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 an electrode layer having a curved top surface on a top surface of a substrate;
- forming a stack of magnetic tunneling junction (MTJ) layers on the curved top surface of the electrode layer, wherein each layer in the stack of MTJ layers acquires a respective curved top surface from the forming of the stack of MTJ layers on the curved top surface of the electrode layer, and wherein defects associated with crystalline growth for each layer of the stack of MTJ layers migrate to outer portions of each layer during the forming of each layer of the stack of MTJ layers, wherein each respective curved top surface for each layer in the stack of MTJ layers spans a different distance over the substrate after the forming of the stack of MTJ layers on the curved top surface of the electrode layer, wherein the distance for each respective curved top surface is measured along a first direction that is substantially parallel to the top surface of the substrate;
- and
- removing the outer portions of each layer that contain defects associated with crystalline growth for each layer such that a remaining portion of each layer of the stack of MTJ layers is relatively free of defects associated with crystalline growth.
A method comprising:
- forming a conductive layer having an axially symmetric curved top surface on a top surface of a substrate;
- and
- forming a stack of magnetic tunneling junction (MTJ) layers on the curved top surface of the conductive layer, wherein the forming of the stack of the MTJ layers includes inducing strain in at least one layer of the stack of MTJ layers to cause defects in the at least one layer to migrate to an outer portion of the at least one layer, wherein the at least one layer includes a middle portion having a curved top surface and the outer portion has a flat top surface that is substantially parallel to the top surface of the substrate after the forming of the stack of the MTJ layers.
A method comprising:
- forming a stack of magnetic tunneling junction (MTJ) layers over a top surface of a substrate, wherein the forming of the stack of the MTJ layers includes inducing strain in at least one layer of the stack of MTJ layers to cause defects in the at least one layer to migrate to an outer portion of the at least one layer, wherein the at least one layer includes a middle portion having a curved top surface and the outer portion has a flat top surface that is substantially parallel to the top surface of the substrate after the forming of the stack of the MTJ layers;
- and
- removing the outer portion of the at least one layer after inducing strain in the at least one layer of the stack of MTJ layers.
Dependencies are inferred from the claim text.