Amorphous Blocking Layer for Magnetic Memory TMR Stability
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Solution Overview
Problem
Current magnetic memory devices face challenges in achieving high integration and low power consumption while maintaining reliable tunnel magnetic resistance (TMR) and exchange coupling characteristics, particularly due to the crystallization of blocking layers during thermal treatment, which affects the orientation and crystal structure of magnetic tunnel junctions.
Innovation Solution
Incorporating an amorphous metal compound blocking layer with a specific composition and thickness range, including ferromagnetic and non-metal elements, which remains in an amorphous state after thermal treatment, thereby preventing the transfer of crystal structures from electrodes to the seed layer and maintaining optimal TMR and exchange coupling characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking layer is thermally treated to improve device characteristics, then TMR and exchange coupling characteristics are improved, but the blocking layer crystallizes which degrades performance
Solution Approach 1:
The patent modifies the compositional parameters of the blocking layer by incorporating specific non-metal elements (boron, nitrogen) at controlled concentrations (15-50 wt%). This compositional change allows the blocking layer to maintain its amorphous state even after thermal treatment, resolving the contradiction between improving device characteristics through thermal treatment and maintaining the amorphous structure.
Solution Approach 2:
The patent creates a composite blocking layer material combining ferromagnetic metal elements (cobalt, iron, nickel) with non-metal elements (boron, nitrogen) and non-magnetic metal elements. This composite structure enables the blocking layer to simultaneously achieve good exchange coupling characteristics and maintain amorphous stability during thermal treatment, preventing crystallization while preserving functional performance.
2Productivity
If the blocking layer is made thinner to reduce device size, then integration density is improved, but TMR characteristics deteriorate
Solution Approach 1:
The patent optimizes the thickness parameter of the blocking layer within a specific range (0.1-20 Å) and combines it with compositional changes (adding non-metal elements). This dual parameter optimization allows the ultra-thin blocking layer to maintain sufficient TMR characteristics while enabling higher integration density, as the enhanced compositional stability compensates for the reduced thickness.
3Ease of manufacture
If conventional blocking layer materials are used, then manufacturing is simpler, but crystal structure transfer from electrode to seed layer occurs degrading performance
Solution Approach 1:
The patent introduces an amorphous blocking layer as an intermediary between the electrode and the seed layer. This amorphous structure acts as a buffer that prevents crystal structure transfer from the electrode to the seed layer during thermal treatment. The blocking layer absorbs the crystallization tendency, protecting the magnetic tunnel junction's exchange coupling characteristics while remaining compatible with conventional deposition processes.
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
This approach enhances the reliability and performance of magnetic memory devices by maintaining the amorphous state of the blocking layer, thereby improving TMR and exchange coupling characteristics, leading to more efficient and reliable magnetic memory devices.
Implementation Method 1
an amorphous state of the blocking layer is preferably maintained during and post thermal treatment
Implementation Method 2
the blocking layer is deposited, patterned and thermally treated
Implementation Method 3
A resistance value of the MTJ pattern may be changed depending on magnetization directions of the two magnetic layers
Implementation Method 4
The blocking layer may include ferromagnetic, non-metal and non-magnetic metal elements
Data Source
AI summary
Magnetic memory cells include a magnetic tunnel junction and a first electrode, which is electrically coupled to the magnetic tunnel junction by a first conductive structure. This conductive structure includes a blocking layer and a seed layer, which extends between the blocking layer and the magnetic tunnel junction. The blocking layer is formed as an amorphous metal compound. In some of the embodiments, the blocking layer is a thermally treated layer and an amorphous state of the blocking layer is maintained during and post thermal treatment.