Taiwan Semiconductor Manufacturing Comp. Ltd.

Headway Technologies, Incorporated

Applied Spintronics Technology, Inc.

Son Le

Guenole Jan

Luc Thomas

Santiago Serrano Guisan

Po-Kang Wang

Tai Min

Xizeng Shi

Santiago Serrano

A ferromagnetic resonance (FMR) measurement method is disclosed wherein a magnetic film or stack of layers is patterned into elongated structures having a length along a long axis. A magnetic field (H) is applied in two different orientations with respect to the long axis (in-plane parallel and perpendicular to the long axis) or one orientation may be perpendicular-to-plane. In another embodiment, H is applied parallel to a first set of elongated structures with a long axis in the x-axis direction, and perpendicular to a second set of elongated structures with a long axis in the y-axis direction. From the difference in measured resonance frequency (&#x394;fr) (for a fixed magnetic field and sweeping through a range of frequencies) or the difference in measured resonance field (&#x394;Hr) (for a fixed microwave frequency and sweeping through a range of magnetic field amplitudes), magnetic saturation Ms is determined using formulas of demagnetizing factors.

Method for measuring saturation magnetization of magnetic films and multilayer stacks

A scanning ferromagnetic resonance (FMR) measurement system is disclosed with a radio frequency (RF) probe and one or two magnetic poles mounted on a holder plate and enable a perpendicular-to-plane or in-plane magnetic field, respectively, at test locations. While the RF probe tip contacts a magnetic film on a whole wafer under test (WUT), a plurality of microwave frequencies (f) is sequentially transmitted through the probe tip. Simultaneously, a magnetic field (H) is applied to the contacted region thereby causing a FMR condition in the magnetic film for each pair of (H, f) values. RF output signals are transmitted through or reflected from the magnetic film to a RF diode and converted to voltage signals which a controller uses to determine effective anisotropy field, linewidth, damping coefficient, and/or inhomogeneous broadening for a sub-mm area. The WUT is moved to preprogrammed locations to enable multiple FMR measurements at each test location.

Ferromagnetic resonance (FMR) electrical testing apparatus for spintronic devices

A ferromagnetic resonance (FMR) measurement system is disclosed with a plurality of 'm' RF probes and one or more magnetic assemblies to enable a perpendicular-to-plane or in-plane magnetic field (H) to be applied simultaneously with a sequence of microwave frequencies (f) at a plurality of 'm' test locations on a magnetic film formed on a whole wafer under test (WUT). A FMR condition occurs in the magnetic film (stack of unpatterned layers or patterned structure) for each pair of (H, f) values. RF input signals are distributed to the RF probes using RF power distribution or routing devices. RF output signals are transmitted through or reflected from the magnetic film to a plurality of &#x201c;n&#x201d; RF diodes where 1&#x2264;n&#x2264;m, and converted to voltage signals which a controller uses to determine effective anisotropy field, linewidth, damping coefficient, and/or inhomogeneous broadening at the predetermined test locations.

Multi-probe ferromagnetic resonance (FMR) apparatus for wafer level characterization of magnetic films

A ferromagnetic resonance (FMR) measurement system is disclosed with a waveguide transmission line (WGTL) connected at both ends to a mounting plate having an opening through which the WGTL is suspended. While the WGTL bottom surface contacts a portion of magnetic film on a whole wafer, a plurality of microwave frequencies is sequentially transmitted through the WGTL. Simultaneously, a magnetic field is applied to the contacted region thereby causing a FMR condition in the magnetic film. After RF output is transmitted through or reflected from the WGTL to a RF detector and converted to a voltage signal, effective anisotropy field, linewidth, damping coefficient, and/or inhomogeneous broadening are determined based on magnetic field intensity, microwave frequency and voltage output. A plurality of measurements is performed by controllably moving the WGTL or wafer and repeating the simultaneous application of microwave frequencies and magnetic field at additional preprogrammed locations on the magnetic film.

Scanning ferromagnetic resonance (FMR) for wafer-level characterization of magnetic films and multilayers

A method and system for programming a magnetic memory is disclosed. The method and system further include turning on a word line current and turning on a bit line current. The word line current is for generating at least one hard axis field. The bit line current is for generating at least one easy axis field. In one aspect, the method and system further include turning off the word line current and the bit line current such that a state of the at least one magnetic memory cell is repeatably obtained. In another aspect, the word line current is turned off after the bit line current is turned off.

Growing community of inventors

Gilroy, CA, United States of America

Son Le