stack of MTJ layers spans a second distance after the forming of the stack of MTJ layers, wherein the first and second distances are measured along a first direction that is substantially parallel to the top surface of the substrate;
- and
- removing the first portion of the first layer that contains defects.
Dependencies are inferred from the claim text.