YPtBi Sputtered Film Composition for High Spin Hall Angle
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Solution Overview
Problem
Existing SOT devices utilizing YPtBi materials face challenges due to the need for specific buffer layers and optimal processing conditions to achieve desired crystal orientation, which hinders their effectiveness in applications like MRAM devices and magnetic recording heads.
Innovation Solution
The formation of a YPtBi layer with a 1:1:1 stoichiometry using Kr, Ar, or Xe gas sputtering, combined with controlled power application to targets, achieves a high spin Hall angle and desired density between 9.7 g/cc to 11.2 g/cc, facilitating improved crystal orientation and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If YPtBi materials are used in SOT devices, then high spin Hall angle and electrical conductivity are achieved, but specific buffer layers and optimal processing conditions are required to achieve desired crystal orientation
Solution Approach 1:
The patent changes the processing parameters by using sputtering deposition with specific gas compositions (Kr, Ar, or Xe) and controlled power application to targets. This achieves the desired 1:1:1 stoichiometry and crystal orientation without requiring complex buffer layer structures, thus maintaining high spin Hall angle while reducing device complexity
Solution Approach 2:
The patent introduces a specific deposition environment using krypton, argon, or xenon gas as an intermediary medium during sputtering. This intermediary enables precise control over YPtBi film formation and crystal orientation, eliminating the need for multiple buffer layers while achieving reliable spin Hall effect performance
2Reliability
If YPtBi layer is formed with controlled stoichiometry and density, then high spin Hall angle is achieved, but trace amounts of Kr, Ar, or Xe gas must be managed in the layer
Solution Approach 1:
The patent converts the potential harmful effect of trapped Kr, Ar, or Xe gas atoms in the YPtBi layer into a beneficial process indicator. The presence of trace amounts (about 1% or less) of these gases is accepted and even used as a marker to verify that the sputtering process achieved the desired 1:1:1 stoichiometry and high density, thus ensuring high spin Hall angle without requiring absolute purity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a YPtBi layer with enhanced spin Hall angle, enabling effective operation in SOT devices such as MRAM and magnetic recording heads by ensuring optimal crystal orientation and electrical conductivity.
Implementation Method 1
Kr, Ar, or Xe gas is used to sputter the YPtBi to form the YPtBi layer or film
Data Source
AI summary
The present disclosure generally relates to topological semi-metal (TSM) based spin-orbit torque (SOT) devices, and methods of forming a TSM layer. The TSM layer of the SOT device comprises YPtBi having a 1:1:1 stoichiometry. The YPtBi has a density between about 9.7 g/cc to about 11.2 g/cc. Kr, Ar, or Xe gas is used to sputter the YPtBi to form the YPtBi layer or film. Trace amounts of Kr, Ar, or Xe are detectable in the YPtBi layer, where the YPtBi layer comprises about 1% of Kr, Ar, or Xe. One or more targets comprising YPtBi; YPt and Bi; PtBi and Y; Y, Pt, and Bi; or YBi and Pt can be used when forming the YPtBi layer. In embodiments where two targets are used to form the YPtBi layer, different amounts of power may be applied to each target.