Ternary Content Addressable Memory Using Memory Diode
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Solution Overview
Problem
Current ternary content addressable memory (TCAM) designs face challenges in reducing chip dimension and power consumption, and are not fully compatible with standard CMOS processes, complicating manufacturing.
Innovation Solution
A ternary content addressable memory based on a memory diode with a structure comprising a bottom electrode, isolation layer, and memory layer stacked from germanium oxide, aluminum oxide, and hafnium oxide, using silicon oxide for isolation and titanium nitride/metallic nickel for the top electrode, allowing for reduced dimensions and power consumption, and compatibility with standard CMOS processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-volatile content memory units based on magnetic memory (MRAM) and phase change memory (PCM) are used, then data storage capability is improved, but structure complexity increases and manufacturing compatibility with standard CMOS process deteriorates
Solution Approach 1:
The patent extracts the core memory function from complex MRAM and PCM structures and implements it using a simple diode structure with selective oxidation. Only the essential elements (diode, oxidation layer, transistor) are retained while removing unnecessary complexity, achieving memory functionality compatible with standard CMOS processes.
Solution Approach 2:
The patent uses a disposable oxidation layer that can be selectively removed or modified to store data. This layer serves as a temporary but functional memory element that can be rewritten, providing non-volatile storage capability through a simple, CMOS-compatible material rather than complex magnetic or phase-change structures.
2Reliability
If non-volatile content memory units based on magnetic memory (MRAM) and phase change memory (PCM) are used, then data storage capability is improved, but manufacturing compatibility with standard CMOS process deteriorates
Solution Approach 1:
The patent creates a universal memory structure that can be manufactured using standard CMOS processes. The diode-based memory unit can perform multiple functions (storage, reading, writing) and is compatible with existing CMOS fabrication lines, making it universally manufacturable without requiring specialized MRAM or PCM production facilities.
Solution Approach 2:
The patent changes the physical state of the oxidation layer (present/absent, thick/thin) to encode data, rather than relying on magnetic properties or phase changes. This parameter-based approach uses standard CMOS-compatible materials and processes, enabling manufacturing with existing semiconductor fabrication technology.
3Reliability
If conventional TCAM structures are used, then data storage function is achieved, but chip dimension increases
Solution Approach 1:
The patent transitions from planar TCAM structures to a vertical stacking architecture where memory elements are arranged in multiple layers. By utilizing the vertical dimension, the chip can store more data in a smaller footprint, reducing overall chip area while maintaining full TCAM functionality through multi-layer diode-transistor stacks.
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 solution significantly reduces chip dimension and power consumption, simplifies the manufacturing process, and enhances compatibility with standard CMOS processes, making it suitable for advanced semiconductor integrated circuits.
Implementation Method 1
a memory layer, and a top electrode that are stacked from bottom to top. The memory layer is formed by stacking germanium oxide, aluminum oxide, and hafnium oxide from bottom to top
Implementation Method 2
the matching line is made of germanium, for generating a voltage signal after comparison of the search signal with the stored data
Data Source
AI summary
The present disclosure discloses a ternary content addressable memory based on a memory diode, which includes a plurality of kernel units having functions of storing data, erasing/writing data, and comparing data; the kernel units are arranged in an array, all kernel units in a unit of row are connected to a same matching line, and all kernel units in a unit of column are connected to a same pair of complementary search signal lines; the kernel unit includes two memory diodes; top electrodes of a first memory diode and a second memory diode are respectively connected to a pair of complementary search signal lines, and bottom electrodes of the first memory diode and the second memory diode are connected to a same matching line. The present disclosure can greatly reduce a chip dimension of the ternary content addressable memory and reduce power consumption; the ternary content addressable memory of the present disclosure has a simple structure, which effectively simplifies a manufacturing process and reduces a manufacturing cost; the present disclosure provides and achieves a memory diode that is compatible with a standard CMOS process, which is suitable for currently rapidly developing semiconductor integrated circuits.