# US 2021/0241831 A1 · Ternary content addressable memory based on memory diode

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- Number: US 2021/0241831 A1
- Document ID: US20210241831A1
- Status: Published application
- Kind: A1
- Application number: 17/049,585
- Filed: 2018-07-16
- Published: 2021-08-05
- Earliest claimed: 2018-05-14
- Assignees: Zhejiang University
- Applicants: Zhejiang University
- Inventors: Yi ZHAO; Bing CHEN
- Web page: https://patentgrep.com/patent/US20210241831A1

## CPC

- G11C 15/046: {using non-volatile storage elements}
- H10N 70/066: {by filling of openings, e.g. damascene method}
- H10N 70/20: Multistable switching devices, e.g. memristors
- H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices}
- H10N 70/8833: {Binary metal oxides, e.g. TaOx}
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

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.

## Claims

### Claim 1

A memory diode, comprising a bottom electrode, an isolation layer, a memory layer, and a top electrode that are stacked from bottom to top, wherein the memory layer is formed by stacking germanium oxide, aluminum oxide, and hafnium oxide from bottom to top, and the bottom electrode is made of germanium.

### Claim 2 (depends on 1)

The memory diode according to claim 1, wherein in an operation state of the memory diode, a bottom electrode of the memory diode is connected to ground, and a corresponding voltage is applied to a top electrode of the memory diode; so as to achieve transition between an off-state and an on-state of the memory diode.

### Claim 3 (depends on 2)

The memory diode according to claim 2, wherein resistance of the memory diode in the off-state suddenly decreases after being applied with a negative voltage, this process is referred to as SET, the memory diode changes from the off-state to the on-state and is regarded as a diode device; and the resistance of the memory diode in the on-state suddenly increases after being applied with a positive voltage, this process is referred to as RESET, the memory diode changes from the on-state to the off-state and is regarded as a resistor having high resistance.

### Claim 4

A ternary content addressable memory based on a memory diode, wherein the ternary content addressable memory comprises a number of kernel units having functions of data storing, data erasing/writing, and data comparing;
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;
each of the kernel units comprises a first memory diode and a second memory diode;
top electrodes of the first memory diode and the 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.

### Claim 5 (depends on 4)

The ternary content addressable memory based on the memory diode according to claim 4, wherein the matching line is made of germanium, and the pair of complementary search signal lines are metal lines connected to the top electrodes of the memory diodes.

### Claim 6 (depends on 4)

The ternary content addressable memory based on the memory diode according to claim 4, wherein the first memory diode and the second memory diode in the kernel unit cooperate with each other to store three logic states of [0], [1], and [don't care]: when the first memory diode is in an on-state and the second memory diode is in an off-state, the kernel unit stores a data bit [0]; when the first memory diode is in the off-state and the second memory diode is in the on-state, the kernel unit stores a data bit [1]; and when both the first memory diode and the second memory diode are in the off-state, the kernel unit is in a state of [don't care].

### Claim 7

The ternary content addressable memory based on the memory diode according to claim wherein when a data bit stored in the kernel unit is consistent with a search signal, it is in a match state (match), and when all kernel units on a same matching line are in the match state (match), the matching line outputs [0]; when a data bit stored in the kernel unit is inconsistent with the search signal, it is in a mismatch state (mismatch), and when one or more kernel units on a same matching line are in the mismatch state (mismatch), the matching line outputs [1].