UV sensor with nonvolatile memory using oxide semiconductor films

Patent metadata

Field	Value
Publication number	US-9263124-B2
Application number	US-201314133389-A
Country	US
Kind code	B2
Filing date	Dec 18, 2013
Priority date	Dec 18, 2013
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

A ultra-violet sensor has a gate on a substrate, a dielectric formed over the gate and the substrate, an oxide semiconductor formed over the dielectric, and a source electrode and a drain electrode formed at the edges of the oxide semiconductor. A memory device has an array of ultra-violet sensors, each sensor having a gate on a substrate, a dielectric formed over the gate and the substrate, an oxide semiconductor formed over the dielectric, and a source electrode and a drain electrode formed at the edges of the oxide semiconductor, an array of ultra-violet light sources corresponding to the array of ultra-violet sensors, an array of detectors electrically coupled to the array of ultra-violet sensors, driving circuitry attached to the array of sensors and the ultra-violet light sources to allow addressing of the arrays, and a reset mechanism.

First claim

What is claimed is:

1. A ultra-violet sensor memory cell, comprising:
a gate on a substrate;
a dielectric formed over the gate and the substrate;
an oxide semiconductor formed over the dielectric, wherein the oxide semiconductor is comprised of a mixture of component materials, one of the component materials having a ratio of at least three to one to one of the other materials; the oxide semiconductor having a characteristic persistent photoconductivity that stores data;
a source electrode and a drain electrode formed at the edges of the oxide semiconductor; and
at least one detector electrically coupled to the ultra-violet sensor to read the data stored in the sensory memory cell.

2. The ultra-violet sensor of claim 1 , wherein the dielectric is selected from the group consisting of silicon dioxide, silicon dioxide and silicon nitride, aluminum oxide and tantalum oxide.

3. The ultra-violet sensor of claim 1 , wherein the oxide semiconductor is selected from the group consisting of indium gallium zinc oxide, indium zinc oxide, indium gallium tin oxide, indium gallium oxide.

4. The ultra-violet sensor of claim 1 , wherein the source and drain electrodes are one of the group consisting of molybdenum chromium, aluminum and indium tin oxide.

5. The ultra-violet sensor of claim 1 , further comprising an ultra-violet polymer over the oxide semiconductor.

6. The ultra-violet sensor of claim 5 , wherein the ultra-violet polymer is selected from one of the group consisting of PMMA, and an oxide heterostructure.

7. The ultra-violet sensor of claim 5 , wherein the ultra-violet polymer encapsulates the dielectric, the oxide semiconductor, the source and drain.

8. The ultra-violet sensor of claim 1 , further comprising a voltage source electrically connected to the gate.

9. The ultra-violet sensor of claim 1 , further comprising a heater thermally coupled to the substrate.

10. The ultra-violet sensor of claim 1 , wherein the mixture of materials comprises a mixture of 70%:15%:15% of indium gallium zinc oxide.

11. An ultra-violet sensor device, comprising:
an array of ultra-violet sensors, each sensor comprising:
a gate on a substrate;
a dielectric formed over the gate and the substrate;
an oxide semiconductor formed over the dielectric, the oxide semiconductor comprises of a mixture of materials in which one material has a ratio of at least three to one to one other material in the mixture; and
a source electrode and a drain electrode formed at the edges of the oxide semiconductor; and

an array of current sensors electrically coupled to the array of ultra-violet sensors; to detect which ones of the ultra-violet sensors are conducting current; and
a reset mechanism connected to the array of ultra-violate sensors capable of reducing current in the ultra-violet sensors to set them to zero.

12. The sensor device of claim 11 , wherein the reset mechanism comprises a heater thermally coupled to the substrate.

13. The sensor device of claim 11 , wherein the reset mechanism comprises a voltage supply electrically coupled to the gate.

14. A memory device, comprising:
an array of ultra-violet sensors, each sensor comprising:
a gate on a substrate;
a dielectric formed over the gate and the substrate;
an oxide semiconductor formed over the dielectric; and

a source electrode and a drain electrode formed at the edges of the oxide semiconductor;
an array of ultra-violet light sources corresponding to the array of ultra-violet sensors arranged to write data to the array of ultra-violet sensors;
an array of detectors electrically coupled to the array of ultra-violet sensors, the detectors to detect which sensors are conducting current;
driving circuitry attached to the array of sensors and the ultra-violet light sources to allow addressing of the arrays to read from and write to the array of ultra-violet sensors; and
a reset mechanism capable of reducing the current in the ultra-violet sensors to set the sensors to zero.

15. The memory device of claim 14 , wherein the array of ultra-violet light sources comprise of ultra-violet light emitting diodes.

16. The memory device of claim 14 , wherein the reset mechanism comprises a heater thermally coupled to the substrate.

17. The memory device of claim 14 , wherein the reset mechanism comprises a voltage supply electrically coupled to the gates of the array of ultra-violet sensors.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Lujan Rene A
• Ng Tse Nga
• Street Robert A

Classifications

• H10W90/00

  Package configurations · CPC title

• H10D30/6755

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H10F77/60

  Arrangements for cooling, heating, ventilating or compensating for temperature fluctuations · CPC title

• H10F55/25

  wherein the radiation-sensitive devices and the electric light source are all semiconductor devices · CPC title

• H10F39/107

  having multiple elements covered by H10F30/00 in a repetitive configuration, e.g. radiation detectors comprising photodiode arrays · CPC title