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Industrial Research And Consultancy Centre
Patent
Resonant Tunneling Magnetic Tunneling Junction Device
Abstract

This patent describes a system designed to enhance the switching characteristics of Magnetic Tunnel Junctions (MTJs). The system incorporates a free magnetic layer, a fixed magnetic layer, and a semiconductor quantum well, which is positioned between layers of metal oxide and connected to both the free and fixed magnetic layers. This configuration utilizes resonant tunneling to improve the spin transfer torque (STT) switching performance of MTJs. The resonant tunneling phenomenon significantly enhances tunnel magneto resistance (TMR) and allows for the engineering of various TMR regimes. The proof-of-concept suggests potential for developing more efficient STT switching devices.

Figure 1 (a) Illustrates a schematic of an existing tri-layer Magnetic Tunnel Junction (MTJ); (b) Illustrates an energy band diagram of the existing tri-layer MTJ; (c) Illustrates a schematic of a Resonant Tunneling Magnetic Tunnel Junction (RTMTJ), according to embodiments as disclosed in patent; (d) Illustrates an energy band diagram of the RTMTJ.

Problem Statement

The primary problem addressed by this invention is the optimization of switching characteristics in Magnetic Tunnel Junctions (MTJs). Traditional tri-layer MTJ structures exhibit issues such as high critical current densities required for switching and monotonic opacity to tunneling, which result in high power dissipation and potential tunnel barrier breakdown.

Uniqueness of the Solution
  • Enhanced TMR: The use of resonant tunneling significantly enhances tunnel magneto resistance. 
  • Lower Switching Voltage: The double barrier resonant tunneling structure can lower the switching voltage, reducing power dissipation and avoiding tunnel barrier breakdown. 
  • Increased Spin Torque: The specific heterostructures used in the quantum well facilitate a higher transverse spin torque, allowing for more efficient switching. 
  • Flexible Design: The ability to engineer various TMR regimes and adjust the barrier widths provides flexibility in design and application.
Prototype Details

The described system involves a prototype structure where a semiconductor quantum well (made of MgO-Ge or MgO-ZnO) is sandwiched between metal oxide layers and connected to CoFeB ferromagnet layers. The resonant tunneling effects and STT switching are optimized through careful engineering of the quantum well and barrier widths.

Current Status of Technology

The Resonant Tunneling Magnetic Tunnel Junction (RTMTJ) device is currently at the proofof-concept stage, with its switching characteristics extensively evaluated through advanced simulations based on the Non-equilibrium Green’s Function (NEGF) formalism and the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The device structure and performance have been theoretically modeled, demonstrating significant improvements in tunnel magnetoresistance (TMR) and reduced switching voltages compared to conventional tri-layer MTJs.

Technology readiness level

3

Societal Impact

Advanced Technology Development: The principles of resonant tunneling in MTJs can inspire further innovations in spintronics and quantum computing, potentially leading to breakthroughs in various high-tech fields.

Applications or Domain
  • Spintronic Devices: Enhancing the performance of spintronic devices which rely on MTJs. 
  • Magnetic Storage: Improving the efficiency and performance of magnetic storage devices, such as hard drives and MRAM (Magnetoresistive Random Access Memory). 
  • Sensors: Enhancing the sensitivity and efficiency of magnetic sensors. 
  • Quantum Computing: Potential applications in quantum computing, where precise control of spin states is critical.

Geography of IP

Type of IP

Application Number

3717/MUM/2014

Filing Date
Grant Number

438403

Grant Date
Assignee(s)
Indian Institute of Technology Bombay
**This IP is owned by IIT Bombay**