Method for fabricating neuron oscillator including thermal insulating device

Patent metadata

Field	Value
Publication number	US-11323065-B2
Application number	US-201917059244-A
Country	US
Kind code	B2
Filing date	May 28, 2019
Priority date	May 28, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

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.

First claim

We 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, wherein a thermal insulating layer generates a transient joule heating based hysteretic thermal runaway in its direct-current current-voltage (DCIV) characteristics, wherein the transient joule heating based hysteretic thermal runaway is caused due to high thermal resistivity with respect to Silicon in the thermally insulating device, 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 layer;
a titanium layer and a platinum layer deposited on the silicon oxide layer 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 top-contact patterned layer placed on the thermal insulating layer by photolithography and lift-off process.

2. The neuron oscillator of claim 1 , wherein the temperature of the thermal oxidation process is 1000 degree Celsius.

3. The neuron oscillator of claim 1 , wherein the titanium layer and the platinum layer act as a bottom contact for the thermal insulating layer.

4. The neuron oscillator of claim 1 , wherein a stack of the silicon oxide layer, the titanium layer, the platinum layer, and the thermal insulating layer is annealed at 750 degree Celsius in a nitrogen ambient.

5. The neuron oscillator of claim 1 , wherein the thermal insulating device comprises at least one of a praseodymium manganese oxide (PrMnO 3 ) device, praseodymium calcium manganese oxide (PrCaMnO 3 ) device, a calcium manganese oxide (CaMnO 3 ) device, and a lanthanum strontium manganite oxide (LSMO).

6. 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.

7. The neuron oscillator of claim 6 , 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.

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

9. The neuron oscillator of claim 8 , wherein the neuron oscillator is used in a neuromorphic application.

10. 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,
wherein a thermal insulating layer generates a transient joule heating based hysteretic thermal runaway in its direct-current current voltage (DCIV) characteristics, and wherein the transient joule heating based hysteretic thermal runaway is caused due to high thermal resistivity with respect to Silicon in the thermally insulating device, 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 layer and a platinum layer 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 top-contact patterned layer on the thermal insulating layer by photolithography and lift-off process.

11. The method of claim 10 , wherein the temperature of thermal oxidation is 1000 degree Celsius.

12. The method of claim 10 , wherein the titanium layer and the platinum layer act as a bottom contact for the thermal insulating layer.

13. The method of claim 10 , wherein a stack of the silicon oxide layer, the titanium layer, the platinum layer, and the thermal insulating layer is annealed at 750 degree Celsius in a nitrogen ambient.

14. The method of claim 10 , 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).

15. The method of claim 10 , 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.

16. The method of claim 15 , 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.

17. The method of claim 10 , wherein the neuron oscillator is used in a coupled oscillatory neural network.

18. The method of claim 10 , wherein the neuron oscillator is used in a neuromorphic application.

Assignees

• Indian Inst Technology Bombay

Inventors

• Lashkare Sandip Gangadharrao
• Saraswat Vivek
• Kumbhare Pankaj Subhash
• Ganguly Udayan

Classifications

• G06N3/065

  Analogue means · CPC title

• G06N3/04

  Architecture, e.g. interconnection topology · CPC title

• H03B28/00

  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) · CPC title

• H03B1/02 Primary

  Structural details of power oscillators, e.g. for heating {(construction of transmitters H04B; features of generators for heating by electromagnetic fields H05B6/00)} · CPC title

• H03B5/20 Primary

  with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator · CPC title