# US 2021/0242831 A1 · Method for fabricating neuron oscillator including thermal insulating device

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- Number: US 2021/0242831 A1
- Document ID: US20210242831A1
- Status: Published application
- Kind: A1
- Application number: 17/059,244
- Filed: 2019-05-28
- Published: 2021-08-05
- Earliest claimed: 2018-05-28
- Assignees: Indian Institute of Technology Bombay
- Applicants: Indian Institute of Technology Bombay
- Inventors: Sandip Gangadharrao Lashkare; Vivek Saraswat; Pankaj Subhash Kumbhare; Udayan Ganguly
- Web page: https://patentgrep.com/patent/US20210242831A1

## CPC

- H03B 1/02: Structural details of power oscillators, e.g. for heating {(construction of transmitters H04B; features of generators for heating by electromagnetic fields H05B6/00)}
- G06N 3/04: Architecture, e.g. interconnection topology
- G06N 3/063: using electronic means
- G06N 3/065: Analogue means
- H03B 5/20: with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator
- H03B 28/00: Generation of oscillations by methods not covered by groups H03B5/00 - H03B27/00, including modification of the waveform to produce sinusoidal oscillations (analogue function generators for performing computing operations G06G7/26; use of transformers for conversion of waveform in AC-AC converters H02M5/18)
- H03B 29/00: Generation of noise currents and voltages {(gasfilled discharge tubes with solid cathode specially adapted as noise generators H01J17/005)}
- H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H)
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS

## Abstract

Accordingly the embodiments herein provide a method for fabricating a neuron oscillator (200a). The neuron oscillator (200a) includes a thermal insulating device connected with a resistor and a capacitor in series to produce self-sustained oscillations, where the resistor and the capacitor are arranged in parallel manner. The neuron oscillator (200a) eliminates a requirement of an additional compensation circuitry for a consistent performance over a time under heating issues. Additionally, an ON/OFF ratio of the neuron oscillator (200a) improves to a broader resistor range. Further, a presence of tunable synaptic memristor functionality of the neuron oscillator (200a) provides a reduced fabrication complexity to a large scale ONN. An input voltage required for the neuron oscillator (200a) is low (2-3 V) which makes it suitable to use with existing circuitries without using any additional converters. Additionally, an amplitude of the oscillations is a significant fraction of an applied bias which eliminates a need for an amplification.

## Claims

### Claim 1

A neuron oscillator, comprising
a thermal insulating device connected with a resistor and a capacitor in series to produce self-sustained oscillations, wherein the resistor and the capacitor are arranged in parallel manner

### Claim 2 (depends on 1)

The neuron oscillator of claim 1, wherein the thermal insulating device comprises:
a substrate, where the silicon substrate is thermally oxidized by a thermal oxidation process at a temperature to grow a silicon oxide;
a titanium and a platinum deposited on the silicon oxide by a sputtering process in an argon ambient;
a thermal insulating layer deposited by a radio frequency (RF) sputtering in an argon ambient at a room temperature; and
a tungsten placed on the thermal insulating layer by a photolithography and a lift-off process.

### Claim 3 (depends on 2)

The neuron oscillator of claim 2, wherein the temperature of the thermal oxidation process is 1000 degree Celsius.

### Claim 4 (depends on 2)

The neuron oscillator of claim 2, wherein the titanium and the platinum act as a bottom contact for the thermal insulating layer.

### Claim 5 (depends on 2)

The neuron oscillator of claim 2, wherein a stack of the silicon oxide, the titanium, the platinum, and the thermal insulating layer is annealed at 750 degree Celsius in a nitrogen ambient.

### Claim 6 (depends on 1)

The neuron oscillator of claim 1, wherein the thermal insulating layer generates a transient joule heating based hysteretic thermal runaway in its direct-current current-voltage (DCIV) characteristics.

### Claim 7 (depends on 1)

The neuron oscillator of claim 1, wherein the thermal insulating device comprises at least one of a praseodymium manganese oxide (PrMnO3) device, praseodymium calcium manganese oxide (PrCaMnO3) device, a calcium manganese oxide (CaMnO3) device, and a lanthanum strontium manganite oxide (LSMO).

### Claim 8 (depends on 6)

The neuron oscillator of claim 6, wherein the transient joule heating based hysteretic thermal runaway is caused due to minimal heat loss in the thermally insulating device.

### Claim 9 (depends on 1)

The neuron oscillator of claim 1, wherein a voltage across the capacitor determines the voltage across the thermal insulating device so as to generate a low resistance state and a high resistance state.

### Claim 10 (depends on 9)

The neuron oscillator of claim 9, wherein the low resistance state of the thermal insulating device generates charging and the high resistance state of the thermal insulating device generates discharging of the capacitor resulting in oscillations in the neuron oscillator.

### Claim 11 (depends on 1)

The neuron oscillator of claim 1, wherein the neuron oscillator is used in a coupled oscillatory neural network.

### Claim 12 (depends on 1)

The neuron oscillator of claim 1, wherein the neuron oscillator is used in a neuromorphic application.

### Claim 13

A method for fabricating a neuron oscillator, comprising
placing a resistor and a capacitor in parallel; and
connecting a thermal insulating device in series with the resistor and the capacitor to produce self-sustained oscillations.

### Claim 14 (depends on 13)

The method of claim 13, wherein the thermal insulating device is fabricated by:
placing a silicon substrate, where the substrate is thermally oxidized by a thermal oxidation process at a temperature to grow a silicon oxide;
depositing a titanium and a platinum on the silicon oxide by a sputtering process in an argon ambient;
depositing a thermal insulating layer by a radio frequency (RF) sputtering in the argon ambient at a room temperature; and
placing a tungsten on the thermal insulating layer by a photolithography and lift-off process.

### Claim 15 (depends on 14)

The method of claim 14, wherein the temperature of thermal oxidation is 1000 degree Celsius.

### Claim 16 (depends on 14)

The method of claim 14, wherein the titanium and the platinum act as a bottom contact for the thermal insulating layer.

### Claim 17 (depends on 14)

The method of claim 14, wherein a stack of the silicon oxide, the titanium, the platinum, and the thermal insulating layer is annealed at 750 degree Celsius in a nitrogen ambient.

### Claim 18 (depends on 14)

The method of claim 14, wherein the thermal insulating layer generates a transient joule heating based hysteretic thermal runaway in its direct-current current-voltage (DCIV) characteristics.

### Claim 19 (depends on 13)

The method of claim 13, wherein the thermal insulating device comprises at least one of a praseodymium manganese oxide (PMO) device, a praseodymium calcium manganese oxide (PrCaMnO3) device, a calcium manganese oxide (CaMnO3) device, and a lanthanum strontium manganite oxide (LSMO).

### Claim 20 (depends on 18)

The method of claim 18, wherein the transient joule heating based hysteretic thermal runaway is caused due to minimal heat loss in the thermally insulating device.

### Claim 21 (depends on 13)

The method of claim 13, wherein a voltage across the capacitor determines the voltage across the thermal insulating device so as to generate a low resistance state and a high resistance state.

### Claim 22 (depends on 21)

The method of claim 21, wherein the low resistance state of the thermal insulating device generates charging and the high resistance state of the thermal insulating device generates discharging of the capacitor resulting in oscillations in the neuron oscillator.

### Claim 23 (depends on 13)

The method of claim 13, wherein the neuron oscillator is used in a coupled oscillatory neural network.

### Claim 24 (depends on 13)

The method of claim 13, wherein the neuron oscillator is used in a neuromorphic application.