MTJ-Inductor Semiconductor Structure for On-Chip RF Integration
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Solution Overview
Problem
MRAM is not integrated with inductors, leading to increased costs and circuit board area requirements for RF applications, as inductors are typically assembled off-chip.
Innovation Solution
A semiconductor structure integrating a magnetic tunnel junction (MTJ) and an inductor, where the inductor is formed during the MRAM manufacturing process, utilizing vertical penetration through dielectric layers and a spiral coil structure to enhance magnetic energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inductors are assembled off-chip with MRAM, then RF application functionality is provided, but manufacturing cost increases and circuit board area increases
Solution Approach 1:
The patent merges the inductor and MRAM into a single integrated structure where the inductor is formed within the same semiconductor chip as the MRAM cell. The inductor utilizes the MTJ material layer and dielectric layers that are already present in the MRAM fabrication process, combining two separate components (inductor and MRAM) into one unified device that provides both RF functionality and memory storage without requiring separate assembly steps
Solution Approach 2:
The MTJ material layer serves dual purposes: it functions as the magnetic tunnel junction barrier layer for the MRAM cell and simultaneously serves as the conductive path for the inductor. The dielectric layers also serve multiple functions by providing both electrical isolation for the MRAM and the magnetic core structure for the inductor, thereby reducing the need for additional specialized layers and processes
2Adaptability or versatility
If inductors are assembled off-chip with MRAM, then RF application functionality is provided, but circuit board area increases
Solution Approach 1:
The inductor and MRAM are merged into a single integrated structure on the same semiconductor chip, eliminating the need for separate discrete inductor components on the circuit board. The inductor region is defined adjacent to the cell region on the same chip substrate, allowing both components to share the same physical space and reducing overall system footprint
Solution Approach 2:
The inductor is designed with a vertical three-dimensional structure that extends through multiple dielectric layers, utilizing the vertical dimension rather than only horizontal plane space. This vertical penetration allows the inductor to occupy space in the Z-direction, effectively reducing the horizontal footprint on the circuit board while maintaining sufficient inductance value
3Productivity
If inductor is formed during MRAM manufacturing process, then manufacturing steps are reduced, but inductor performance must be maintained
Solution Approach 1:
The inductor formation is merged with the MRAM manufacturing process by defining an inductor region adjacent to the cell region and forming the inductor structure using the same MTJ material layer and dielectric layers that are already being processed for the MRAM cell. This eliminates the need for separate inductor fabrication steps while maintaining component performance through optimized structural design
Solution Approach 2:
The inductor structure is designed with locally optimized features including a vertical penetration configuration through multiple dielectric layers, specific MTJ material layer thickness and composition, and a spiral coil structure with notches and conductive vias. These local structural qualities ensure that the inductor achieves the required performance characteristics (inductance, Q-factor, magnetic energy storage) while being fabricated using the same process steps as the MRAM
4Area of stationary object
If vertical penetration through dielectric layers is used, then space utilization is optimized, but manufacturing complexity increases
Solution Approach 1:
The inductor is designed to penetrate vertically through multiple dielectric layers (first, second, and third dielectric layers) rather than being confined to a single horizontal plane. This three-dimensional configuration utilizes the vertical Z-direction space within the semiconductor stack, effectively increasing the available space for inductor windings and improving space utilization without requiring additional horizontal chip area
Solution Approach 2:
The inductor structure is formed during the same manufacturing process steps that create the MRAM cell structure. The MTJ material layer and dielectric layers are prepared in advance as part of the MRAM fabrication sequence, and the inductor region is defined and formed using these pre-prepared layers, thereby avoiding the need for additional specialized processing steps despite the complex vertical geometry
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 integration reduces manufacturing steps, optimizes space utilization, and enhances magnetic energy storage capacity while simplifying the manufacturing process.
Implementation Method 1
magnetic tunnel junction (MTJ)
Implementation Method 2
when the coil structure is electrified, a larger electric field can be generated to improve the magnetic energy stored in the inductor
Data Source
AI summary
The invention provides a semiconductor structure with magnetic tunnel junction (MTJ) and inductor. The semiconductor structure comprising a substrate, a cell region and an inductor region defined on the substrate, a magnetic tunnel junction (MTJ) is located in the cell region, wherein the MTJ comprises a first MTJ material layer. And an inductor is located in the inductor region, wherein the inductor comprises a multi-layer structure, the multi-layer structure comprises at least one second MTJ material layer, wherein the material of the first MTJ material layer is the same as that of the second MTJ material layer, and viewed from a sectional view, the first MTJ material layer extends along a horizontal direction, and the second MTJ material layer comprises a horizontal part and two vertical parts, and the vertical part extends along a vertical direction.